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View Full Version : Borrow Stock Spare 80 Series Rear LCA's?


Nay
02-28-2009, 11:33 AM
I am looking to borrow for a week or so a set of stock 80 series rear lower control arms if you upgraded and have a set sitting around.

I am cutting and sleeving my first gen Slee arms to lengthen them to fix pinion rotation and to move the wheelbase back slightly for when I go up to 37's rather than by adjustable UCA's that don't also help wheelbase and cost a fortune, and I'm looking for some backup in case I run into a hitch, 'cause once I cut 'em there's no going back on the rig until the project is complete.

Thanks!

nakman
03-01-2009, 08:50 PM
Sorry Nay, I looked but I must have tossed them :confused: I found my set of uppers if you want to hack at those for some reason.

Uncle Ben
03-01-2009, 09:01 PM
Hmmmmm....I missed this thread somehow.... Nay, I have my stock set in the corner of the garage collecting dust. You are welcome to use them if ya want.

Bikeman
03-01-2009, 10:04 PM
Why not go with adjustable upper UCA's? It has helped my wheelbase the same and set the pinion up for a DC shaft and gets the pinion up out of the way. My UCA's are an inch or more longer helping my wheelbase that got reduced with a 5.5" height increase. You'll have to lengthen and re-tube your drive shaft anyway if you stretch your wheelbase much. What's a little more to find a DC out of a Tundra like mine? No Spicer crap here. Plus, you get the blue bushings that flex more and are not polyurethane. Or, get the weld-in adjusters if you don't want to help the economy as much:hill:.

If you lengthen the LCA's, won't you drop the pinion angle more? Your pinion flange and U-joint will be kissing rocks. Keep in mind the output flange at the TC is at 4 degrees, and your U joint angle at the pinion may not match, resulting in vibes.

Beater
03-02-2009, 06:51 AM
do it right and add the addjustable uppers and lengthen the lowers. Instead of sleeving, run .25 angle on the bottom of them. The point of the angle will act as a ramp on certain obstacles...

oh- and schd40 is almost a perfect match for the stock rear arms.

j

Nay
03-02-2009, 05:56 PM
Hmmmmm....I missed this thread somehow.... Nay, I have my stock set in the corner of the garage collecting dust. You are welcome to use them if ya want.

Appreciate it, welding them up tomorrow so don't need a set unless something goes horribly wrong :hill:

Here's a perfectly good Slee 1.75" OD .25" wall chromo arm cut in half, and then sleeved in 2" OD .120 wall DOM. :D

Nay
03-02-2009, 05:57 PM
do it right and add the addjustable uppers and lengthen the lowers. Instead of sleeving, run .25 angle on the bottom of them. The point of the angle will act as a ramp on certain obstacles...

oh- and schd40 is almost a perfect match for the stock rear arms.

j

Not stockers - this are the HD Slee first gen arms.

Nay
03-02-2009, 06:55 PM
Why not go with adjustable upper UCA's? It has helped my wheelbase the same and set the pinion up for a DC shaft and gets the pinion up out of the way. My UCA's are an inch or more longer helping my wheelbase that got reduced with a 5.5" height increase. You'll have to lengthen and re-tube your drive shaft anyway if you stretch your wheelbase much. What's a little more to find a DC out of a Tundra like mine? No Spicer crap here. Plus, you get the blue bushings that flex more and are not polyurethane. Or, get the weld-in adjusters if you don't want to help the economy as much:hill:.

If you lengthen the LCA's, won't you drop the pinion angle more? Your pinion flange and U-joint will be kissing rocks. Keep in mind the output flange at the TC is at 4 degrees, and your U joint angle at the pinion may not match, resulting in vibes.

I need to drop the pinion - I have vibes from it being raised by lifting, because the pinion raises with lift (due to unequal UCA/LCA arm length) and reduces net effect of operating angle on the axle end while angle is increased due to lift on the t-case end. I am about 5 degrees of operating angle misalignment on the two ends of the shaft, hence the vibes.

The reason I am not going adjustable UCA plus DC shaft is that is about $900 total off the shelf cost to my door vs. a couple of pieces of DOM sleeve and paying a buddy for some welding time. Adjusters are quite expensive and still have to be welded in, and by going this route my UCA wall thickness goes to 3/8", and doesn't affect my other metric to shift wheelbase back. 5/16" won't require the rear shaft to be retubed.

UCA's do not affect wheelbase materially. Raising the pinion up for a DC shaft would raise the LCA mount around the axle centerline as defined by the LCA and creates a very minor shift, but nothing close to the degree of lengthening the LCA's.

