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View Full Version : Front Spring Issues, Death Wobble FJ60


rover67
09-12-2011, 08:09 PM
Howdy Folks.

So I ran OME Heavies for about 3 years until I broke two rear springs. Long Shackles and some 4 degree caster spacers to make it track OK.

Last year I got some Alcans. they were 4" lift springs and although they claimed that the springs were custom, they quickly squashed my requests for specific things (like spring length, shackle length, and caster correction) and told me they had a set of numbers to build FJ60 springs from, so with maybe some of my weights I would be ready to go. I figured they knew better so off I went.

I got them and installed them. They took shims in the back to get the pinion angle right, and they took monster shims in the front (8 degrees) to get me even close to right. I was a littel dissapointed but I figured it was done so I ran it.

Well, one trip to spring creek and some aggressive driving and the front left spring flattened. I called them up and they wouldn't replace the spring, just gave me a deal to the tune of $200 for the one spring.

So.... now I have this ridiculous death wobble at like 40mph. So I started looking at stuff. The tie rod ends seemed kinda worn, so I replaced them. The wheel bearings were kinda loose so I tightened them. Got the tires rebalanced, rotated them... Still no changes.

I also notice the rig is leaning a lot where it used to be level. The front left (the spring that I replaced once) is much flatter than the front right. I also keep looking at those ridiculous shims. So... a few things are in my mind. should I call alcan and try and get a set of front springs that don't use the shims? is that even possible? I am going to get the alignment checked to see where the caster is at, but first I want to rebuild the knuckles... I think maybe the trunion bearings are getting worn since the last time I did them was 70k miles ago.

Also my shackles are angled out at the part that hits the springs, like 5 or 10 degrees. They basically started out like that when I did the springs... seemed like the springs were twisted or something.

I know I am talking about two issues here, but I kinda think that I might be needing to address it all at once.

Any thoughts? input?

I am also tempted to get rid of the long shackles and cut the fenders instead... I have to think those are contributing to my issues.

TIMZTOY
09-12-2011, 09:02 PM
davez off road (http://www.davezoffroadperformance.com/store/no-death-wobble-shackles.html) no death wobble shackles.. i know there for the pickups. but i dont see why it wouldnt work ass long as they fit. otherwize replace the leaf spring bushings. also tighten the trunion bearing bolts

Jacket
09-12-2011, 09:19 PM
Tighten your panhard rod. Just kidding.....

So if the original springs were "custom", then how do you know they sent you an exact matching replacement for the front spring you broke?

And with your shims, what degree are they? With 4" springs plus oversized shackles and 35" tires, maybe the shims aren't right and your pinion angle is off?

rover67
09-12-2011, 09:38 PM
I have some shorter shackles and new bushings on order from Kurt, I actually forgot to mention that...

Shims are 8 degrees, they gave me just over a degree of caster. I have run around 1 degree with the 35's and the OME's and it did OK. I know I need more though, that's why I am tempted to throw shorter shackles on there.

Tim, in these axles the trunion bearing preload is adjusted by shims. I have new trunion bearings on the way, I am just going to replace them when they get here. Maybe i'll find a mess in there when I open it up.. I kinda hope I will...

Oh, and the original springs weren't really custom I don't think... I think they were alcan's out of the box 4" springs for 60's.

treerootCO
09-13-2011, 09:06 AM
Just a thought, no evidence to support my theories but I am willing to wager that springs aren't made like they used to be. A stock set of mitsu springs lasted 52 years with a little sagging. So far, I have blown through five sets of springs on my 40, and a combination of the 5 sets, in just a few years. Each time, the spring just gives up. The longest lasting set was a Northern Spring and the set that lasted one trip to Buena Vista was a set of Pinnacles. Perhaps it is the metal they are sourcing these days. Remember the 1973 sheet metal they used in 40s that cracked instead of flexing? Who knows but what can Alcan do if their metal is low grade. Not much of a choice if the supply has been tainted.

TIMZTOY
09-13-2011, 11:51 AM
Tim, in these axles the trunion bearing preload is adjusted by shims. I have new trunion bearings on the way, I am just going to replace them when they get here. Maybe i'll find a mess in there when I open it up.. I kinda hope I will....

i ment the bolts/nuts.. i found mine to be really loose to the point they almost fell off and snaped all the bolts. :eek: . just somthing to check with a tool real quick

rover67
09-13-2011, 11:55 AM
cool i'll double check them. I usually check the nuts before every trip wheeling.

Yeah Mike, I bet the metal the springs are made out of sucks now. Not real sure how to address that other than to not use them so much.

wesintl
09-13-2011, 12:03 PM
sell it and buy a 100. a 140 is a good combo

60wag
09-13-2011, 12:16 PM
Are there any options that have more leaves in the pack? Not to make a stiffer spring, but to reduce the bending strain on each individual leaf. The old school OME's had more thinner leaves that the stock arrangement. I thought that is what enabled them to have more deflection without permanently deforming the spring. It's probably more expensive to make more leaves so the lower cost options migrate toward fewer pieces of thicker material.

How about cutting out the leaf spring junk and welding in a set of 80 axles with coils?

nuclearlemon
09-13-2011, 05:39 PM
that's sad to hear, since i had 4" alcans on my 60 and loved them (after my suckass pinnacles...your alcan story sounds like my pinnacle story). :(

rover67
09-13-2011, 05:59 PM
that's sad to hear, since i had 4" alcans on my 60 and loved them (after my suckass pinnacles...your alcan story sounds like my pinnacle story). :(

what'd you do for shackles and shims?

Uncle Ben
09-13-2011, 06:32 PM
what'd you do for shackles and shims?

I had 4 " Alcans on the front of my 62 also and loved them! I ran homemade 4" beefy shackles and I repearched my front axle. No problems! If I would have kept it or if I build another one I would have done a shackle reverse. I dislike spring overs especially on wagons as they get too "tippy" for my liking plus the axle wrap front and rear is nasty. I will add that I had horrible luck with OME shackles deforming....total crap shackles in my nsho!

J Kimmel
09-13-2011, 08:24 PM
FWIW on my old 4Runner it was the longer shackles that caused my death wobble. I had Alcans all the way around and they were great. Yes they would lean based on the last direction you turned, but thats a soft spring, a compromise. I ran stock shackles forever, and they were great. As soon as I installed a small lift shackle it hit me every time about 25 mph, and magically went away when I went back to stock...

can't believe your shims have lasted this long? The whole reason I did links in the front of my current incarnation was the fact that I couldn't make them last more than a trip or two :)

nuclearlemon
09-13-2011, 09:02 PM
4 or 4 1/2 inch springs, 1 inch over shackles and iirc 4degree shims

BreckBJ44
09-13-2011, 10:09 PM
I have Alcans on my 44 and love them They are stiff as **** but I asked for them that way. I have long shackles (look about the same as yours) and don't have any wobbling. I only run a 2.5 degree shim in the front and while it doesn't steer well, I don't wobble... Could it be from too much caster correction?

K

rover67
09-13-2011, 11:21 PM
OK, So it sounds like maybe the ridiculously long shackles are not so good. Kraig, maybe your stiff springs work with longer shackles because it's all stiffer overall. Ige, thanks for the info, looks like shorter shackles again and the 4 degree shims is what I ran back with the shorter shackles as well.

So anyways, I got some stockish height ones today in the mail and will be putting them on soon. That'll make the caster correction less and I'll benefit from the shorter ones not moving so much maybe. Also got new bushings.

Jeremy, The 8 degree shims have lasted a while... but they look scary when i look at them every time...I stay on top of making sure the u bolts are tight because they worry me. Maybe a cut and turn is in order along with shorter shackles... then trim the body to work. I already clearanced the **** out of the oil pan a few months ago.

Debating now whether or not to call alcan and see if they say anything about the saggy front left spring.

And yes Wes, I have actually been thinking about a new rig... I want to make sure this one is solid before thinking about selling it though.

Thanks for the brainstorming and input folks I appreciate it

Caribou Sandstorm
09-14-2011, 10:59 AM
What about running a 255 or 285 tire for the Maze? Would that help in your prep for a stable platform and to be able to sell the 60 down the road?

No body work would be needed, right?

Plus you will save a bundle on gas..

Just a thought.

Uncle Ben
09-14-2011, 11:11 AM
And yes Wes, I have actually been thinking about a new rig... I want to make sure this one is solid before thinking about selling it though.

Thanks for the brainstorming and input folks I appreciate it

Are you sure you want to sell the 60? I miss mine very much as you know. Please don't tell me your giving up technical wheeling and following the geriatric trend of getting a boulevard Cruiser!

nakman
09-14-2011, 11:37 AM
I'll echo the idea that your springs sagged now your caster is different. Could you tack the shims to the u-bolt plates? I know it would be more grinding later, but it would erase a variable.. let me know if I can help with more silly ideas...


What about running a 255 or 285 tire for the Maze? .

there's a thought.. or we could take a 40? or an 80, or a 100.. or just ride with Davis. :drink: :lmao:

Jacket
09-14-2011, 01:36 PM
I'm in the "shorter shackles", "new bushings" and "less shimming" camp.

rover67
09-14-2011, 02:53 PM
I am gonna keep the 35's on there, still want to make that formula work plus anything smaller than 35's would suck with the 4.88's.. I like to drive 75+.

I called Alcan and explained the sagging spring to them, they are gonna call me back. we'll see what they come up with. Hopefully they are willing to help me out since the first time they made me pay for my replacement spring.

Not worried about getting anything ready for the maze really, it should be fine.

And I like my 60, that's why I'm just thinking now. not sure what if anything i'd want to replace it with.

wesintl
09-14-2011, 03:02 PM
replace the shim with a cut and turn axle.

60wag
09-14-2011, 03:49 PM
It would be interesting to measure the setup as is to see what the caster is - maybe after the new trunion bearings. The shackles are a bit long but not crazy long, def' not long enough to make for those jumbo shims. Even if you put stock length shackles on there, the shims will only come down by 2-3 degs. I think the springs are the problem.

If the caster is significantly different than it used to be, the springs must have changed. Now if the truck hadn't left pavement and was powered by a 2F, I'd say those are lame springs. But having witnessed some spirited excursions into the dirt and rocks with that truck, is it possible that the engine torque and severe conditions have bent the springs? Maybe axle wrap caused a permanent reduction in caster? - although it seems like it'd wrap the axle in the wrong direction to reduce caster.

Uncle Ben
09-14-2011, 03:58 PM
Marco, I have a caster camber level you are welcome to use. I need to head to Boulder so I'll drop it off at your house.

rover67
09-14-2011, 05:55 PM
alriight, im going to get a baseline on the alighnment and do the trunion bearings then check it again. i talked to alcan and they said take the springs off andmeasure their free height, ill do that after. gotta wait till next week as i wont be back till then. kevin, thatd be sweet to be abble to borrow your setup. al's at home and can grab it.

Caribou Sandstorm
09-14-2011, 06:16 PM
I am gonna keep the 35's on there, still want to make that formula work plus anything smaller than 35's would suck with the 4.88's.. I like to drive 75+.

I called Alcan and explained the sagging spring to them, they are gonna call me back. we'll see what they come up with. Hopefully they are willing to help me out since the first time they made me pay for my replacement spring.

Not worried about getting anything ready for the maze really, it should be fine.

And I like my 60, that's why I'm just thinking now. not sure what if anything i'd want to replace it with.

Yep I forgot about the 4.88s...60s are at the top of my list as well. I have been tinkering with what if I ever get a job where I have to have a company car and would I sell the runner and get a wagon...

FJBRADY
09-14-2011, 06:25 PM
I have been tinkering with what if I ever get a job where I have to have a company car and would I sell the runner and get a wagon...

A wagon like this?

Uncle Ben
09-14-2011, 07:02 PM
alriight, im going to get a baseline on the alighnment and do the trunion bearings then check it again. i talked to alcan and they said take the springs off andmeasure their free height, ill do that after. gotta wait till next week as i wont be back till then. kevin, thatd be sweet to be abble to borrow your setup. al's at home and can grab it.

I did drop it by....it's on the bench outside the back Mead portal! :lmao:

rover67
09-14-2011, 09:46 PM
Sweet, thanks Kevin, I owe ya one!

Steve, that's actually kind of a sweet looking wagon :D

Caribou Sandstorm
09-14-2011, 11:23 PM
A wagon like this?

That is some mega departure angle though..

Rezarf
09-15-2011, 09:05 AM
Getting rid of my Thornbirds got rid of my death wobble ;)

Sorry for your troubles Marco, I am interested to see what cures it. I have nothing to offer over whats been said, but it sounds like you have some good folks following this one. :risingsun:

rover67
09-25-2011, 02:57 PM
Alright, Thanks to Kevin's generosity I was able to mesure camber and caster in-house. Super sweet...

Front left has 2.25* + Caster and 1.125* + Camber
Front Right has 1.75* + Caster and 1.5* + Camber

This is with the front axle weighted.

I am going to start taking apart the axle to check trunion bearings and will be removing the springs to check free height and to swap the shackles with shorter one.

rover67
09-25-2011, 05:24 PM
took off the 5.5" shackles and threw on the shorter 3.25" ones. The caster went to around 4.5 degrees for both sides. Gonna take it for a test drive.

rover67
09-25-2011, 06:19 PM
OK, the Death Wobble is still there. Now it is at a solid 45mph, and kinda hangs in there until you pass like 60mph. Enough to shake the front end of the truck apart it seems.

Time to dig into the knuckles.

rover67
09-25-2011, 08:45 PM
well, the knuckles actually looked great. the trunion bearings were slightly worn so I went ahead and replaced them. We'll see how it does tomorrow.

Any suggestions on how much toe to run?

nakman
09-25-2011, 09:06 PM
Those old bearings look kind of worn to me.. the one on the right has about 1mm of shiny spot on it, like it was only using the top part of the bearing, not the whole bearing? Which suggests maybe too many shims, and they weren't pushed down tight enough.. guessing there. :confused:

Rezarf
09-25-2011, 09:14 PM
Marco, have you checked your tires? Seriously, all my issues vanished when I got my tires running true.

rover67
09-25-2011, 10:14 PM
yeah, I kinda agree.. they actually look worse now that I look at them again...

I kinda don't think they were really the issue though, but it was time to service them for sure. They must have something like 80k miles on them with lots of wheelin'

Yeah, Drew, I also agree with you, It might be the tires. That's a pretty expensive one to address, but it may be the only way. They sure seem like they have worn nice though, and rotating them didn't change anything at all.. I wouldn't be too happy honestly if it were the tires. these only have like 20k on them, maybe less.

We'll see. Tomorrow I gotta get some grease. O'Riely was the only place open near me and they only had some crap stuff I'm not sticking in there for the next 80k. I got the knuckles back on, but don't have enough grease to do the rest of it all.

Uncle Ben
09-25-2011, 10:35 PM
well, the knuckles actually looked great. the trunion bearings were slightly worn so I went ahead and replaced them. We'll see how it does tomorrow.

Any suggestions on how much toe to run?

1/8-3/16" toe in I would lean toward the 1/8"


Are you sure your steering box is tight and your stabilizer isn't cavitated (shot).

nakman
09-25-2011, 10:40 PM
those races look a little jacked too.. not sure if it's the root cause here, but things will be happier with new trunion bearings.


Want to steal the tires/rims off the 80? You're welcome to them.. not sure if the BS is the exact same but heck it's 16" so shouldn't be clearance issues.. but you're welcome to borrow a very true running set of 35's for diagnostic reasons. lemme know!

rover67
09-25-2011, 10:54 PM
Just read this in another forum:

There are two schools when it comes to alignment. Too much caster and too much toe-in can induce death wobble. Too little caster and too much toe-out can cause wandering. Identify your symptom. If the tires start oscillating and hopping violently, you've got death wobble. Increasing the toe setting to as much as 3/8-inch toe-out (yes, readers toe-out; no misprint) has been known to help, or if possible, dialing the caster back to 3-4 degrees positive (bottom ball joint in front of top). The larger your tires, the less caster you should need.

I know I have a ton of toe....

Uncle Ben
09-25-2011, 10:56 PM
Just read this in another forum:

There are two schools when it comes to alignment. Too much caster and too much toe-in can induce death wobble. Too little caster and too much toe-out can cause wandering. Identify your symptom. If the tires start oscillating and hopping violently, you've got death wobble. Increasing the toe setting to as much as 3/8-inch toe-out (yes, readers toe-out; no misprint) has been known to help, or if possible, dialing the caster back to 3-4 degrees positive (bottom ball joint in front of top). The larger your tires, the less caster you should need.

I know I have a ton of toe....

toe out will make tires disappear!

rover67
09-26-2011, 09:31 PM
OK, entire front axle rebuilt. Everything is repacked, new bearings everywhere and all new seals.

I measured the toe......


wait for it....

I have almost an inch of toe in. I am guessing that's the issue. I am going to drive it without changing anything just to see what the axle rebuild did, then pull it into the garage to adjust the toe.

Gotta take mamasita to dinner though, so it looks like a test drive is all we'll get tonight. we'll leave the toe adjustment for tomorrow.

TIMZTOY
09-26-2011, 09:33 PM
1/8" - 1/4" toe in is normal

Caribou Sandstorm
09-26-2011, 10:36 PM
Marco are you off this week or doing this after work?

rover67
09-26-2011, 10:48 PM
Just after work. How come?

Well, The good news is the Mondongo Burrito at Efrains' was Delicious...

The bad news is the death wobble is still there. Time to adjust the toe and take it for another test drive.

Caribou Sandstorm
09-26-2011, 11:29 PM
Just after work. How come?

Well, The good news is the Mondongo Burrito at Efrains' was Delicious...

The bad news is the death wobble is still there. Time to adjust the toe and take it for another test drive.

If you were off, I was going to stop by. Working light Wed-Fri.

rover67
09-26-2011, 11:50 PM
ahh yes, bummer. Nope, gotta work man. Actually ridiculously busy lately with the day job. Stop by anyways one night just give me a buzz.



Soo....... I set it up with as close to 1/8" toe in as I could and took it for a drive. So far so good, no death wobble at all!!! It tracks a lot nicer too.

I am now wondering if I should leave the shorter shackles on it or throw the long ones back on... The shorter ones will just mean I have to cut a lot more out of the front fenders.

nakman
09-27-2011, 04:05 PM
nice work! i would put the long shackles back on... but how did your toe get to be so much, did you bend a tie rod?

60wag
09-27-2011, 06:16 PM
Do you still have the mega shims in there?

rover67
09-27-2011, 06:28 PM
Do you still have the mega shims in there?

Yep. I have a little more than 4* of caster with them in there.

I was going to weld them to the perches if I kept them..

Jacket
09-27-2011, 08:28 PM
Seems like it would be worth swapping the shackles back just to see.

Rezarf
09-27-2011, 10:21 PM
Out of curiosity, what do you reference to measure the toe in? The brake rotor front and rear, or the tire? Don't know that I ever thought about it before. Thanks

Air Randy
09-28-2011, 10:35 AM
Since I have disks in the front I pull the wheels off. I have 2 pieces of angle iron that are straight and the same size. I C clamp them to each rotor using a level and ensuring each piece is centered with the hub the same on both sides. Then you just take the front vs rear measurements.

On my 40, after we converted it from a 40 axle to a 60 axle, ****** (name deleted to spare the guilty) forgot to adjust the toe-in. Since the 60 axle is several inches wider than the 40 axle, I had like 1.5" of toe-in. I also had occassional death wobble (which was a first for this rig). Needless to say there was excessive tire wear too. Once I reset the toe to 1/4" the wobble never returned and the vehicle is super stable at highway speeds, no wandering, etc. I'm beeting your toe in issue was the root of your problem, but as others have asked, how did it get so far out of whack?

rover67
09-28-2011, 11:37 AM
You know I'm not sure how the toe changed so much.. I did change the tie rod ends recently but I set it back to where it was by measuring tie rod end length. Maybe I missed something due to a dumb error on my part (mixed up numbers), but I don't think so since it had the wobble before I changed the tie rod ends.

The tie rod is not bent either.

Only thing I can guess is that the toe has been like this for a LONG time and it only recently became a problem due to the tires getting a bit older? I got it "professionally" aligned a while back and maybe they messed it up? I need to look for their sheet.

rover67
10-17-2011, 10:24 AM
Well, After a nice wheeling trip this weekend I have determined that the Death Wobble is still there. The weird thing was that it was driving fine around boulder for a few days, and it drove fine down 93 to Golden.. But when we got on 6 to head to Idaho Springs it came back just like it was before and persisted throughout the day.

I am pretty convinced that everything in the front end is perfect, so I am now thinking tires and wheels.

I am going to throw the 40's tires and wheels on there first to see if that fixes it, then look at maybe checking to see how bent all the wheels are.

Jacket
10-17-2011, 05:48 PM
Bummer. I've got a spare set of stock 80 tires on 80 rims if don't want to mess with your 40.

Uncle Ben
10-17-2011, 05:51 PM
Bummer. I've got a spare set of stock 80 tires on 80 rims if don't want to mess with your 40.

Ditto....have the 80 e-test wheels and tires stacked besides the garage just waiting for the next use.

rover67
10-17-2011, 05:57 PM
Alright cool, I'll probably just throw the 40 on jack stands in the mean time, but I may call one of you guys.

rover67
10-17-2011, 11:06 PM
Well, earlier tonight I put the rig up on jackstands and ran it in 4wd at speed where i could look at all the wheels. I have 3 pretty bent ones one being out by about 1/2", and the next worse one being around 1/4" out.

Anyways, I threw on the 40's wheels on the front only and drove it about 60 miles. It ran great until I took the last turn off of 36 onto baseline to head home when the wobble Juuuuuust slightly tried to come back.

I am going to drive it more tomorrow, but am tempted to get a new set of wheels. They are only like 225 for a set of 5 from summit. I think I got the 1500lb rated ones last time without knowing any better, this time I was looking at the 2100lb ones.

rover67
10-17-2011, 11:09 PM
Also, I read somewhere that too much caster might actually hurt, so i am tempted to go back to 2 degrees or so instead of the 4-5 I'm at now.

TIMZTOY
10-18-2011, 12:06 AM
Out of curiosity, what do you reference to measure the toe in? The brake rotor front and rear, or the tire? Don't know that I ever thought about it before. Thanks

measure off the rim's lip. make a mark with either some tape or marker so that your measuring the same spot. you could also do randy's thing. jack up the front, let sit in 2 jack stands remove both rims and atach a stright edge as close to the hub as possible. to get the most accurate reading.. but as long as you measure the same spot from driver and pashenger then it really dosent matter.

Also, I read somewhere that too much caster might actually hurt, so i am tempted to go back to 2 degrees or so instead of the 4-5 I'm at now.

yes to much caster can hurt. expectually when its damn near 0 then the tire will just do what ever it wants. in stead of staying on track and stright if you dont have enough caster it will wonder or (wobble in some cases). to much camber (but equale cross camber) will ware tires out. proper camber will return tires to stright after turning. unequale cross camber will cause a pull or dirft. and obvesually toe is the steering wheel and tire ware.

what was your caster ?
and of corse you cant get anyting fixed with loose parts in the front.
how are your leaf spring bushings

rover67
10-18-2011, 12:21 AM
my caster started out at just about a degree and I went to 4-5 degrees from there. the change in toe made the biggest difference initially, but after a little driving it went back to wobbling.

camber is about the same on both sides, about zero. That's not adjustable, but you know that. the axle tube is straight per my straight edge and several measurements with the digital protractor.

New bushings in the front, and new tie rod ends, and all new bearings in the axle. I rebuilt everything.

rover67
10-18-2011, 05:04 PM
New wheels on order from Summit, should be here by this weekend. I'm pretty convinced it is the wheels now since it has been driving fine today. I am going to put the straight two wheels on the front with the original tires and see how that does. But i need new wheels anyways.

http://www.summitracing.com/parts/SUM-85-5883/

rover67
10-18-2011, 11:00 PM
OK, Did some more work on it tonight...

I put the tall shackles back on with the new bushings. and put the straightest wheels on the front. I figure if it is indeed the wheels that were causing the death wobble the longer shackles will be alright (caster around 1 degree again).

I also noticed that the front hangers could use some beef, so I welded them up a bit better, and while I was at it I inspected the whole front end for cracks. couldn't find not a single one.

I also checked the torque on every nut and bolt on the front end. two of the nuts on the u bolts took some torque but nothing scary. everything else was typical Marco over tightened.

Last thing I did was go over the steering again. The steering gear box took a slight bit of adjustment but again nothing scary. It has been a lot worse in the past. I also tightened the tie rod ends to the max basically. they were close, but I figured I'd cinch them down good.

So that's that.

Tomorrow we'll see how she does. I still need to lower the bump stops again, that's about it. With the bump stops in the stock positions it rubbed somethin' fierce on the spooky night pre run. I need to just cut the front fenders out really. I'll get there soon, not just yet.

rover67
10-21-2011, 09:02 PM
New wheels got in today, heading to costco in the morning to have them swapped with my old bendy ones.

rover67
10-25-2011, 03:05 PM
New wheels took a LOT of the death wobble away, but it still shakes a bit at that magic speed. It just doesn't really start to oscillate like it used to which is a good thing.

I am thinking that maybe since everything else is brand new or replaced maybe it could be the steering gear box? I tightened it up and it felt really tight, but maybe something funky is going on with it?

I don't think it is a sticking brake caliper since the wheels and hubs are relatively cool even after prolonged driving (boulder to golden on 93).

TIMZTOY
10-25-2011, 09:23 PM
mabey its just your arms that are shaking every time you hit that majic number.. :lmao: JK.... "oh no 55mph holly crap hond on" :D

Rezarf
10-26-2011, 09:30 PM
New wheels took a LOT of the death wobble away, but it still shakes a bit at that magic speed. It just doesn't really start to oscillate like it used to which is a good thing.

I am thinking that maybe since everything else is brand new or replaced maybe it could be the steering gear box? I tightened it up and it felt really tight, but maybe something funky is going on with it?

I don't think it is a sticking brake caliper since the wheels and hubs are relatively cool even after prolonged driving (boulder to golden on 93).

Tires ;)

You can swap my fronts and see if it goes away.

rover67
10-26-2011, 10:24 PM
Hey man, i listened!!!!! I put the 40's tires on there and it aaaaalmost went away. feels just like it does now with new wheels.

AxleIke
10-26-2011, 10:46 PM
Like a said at breakfast, its time to get an assist on that beast. Guaranteed cure for death wobble.

PabloCruise
10-27-2011, 06:42 PM
Wow,
I was hoping to find a magic bullet in this thread, as my 40 has had a very intermittent for a while now that is frustrating me.
I'll keep reading here and start up a new thread I reckon!

rover67
10-27-2011, 07:18 PM
Wow,
I was hoping to find a magic bullet in this thread, as my 40 has had a very intermittent for a while now that is frustrating me.
I'll keep reading here and start up a new thread I reckon!

Yeah, I was hoping to find the same thing!!!

Well, Last night i checked the brakes, both calipers work great, nice and smooth. I went ahead and threw in some EBC Yellow stuff pads. Gonna try them. I also borrowed a steering gear box from Cardinal and threw it on there. No change to the wobblies.

I am starting to think it has to be the tires at this point and am getting depressed. Only weird thing is when I put the 40's wheels and tires on there it still had a hint of wobble.

I started looking at tires and looks liek the MTR's are on national back order which is a huge bummer. the BFG's are available all over the place though, but I am tempted to stay away from them due to the reviews....

Uncle Ben
10-27-2011, 07:32 PM
Yeah, I was hoping to find the same thing!!!

Well, Last night i checked the brakes, both calipers work great, nice and smooth. I went ahead and threw in some EBC Yellow stuff pads. Gonna try them. I also borrowed a steering gear box from Cardinal and threw it on there. No change to the wobblies.

I am starting to think it has to be the tires at this point and am getting depressed. Only weird thing is when I put the 40's wheels and tires on there it still had a hint of wobble.

I started looking at tires and looks liek the MTR's are on national back order which is a huge bummer. the BFG's are available all over the place though, but I am tempted to stay away from them due to the reviews....

Dont get me started on my anti km2 comments!::rolleyes::rant:

rover67
10-27-2011, 08:05 PM
Dont get me started on my anti km2 comments!::rolleyes::rant:

I know I know!! Other options are kinda limited though..... :rolleyes:

Caribou Sandstorm
10-27-2011, 09:45 PM
I think Romer and Nakman ran Toyos MT and had good results.

Uncle Ben
10-27-2011, 10:19 PM
I think Romer and Nakman ran Toyos MT and had good results.

Toyos are stupid heavy tires with a outdated BFG mudder clone tread. If oversize tires are part of the problem putting even heavier and wider profile ones back on is not going to solve the issue. :twocents:

nakman
10-29-2011, 01:17 PM
Toyos are stupid heavy tires with a outdated BFG mudder clone tread. If oversize tires are part of the problem putting even heavier and wider profile ones back on is not going to solve the issue. :twocents:

:blah: :blah: they also balance very well, and run very smooth, up to 40,000 miles.

corsair23
10-29-2011, 10:08 PM
:blah: :blah: they also balance very well, and run very smooth, up to 40,000 miles.

Agreed :thumb:

Although I also agree that they are stupid heavy like UB says but I love my Toyos :)

rover67
10-30-2011, 10:07 PM
well, we put about 1000 miles on the rig this weekend and I am starting to think it is the front springs.

The tires feel great at speed, and the front axle tends to feel like it's wandering under the truck a lot.

Maybe these are too flexy for what I like to do (hwy).

60wag
10-30-2011, 10:24 PM
add a sway bar?

ttubb
10-31-2011, 08:46 AM
well, we put about 1000 miles on the rig this weekend and I am starting to think it is the front springs.

The tires feel great at speed, and the front axle tends to feel like it's wandering under the truck a lot.

Maybe these are too flexy for what I like to do (hwy).

A bit late into this thread, but I have been following with interest.

Question: Are your front shackles reversed or stock? Terry

rover67
10-31-2011, 09:39 AM
Terry, Front shackles are in the stock locations... they are longer than stock though.

Bruce, I ran without a sway bar for a while and it was fine, both with the OME's and with these Alcans. I am thinking that the springs are allowing a certain amount of lateral movement of the axle under the truck. when at a stop on pavement if you move the wheel back and forth the wheels/tires don't turn at all, the axle just shifts back and forth.

Anyways, I got rid of my front sway bar a while ago, maybe I should have kept it, maybe I should go find another used one at the junk yard?? I wish I had more time before the maze trip. The sway bar is something I hadn't really thought about till you mentioned it.

Caribou Sandstorm
10-31-2011, 10:39 AM
Marco, if you call around and find one..I have a bit of a flexible schedule and could pick it up for you and drop off. Not a big deal at all.

rover67
10-31-2011, 01:00 PM
Thanks for the offers to pick up parts guys, I appreciate it.

I just ordered new OME's form Kurt along with a few sizes of axle shims from Roger Brown at 4 Crawler. Should all be here by the weekend. Kurt said what I am seeing is def. the trade off with soft springs.

rover67
10-31-2011, 08:25 PM
Holy cow I just set off on an internet search on Alcans and steering issues and holy hell did I get a lot of hits. Lots of complaints about wrong caster and loose steering... I have to believe that's some of what's causing my issues....

I can't wait to get the OME's from Kurt this weekend.

Jacket
10-31-2011, 10:31 PM
Didn't you have OME's before the Alcans?

rover67
10-31-2011, 10:56 PM
Didn't you have OME's before the Alcans?

Yes I did. It always drove fine with them till I broke them.

I went with Alcans to try something more custom made for my setup... I was looking for a longer spring with a bit more arch.

rover67
11-08-2011, 06:36 PM
Well, the OME's ride like a dream. I am sure they won't flex like the alcans, but with the lockers who cares. The truck really drives like a dream compared to what it used to. really unbelievable. No death wobble and it tracks straight and true on the hwy.

Anybody want 4" lift Alcans? I'll make you a deal.. I only paid like $500 for them plus another $200+ for the replacement they made me buy for the first one that broke. Nutty.

Now the truck is just back to being a little lower in the front. Time to cut fenders.

PabloCruise
11-08-2011, 07:02 PM
Good update!

So you think the wobble is completely gone?

rover67
11-08-2011, 10:37 PM
so far yes, it drives like a totally different rig. not even a hint of the wobbly.

Jacket
11-08-2011, 11:54 PM
What if you put another leaf in the pack to gain more height?

rover67
11-09-2011, 09:33 AM
done.. I think... i got the heavies from Kurt and added an extra leaf.. Maybe I need a tall leaf and what i got was more of a load leaf.

I'll call and ask.

Uncle Ben
11-09-2011, 09:49 AM
done.. I think... i got the heavies from Kurt and added an extra leaf.. Maybe I need a tall leaf and what i got was more of a load leaf.

I'll call and ask.

Longer leaves retain the most height and shorter leaves add load rating. The only way to really add height to a leaf spring pack is more arch. More leaves add some height simply because they add resistance to flattening.

Rzeppa
11-09-2011, 09:51 PM
Longer leaves retain the most height and shorter leaves add load rating. The only way to really add height to a leaf spring pack is more arch. More leaves add some height simply because they add resistance to flattening.

Interesting! That would explain why my rear leaf pack in my FJ45 has 3 really short overload leaves. That truck has 9 leaves in the pack in the rear, versus the usual 6 leaf pack you see on shorty 40s of the same vintage. It looks like they used the same 6 leaves as a regular 40 and then added 3 really thick flat (no arch) overload leaves at the bottom of the pack.

When I have the loader dump a ton of gravel or rip rap in the bed, it pretty much just smooths out the ride...;)

Alan Loshbaugh and I wrote back and forth about parabolic springs for FJ45s. He was a big proponent, and I was worried about load capability. I think a good alternative would be parabolics plus air bags. Run the parabolics straight up except when carrying a ton of rocks or logs in the bed, and when doing that pump up the air bags.

PabloCruise
11-10-2011, 02:19 PM
Since I have disks in the front I pull the wheels off. I have 2 pieces of angle iron that are straight and the same size. I C clamp them to each rotor using a level and ensuring each piece is centered with the hub the same on both sides. Then you just take the front vs rear measurements.

On my 40, after we converted it from a 40 axle to a 60 axle, ****** (name deleted to spare the guilty) forgot to adjust the toe-in. Since the 60 axle is several inches wider than the 40 axle, I had like 1.5" of toe-in. I also had occassional death wobble (which was a first for this rig). Needless to say there was excessive tire wear too. Once I reset the toe to 1/4" the wobble never returned and the vehicle is super stable at highway speeds, no wandering, etc. I'm beeting your toe in issue was the root of your problem, but as others have asked, how did it get so far out of whack?

Alright, I will admit my ignorance...

When measuring toe-in, where should this 1/4" difference be measured?
Randy describes measuring somewhere along some angle iron. I have heard you can measure the center line on tires. But if I remember my trig correctly (one of the things I remember from HS), 1/4" of toe at the end of a tire will lead to much different angle than 1/4" measured at the rotor.

I am betting the FSM has a perfect illustration that will make it all clear, but my manual is at home and I am at work wondering why I have this intermittant wobble...

AxleIke
11-10-2011, 09:15 PM
Alright, I will admit my ignorance...

When measuring toe-in, where should this 1/4" difference be measured?
Randy describes measuring somewhere along some angle iron. I have heard you can measure the center line on tires. But if I remember my trig correctly (one of the things I remember from HS), 1/4" of toe at the end of a tire will lead to much different angle than 1/4" measured at the rotor.

I am betting the FSM has a perfect illustration that will make it all clear, but my manual is at home and I am at work wondering why I have this intermittant wobble...

That is correct. 1/4" should be at the tire. 1/4" at the rotor will be a greater angle than that of the tire. On a trail only rig it won't matter. The 1/4" is ball park anyway. If you are concerned about it, take it to the alignment shop.

To back out the correct "at rotor" measurement, you need to find out the distance between your tire tread and the center of the hub. Call this distance TH (for tire to hub)

tan^-1 (1/4"/TH)= angle of toe

Then, measure the distance between your hub center and the rotor (call this RH.

RH*Tan(angle of toe) will give you the distance you should set your toe at when measuring from the rotor.

subzali
11-10-2011, 10:28 PM
From my experience, alignment shops get confused when you tell them that the only adjustment they can make is the toe-in, and they don't know the specs for the toe-in. From the FSM for an FJ40, there are two specifications:
For HR78-15B tire, it is -0.04 ~ 0.04 in.
For all other tires, it is 0.12 ~ 0.20 in.

I don't have a clue what that tire designation means, so I just took the measurement of my 31s and set it at the lower end of that range (1/8 in.) to see what it would do. It's not that hard to do with a helper to hold the tape measure. I don't have a problem with wandering or oversteer or anything, so I think I'm going to leave it.

PabloCruise
11-10-2011, 11:12 PM
Thanks guys.
I was thinking about this and wondering if the difference between my 33's and the factory 29's wass enough to be converned about...

rover67
11-13-2011, 06:13 PM
well, after putting some miles on it I am convinced, the rig is fixed.

And yes, adding the extra leaf didn't really add much height i realized, but it did a good job of keeping the front end from bottoming out on the rougher/faster sections of travel.

time to cut some fenders :)

Trapper50cal
11-13-2011, 11:26 PM
Glad you got er figured out!

subzali
11-14-2011, 08:12 AM
Careful, this is a family forum ;)

Trapper50cal
11-14-2011, 12:07 PM
:eek:

In all seriousness though, Marco. I'm glad that it isn't giving you trouble anymore. Corbet says you rally that thing 80-85mph with no regrets what-so-ever so it's a good thing that the front isn't shimmyin' around on you anymore.

rover67
11-14-2011, 03:50 PM
Thanks man!

Yeah, it is driving nice now :)

BreckBJ44
11-14-2011, 04:53 PM
Marco, Are you using the OME shackles? You can get a little more height with extended shackles and a caster shim (to keep the caster where it is now).

My Alcans had the same issue in the front (I have very extended shackles though). I have a 2.5 degree and they were still negative. Mine didn't have any wobbles, but it would follow ruts and bump steer. Either way yours must have been way out of caster spec.

rover67
11-14-2011, 05:09 PM
I played with the caster spec with the alcans and they didn't handle much differently. With my new OME's I currently have extended shackles with 6* shims which results in about 4* caster.

rover67
02-26-2012, 04:41 PM
well it looks like there is still some wobble. I thought I had it fixed but after i rebuilt my Power Steering Gearbox it came back in a big way. I finally gave up and threw a new steering stabilizer on there.. that made it driveable again. Now it just has a hint of wobble that won't grow to be full on death wobble. I've checked and checked and it all looks tight. even shot some video from underneath to see what was going on. I did catch it with some of the wobble, but couldn't see anything loose.

I am back to thinking tires now.

Didn't really get it to do it here:

http://www.youtube.com/watch?v=GzBbFsczgnI&context=C37310baADOEgsToPDskJ2e6wu6S8_lWu3YBySh-34

at about 1:20 it starts up on this one:

http://www.youtube.com/watch?v=gZDdEYnfxc8&context=C37310baADOEgsToPDskJ2e6wu6S8_lWu3YBySh-34

Always at an indicated 50mph.

nakman
02-27-2012, 10:02 AM
Gotta be tires- can you fit 35's on the 40? Or let me know if you want another set of jack stands..

Corbet
02-27-2012, 10:59 AM
Marco sounds like you need to borrow a set of wheels and tires from someone. If you were closer I'd let you have my 2nd set for testing purposes.

MountainGoat
02-27-2012, 11:07 AM
I have a set of 315 75 16 Cooper STTs mounted on 80 series rims. If they'll do you any good feel free to come and get them. Only temporarily though! :hill:

Uncle Ben
02-27-2012, 11:29 AM
Marco, I have the 80 e-test 265's and wheels stacked beside the garage if you need 'em too.

rover67
02-27-2012, 02:19 PM
Thanks for all the offers on tires guys, I appreciate it.

Let me figure out when I have some time and I'll work on it.

Also, Thanks Mr. Cardinal for letting me use your super fancy Go Pro to take the footage. I felt like a hero.

:)

Beater
02-27-2012, 04:22 PM
marco - you could do a rotate and see if that affects it.

FWIW, I have never seen tires cause a "death wobble" accentuate, yes, cause no. meaning, tires will cause a vibration, and the vibration or oscilation will then be transmitted to the steering via loose or worn parts. In re-reading since you and I spoke in person, I would say you had a cross-caster issue.

Now, cross caster, if severe enough, plus a slipped belt or balance issue on a tire can be pretty nasty, but that would still feel different than a "death wobble".

just sayin.. but it has been 15 years since I was in the tire business, so, you know, who knows.

rover67
02-27-2012, 04:47 PM
I'll do some reading on cross caster, not sure what that is other than maybe the obvious. I had it at DLS in Boulder and they checked the frame for straightness and said they were able to get the alignment dead on. they said that nothing looked loose or worn and that it looked "real straight for a rig with 304k miles on it" Now, I know I am missing something.

Uncle Ben
02-27-2012, 04:49 PM
I'll do some reading on cross caster, not sure what that is other than maybe the obvious. I had it at DLS in Boulder and they checked the frame for straightness and said they were able to get the alignment dead on. they said that nothing looked loose or worn and that it looked "real straight for a rig with 304k miles on it" Now, I know I am missing something.

Try messing with air pressures to Marco! Some times a tire can just get a wear pattern that likes to "walk."

rover67
02-27-2012, 05:27 PM
I've tried all kinds of pressures. from 12 up to 45 (accident)

at lower pressures the wobble is more dampened, at higher pressures it is more apparent..

I'll play around a little more.

PabloCruise
02-28-2012, 09:22 AM
well it looks like there is still some wobble. I thought I had it fixed but after i rebuilt my Power Steering Gearbox it came back in a big way. I finally gave up and threw a new steering stabilizer on there.. that made it driveable again. Now it just has a hint of wobble that won't grow to be full on death wobble. I've checked and checked and it all looks tight. even shot some video from underneath to see what was going on. I did catch it with some of the wobble, but couldn't see anything loose.

I am back to thinking tires now.

Didn't really get it to do it here:

http://www.youtube.com/watch?v=GzBbFsczgnI&context=C37310baADOEgsToPDskJ2e6wu6S8_lWu3YBySh-34

at about 1:20 it starts up on this one:

http://www.youtube.com/watch?v=gZDdEYnfxc8&context=C37310baADOEgsToPDskJ2e6wu6S8_lWu3YBySh-34

Always at an indicated 50mph.

Jinkees! That is a real bummer! :confused:

rover67
02-28-2012, 09:35 AM
well, threw another set of tires on ti last night and so far it drives well. I think I am going to remove the steering stabilizer and see if it is still gone...

Beater
02-28-2012, 12:49 PM
well, threw another set of tires on ti last night and so far it drives well. I think I am going to remove the steering stabilizer and see if it is still gone...

I think you have a slipped belt in one of the tires. Your oscillation/vibration was probably causing some serious steering feedback on top of your caster pull.

Uncle Ben
02-28-2012, 01:36 PM
I think you have a slipped belt in one of the tires. Your oscillation/vibration was probably causing some serious steering feedback on top of your caster pull.

I have my doubts on the slipped belt. I'm guessing the wear patterns on the tires are causing an oscillation. As the tires wear more the pattern gets more pronounced and resulting oscillation is getting more noticeable. A shifted belt wouldn't be harmonic...it would come on early and get worse as speeds increased.