You have to lengthen the lowers in order to restore wheelbase to stock - this occurs at 5/16" increase over stock, because as you rotate down you pull the LCA mount about 1/16" forward, which counters the 1/4" increase in length you need to return to stock wheelbase (think Pythagorus and his theory for that calculation). This 1/16" shift would also be close to the net effect of wheelbase lengthening by UCA lengthening, because wheelbase shift can only occur as the eye of the LCA mount rotates around the centerline in an arc defined by adjustment of the UCA.

The net of my approach is twofold - you return pinion angle to stock (and yes, slightly closer to the rocks) to proper alignment and you shift the rear tires slightly away from contract for >35" tires to where you can trim for clearance, which I already have. If I decide to go DC in the future, I still have the wheelbase I want.

The Slee blues don't flex more than stock, the Toyota rubber bushings allow massive flex you will never get out of any solid plastic bushing, no matter what the material, because of how the rubber is designed with pockets to allow maximum deflection. It may not be material for normal usage, but I would put rubber back in any of those arms, personally.

I have always wondered why for bigger lifts somebody doesn't produce a slightly longer LCA - you'd save your customers a fortune because rather than selling them an adjustable UCA you could give them a heavy duty LCA they want anyway.

This won't work for mudflap shod rigs because you are off centering the tire slightly to the rear and may create contact, but for a rig like mine it's perfect.

Hey, this turned into a tech thread :D

Bikeman
03-02-2009, 07:42 PM
Good show. With bigger lifts though, the U joint angles may be too severe, which is what I originally did. I made my U joint angles the same (lowered pinion) with the adjustable arms on a rebalanced shaft with new U joints and got vibes (5.5" lift), so that's why I had to then roate the pinion up and go the DC route. I had U joint operating angles in the neighborhood of 11 degrees +.

Beater
03-03-2009, 06:45 AM
I did the same to both my 80's. Other added benefit is lowering of torque steer effect.

good on ya.

sleeoffroad
03-03-2009, 09:17 AM
The rear tires move backwards when compressed, so you increase the rubbing issue when you move the axle back.

It is also really difficult to supply 1 length arm for everyone and adding an adjuster to the bottom arm is difficult due to potential damage. The adjust makes it possible for people to go both ways, either DC shaft or not.

the wheel base is an issue, but if you use front arms that actually move the axle forward (instead of caster plates) then the net wheelbase on the truck is not that much different from stock.

Beater
03-03-2009, 01:53 PM
I was wondering what took you so long on this topic....

lol

Nay
03-03-2009, 07:20 PM
The rear tires move backwards when compressed, so you increase the rubbing issue when you move the axle back.

It is also really difficult to supply 1 length arm for everyone and adding an adjuster to the bottom arm is difficult due to potential damage. The adjust makes it possible for people to go both ways, either DC shaft or not.

the wheel base is an issue, but if you use front arms that actually move the axle forward (instead of caster plates) then the net wheelbase on the truck is not that much different from stock.

Agree, this only makes sense for me because I am trimmed up heavily on the lower rear quarters and flareless, so going to 37's a slight adjustment to the rear is going to be favorable if I need a bit of extra trimming vs. trying to trim to the front. By the time you are on 37's you are probably close to 3" of bumpstop drop so that full stuff arc up into the wheel well is reduced.

I don't think I'd want an adjustable lower, those arms take some abuse on an 80 and I agree you'd probably damage the adjustable mechanism.

Anyway, we did this today and ended up about 3/8" longer than stock with perfectly equal u-joint angles. It is whisper smooth, about 8 degree u-joint operating angles, which is starting to get a bit high in terms of joint wear, but those Koyo joints just seem to go and go.

We also built some sliders from the frame to the LCA frame mount, which is a huge hangup point on the 80, out of 1/4" stock. Now it should be able to slide up over that mount (to a degree, anyway), and the mounts are fully protected.

I'll post some pics tomorrow. Great mod :thumb:

sleeoffroad
03-04-2009, 07:09 AM
FWIW, I have had 37's on a couple of 80's and never rubbed on the front of the wheel well, even with flares.

Uncle Ben
03-04-2009, 07:24 AM
FWIW, I have had 37's on a couple of 80's and never rubbed on the front of the wheel well, even with flares.

Off topic but I gotta comment..... Christo, I think it's creative that you had 'Roots dash lights on in your signature banner whereas the ad banner has them off. Nicely done.... :thumb: ;) :lmao:

Nay
03-04-2009, 08:26 PM
FWIW, I have had 37's on a couple of 80's and never rubbed on the front of the wheel well, even with flares.

Yea, honestly, I think I have room all around. I just didn't want to pony for new uppers. But here is my 35" trxus stuffed on 2" stops before I trimmed those lower rear quarters up. You can see the stuff is slightly to the front of the wheel well, so I think it's probably perfectly centered now.

Playing with millimeters here at the end of the day, what I mostly achieved was to be the first person to cut a perfectly good set of your arms in half just to fix a pinion angle problem. :hill: