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black95
12-01-2011, 06:54 PM
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Join Date: Aug 2008
Location: Woodland Park, CO
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Help with brake problems
Alright guys, I'm at the end of my rope on my rear brakes. This is my last ditch effort for help.

Here's the background: I've got a '95 4runner, SAS, V6 front calipers, FJ60 rotors. 7 years ago, I swapped in a chevy vortec 4.3, when doing that swap, I had to lose the anti lock brake thingy, whatever it was on the front passenger frame rail. Ever since then, no rear brakes.

Replumbed the system without the anti lock box, straight off the rear port of the master cylinder (closest to the firewall). no rear brakes. Swapped out the master cylinder, no luck. Swapped to FJ80 master cylinder, still, no luck. Ditched the LSPV completely, still, no rear brakes. Plumbed a whole new line straight down off the master right to the rear brakes, only a few bends -- yup, no rear brakes, at all, none, what-so-ever.

Used to live in Louisiana, so this was not too much of a big deal. Now I'm in Colorado snow country and it sucks bad. Front brakes lock up almost uselessly in the ice with no stoppage of the rear at all, and in 2 wheel drive, the rear will sit there and spin at stop lights, no matter how hard you're on the brakes. I know the rear brakes are put together right and the e-brake functions perfectly.

I give up, any ideas??? Anything??? I've been dealing with this for 7 YEARS...
I remember the front and rear brakes used to be tied together somehow, I was going to go that route next. Also wondering if there is something special about the rear drum's wheel cylinder, maybe it's a larger size and not getting enough fluid?

farnhamstj
12-01-2011, 07:12 PM
Disks or drums in the rear?

black95
12-01-2011, 07:45 PM
factory drums

TIMZTOY
12-01-2011, 08:38 PM
snap a pic. drums a super easy.. its either missing parts or both rear cylinders are bad.. could also have bad hose or 3 way.

take the hard line off the cylinder.
have someone pump the pedel one time.
do you have fluid ?
yes = bad wheel cylinders or hardware
no= clog or air in hydraulic line

Uncle Ben
12-01-2011, 08:39 PM
I see no mention of a proportioning valve. Early ABS took the place of the Prop valve and via sensors kept the brake bias in check. Drum brakes inherently require more fluid transfer as the pistons move out to brake and the return springs move the pistons back in when brakes are released. Disks do not move as much fluid as it is only the slight run out in the rotor that moves the piston back when not used. Proportioning valves accommodate this difference in fluid movement thus creating a balance of the brake bias front to rear.

TIMZTOY
12-01-2011, 08:43 PM
is the adjuster installed at the bottem of the brake shoes ? if not your never stop even it it looks and tests perfect

black95
12-01-2011, 09:38 PM
The system is bleeding fine, and if you leave the bleeder screws cracked, the fluid drips out on it's own, so I know they're getting fluid without restriction.

The adjusters are in place, on the correct side, and are self adjusting with the E-brake like they are supposed to. It's a real pain to get off my drums because they really need to be changed out and there's a pretty good ridge built up on them.

I think Kevin's on the right track, it's something to do with balancing the system. I know up front, the passenger front brake was somehow tied in to the rear system through a conglomeration of T's and elbows inside the passenger wheel well, before it went into the ABS pump. This has to have something to do with it. It's just so hard to believe that a two piston master cylinder won't work with independent front / rear operation, after all, that was the whole point. even if you lose one circuit, you still have some braking, unlike the old single circuit masters. :banghead:

There used to be an LSVP (Load Sensing Proportioning Valve) on the rear brakes with dual lines to the rear, one line from the ABS pump to the LSVP, one line back from the LSVP to the passenger wheel well brake line mess. I always thought the second line returning was only needed for the ABS pump to dump extra fluid. This is a '95, so there was only ABS on the rear.

This always gets me down about building your own rig, who the hell do you go to for help with this kind of thing??? I'm so disgusted with these brakes.

I'm going to take a look at the brakes on my '88 pickup tomorrow. Seems like I've done that before, but maybe that will shed some light on the situation. Thought about moving to an FJ60 master cylinder too, since they were made before all this ABS madness.

Uncle Ben
12-01-2011, 11:11 PM
The system is bleeding fine, and if you leave the bleeder screws cracked, the fluid drips out on it's own, so I know they're getting fluid without restriction.

The adjusters are in place, on the correct side, and are self adjusting with the E-brake like they are supposed to. It's a real pain to get off my drums because they really need to be changed out and there's a pretty good ridge built up on them.

I think Kevin's on the right track, it's something to do with balancing the system. I know up front, the passenger front brake was somehow tied in to the rear system through a conglomeration of T's and elbows inside the passenger wheel well, before it went into the ABS pump. This has to have something to do with it. It's just so hard to believe that a two piston master cylinder won't work with independent front / rear operation, after all, that was the whole point. even if you lose one circuit, you still have some braking, unlike the old single circuit masters. :banghead:

There used to be an LSVP (Load Sensing Proportioning Valve) on the rear brakes with dual lines to the rear, one line from the ABS pump to the LSVP, one line back from the LSVP to the passenger wheel well brake line mess. I always thought the second line returning was only needed for the ABS pump to dump extra fluid. This is a '95, so there was only ABS on the rear.

This always gets me down about building your own rig, who the hell do you go to for help with this kind of thing??? I'm so disgusted with these brakes.

I'm going to take a look at the brakes on my '88 pickup tomorrow. Seems like I've done that before, but maybe that will shed some light on the situation. Thought about moving to an FJ60 master cylinder too, since they were made before all this ABS madness.



I don't think the problem will go away with swapping MC's! Source out a Proportioning valve from an earlier truck or Cruiser. They are mounted on the lower bolts of the MC. Pretty easy plumbing and I think your rear brake will start to share some of the stopping duties. Right now your MC is doing it's job and one piston is clamping your calipers enough to stop the truck and that's all the peddle you can push.....while the rear piston need to travel further to apply the rear brakes but cant as it's on the common shaft as the front piston. If you tried a adjustable prop valve the results would be the same as you have now.

rover67
12-02-2011, 08:27 AM
I agree with Uncle Ben, a proportioning valve is definitely worth a shot. You need one especially in a pickup to balance things.

Also, you might look into putting in a residual pressure valve for the rears.... if they have heavy return springs the shoes might just be retracting far enough that a pedal push doesn't bring them back into contact with the drum.


Maybe the Anti lock box served this function in the stock setup and when you removed it you lost the residual pressure valve also. Trying to fix it you went with the 80 MC, but
the 80 MC may not have a residual pressure valve built in since it was on a truck that had disks in the rear.


As an FYI, I am using a T100 MC in the 60 which has runner fronts and stock rear drums and I also kept the stock proportioning valve. I think it has a residual pressure valve built in to the MC because the T100's had stock rear drums. It seems to work well.

http://www.summitracing.com/search/Part-Type/Residual-Pressure-Valves/Brake-Type-application/Drum-brake/?Ns=Rank%7cAsc

DaveInDenver
12-02-2011, 09:05 AM
The box you removed from the frame I think was the actuator. It should have had two brake lines and two power steering lines. The device I think would release pressure from the rear brakes when it detected lock-up and used PS pressure to push the brake fluid back.

When you took off the ABS box, what did you do to block off the brake lines? I believe one of the lines went to the 3-way junction block on the frame and the other to the LSPV in back. When guys remove the ABS they usually remove the actuator and just replace the hard line that ran from the actuator to the LSPV with one from a truck that did not have ABS.

You should not have to re-plumb the junction blocks on the frame by the torsion bar other than for the one line. AFAIK the systems were the same otherwise, same master cylinder, etc.

FWIW, the front port drives the front brakes and the rear port (by the booster) runs the rear. You can put a pressure gauge on the ports to make sure the MC is working, I'd have thought that if you plumbed directly from the rear port to the rear axle junction block that you would have brakes at least.

Uncle Ben
12-02-2011, 03:48 PM
http://www.familycar.com/Classroom/Images/Brake_System.GIF

black95
12-02-2011, 04:18 PM
Correct, The box on the passenger frame rail with the power steering lines is the box I got rid of. The two brake lines that went to it tied into the 3 way junction block behind the passenger front tire. Once the Box was gone, I just bent up a piece of line to connect where the two lines were removed... and then this whole thing came about :gaah:

I can't remember how my '95 used to be plumbed, but I looked at my '88 truck's brakes and it plumbs out like the crappy diagram I drew. I think the '95 ABS box interrupted line A.

Still curious to me that the front and rear system is tied together. Did the rear need more pressure than the rear master cylinder circuit could provide, was this just a place to dump unwanted fluid from the proportioner vavle, or was this there to balance the system???

Whatever the reason, I'm not putting the factory LSPV vavle back in because those seem to go bad anyway, and I don't know how you would regulate the system if you changed it to a Tee and had two lines to the back of the truck.

I'm thinking the internal 'circuitry' in the master needs pressure somewhere it's not getting. Been a while since I took one apart, but it seems like the rear piston pushes the front through fluid pressure. Seems like the rear would have to harden up before the fronts would kick in.

DaveInDenver
12-02-2011, 04:31 PM
I'm thinking the internal 'circuitry' in the master needs pressure somewhere it's not getting. Been a while since I took one apart, but it seems like the rear piston pushes the front through fluid pressure. Seems like the rear would have to harden up before the fronts would kick in.
Yes, the rear piston starts before the front.

black95
12-02-2011, 05:01 PM
Oh yeah, I thought about the pads being too far away from the drums, but they are for sure adjusted properly. Like I said, I have a hell of a time getting my drums off, and the dash mounted E-brake only pulls out about three inches. I think I'll take a drum off and ease into the pedal and see just how the pads are moving if I have time tonight.

I don't want to put the truck out of commission because this weekend and next weekend are our forest service volunteer weekends.

Please keep the ideas coming, I feel like there is some good knowledge with this group. The '79 - '95 tech forum guys had nothing :)

rover67
12-02-2011, 05:04 PM
the shoes don't have to move too much to take quite a bit of fluid. keep that in mind.

black95
12-02-2011, 06:04 PM
Alright, installed a lever style wilwood proportioning valve from another project last night, bled it after getting home from work... no dice. Just pulled the rear drums off (had to back off adjusters) and checked for movement, there is no shortage of that. My little 75 pound daughter pushed the pedal to the floor, and those pads move a lot, and the drum surfaces are shiny to show pad contact. Proportional valve makes no difference.

I'm starting to think about the front brakes now. There is no visible residual valve on the front. My thoughts as of now:

1) the rears are working, but don't have strength.

2) the fronts are not pulling away from the rotors for lack of residual valve and are working TOO well, or coming on too soon, or they are getting all the pressure through the master because the lines are not plumbed the way toyota intended.

Thoughts? I'm a dumbass?

black95
12-02-2011, 06:10 PM
proportioning valve. It's a lever style 8 position wilwood. Dirt track car style!! :) Yeah.... still don't work :(

That disconnected line is the factory line, the new line comes off the valve and bends around back under and down to the frame, can't really get a good shot of that.

Soooooo frustrating! This should be working!!!!

Uncle Ben
12-02-2011, 06:13 PM
Alright, installed a lever style wilwood proportioning valve from another project last night, bled it after getting home from work... no dice. Just pulled the rear drums off (had to back off adjusters) and checked for movement, there is no shortage of that. My little 75 pound daughter pushed the pedal to the floor, and those pads move a lot, and the drum surfaces are shiny to show pad contact. Proportional valve makes no difference.

I'm starting to think about the front brakes now. There is no visible residual valve on the front. My thoughts as of now:

1) the rears are working, but don't have strength.

2) the fronts are not pulling away from the rotors for lack of residual valve and are working TOO well, or coming on too soon, or they are getting all the pressure through the master because the lines are not plumbed the way toyota intended.

Thoughts? I'm a dumbass?

If the proportioning valve you just installed in only on one circuit it will only change the flow rate. If you use an aftermarket one it would need to in corporate both circuits! Like for example this one....

http://ecx.images-amazon.com/images/I/41IJWwJP3WL._SL500_AA300_.jpg

TIMZTOY
12-02-2011, 06:22 PM
Do the same thing you did with your daughter pushing the pedel. And the drums off. Now doing that push the pads back in while she's pushing. Trying to keep them from moving. Do the brakes win the fight or do you win the fight ?

If you win then you have a leaking seal somewhere

black95
12-02-2011, 06:54 PM
Man, if I can't get a standard brake system to work, I'll never get that damn thing to work... Looks like I'd have to re plumb the whole rig. I'm going to poke around some other rigs tomorrow on the outing. Particularly curious how the FJ60's are plumbed, and I know damn well my FJ40 is plumbed straight off the rear port, I'll use and FJ40 MC if I have to by God...

rover67
12-02-2011, 10:15 PM
My 60 is plumbed exactly like this:

http://www.familycar.com/Classroom/Images/Brake_System.GIF

TIMZTOY
12-02-2011, 10:20 PM
how are you bleeding it ? you could have a air bubble in it..

black95
12-04-2011, 07:48 AM
I looked at an FJ60 braking system yesterday and now I know what everyone was talking about with the combination valve under the master cylinder. I see now that this is my next route. Although, the 60 I looked at only had one line running down to the axle, so that is not going to work with my setup, I guess I could put a tee under it, but I would rather go aftermarket, since all of those valves I can get my hands on are 30 years old. Thanks for all the input, I think (hope) this will resolve my woes. Off to spend more money! :( I'll let you know how it turned out.

black95
12-19-2011, 12:12 AM
Even though I said I wouldn't do it, I sourced a brake combination valve from an FJ60. Have a friend in the CLC club that happens to have an old parts 60 behind his house, so I picked up the combo valve for the bargain price of a little beer. I decided on this because his FJ60 runs an FJ80 master cylinder with all stock lines and components, including a single line to the rear, with Stock 60 brakes up front, and GM calipers on the rear 14 bolt with a 2 pound residual valve. This setup is Exactly like mine, short of the drums in the rear. His brakes work great, you may have seen him on this year's Peterson's Ultimate Adventure video.

Unfortunately, I just got back from a test run on the very icy Rampart Range road, and the newly installed combo valve did absolutely nothing for my brakes. Not one ounce of braking from my rear end.

I'm gonna set this damn thing on fire.


I've had it... I quit... I'm done.... does anyone know an expert at this kind of thing? anyplace I can take this rig and NOT pick it up until the damn rear brakes work? I'm not talking about a guy you think might know a guy who may know a way... I'm talking about an EXPERT. Anyone, please?

black95
12-19-2011, 12:20 AM
newly installed combo valve.

rover67
12-19-2011, 08:46 AM
Yours has a residual valve? I didn't think I read that it does.

I am not sure who to point you to unfortunately, I am sure folks here know.

Uncle Ben
12-19-2011, 09:17 AM
Sorry that several of us are orwere onlybe SASE trained and certified and not proclaimed expert! Maybe you should call a radio show expert hotline!

black95
12-19-2011, 09:57 AM
Lol. Wasn't referring to the mud community, I've just had too many people tell me to take it to brakes plus... yeah, right. I didn't know you were sase certified, wanna fix this for me?:hill:

Uncle Ben
12-19-2011, 12:26 PM
Lol. Wasn't referring to the mud community, I've just had too many people tell me to take it to brakes plus... yeah, right. I didn't know you were sase certified, wanna fix this for me?:hill:

Hmmmm....looks like auto correct on my phone hacked up my post pretty good. :rolleyes: ASC would have been the correct acronym thank you! :o

Have you tried a very simple test of swapping the MC output lines port to port? Marco has a good reference to residual valves. A residual valve is in place on drum brake systems to help keep the peddle stroke shorter by maintaining a residual pressure (2-3psi) in the line to prevent the return springs from completely compressing the wheel cylinder each time the brakes are released. If your M/C is from a disk/disk setup it most likely does not have residual valves. If you can swap ports and nothing changes I think Marco gets the trophy!

black95
12-19-2011, 02:39 PM
Hmmm.... Interesting. I always thought residual valves were only for disks. I am running a disk/disk FJ80 master cylinder. That may very well make a difference. Seems like pumping the pedal would eventually make the brakes come on, I will have to try that.

Last night, I was running about 15 MPH and put both feet and my 275 punds of weight as hard as I could on that dang pedal, and nothing to the rear, pretty scary because that front end does nothing to stop this truck.

Keep the ideas coming! I love you guys man! :bowdown:

rover67
12-19-2011, 03:14 PM
The residual valves are for drums and some disks, but mainly drums. On slick surfaces can you pump the brakes and make it do anything to the rears if you pump fast enough? Even if not I'd still try a residual valve. they are cheap and at this point at least worth a shot I think. I think I put in a link to some in an earlier post. Most folks that run the disk/disk masters use them.

black95
12-19-2011, 04:20 PM
I think this is the answer. Marco, if you just fixed this, I'm gonna find you and give you a bear hug. :D I am finding 2Lb's and 10Lb's. What's the standard? 2LB?

black95
12-19-2011, 04:30 PM
Jeg's website says 2LB's for disks, 10LB's for drums.

Should I put a 2 LB'er on the front while I'm at it? Maybe that will make my brakes rock solid! I have always thought I had to push that pedal a little too far down to stop. Or does the 80 master already have a 2LB residual built in? :dunno:

EDIT: just read that you only need them for calipers if the master is below the calipers... How the heck would that be possible???

I'm so excited I think I'm gonna pee myself...:lol:

SteveH
12-19-2011, 04:47 PM
Some hot rods (1940s and earlier US-made stuff, in this case) have master cylinders near the floor that are operated on directly by the brake pedal. Some are below the floorboards. This is the only case I know of where the MC would be below the calipers.

rover67
12-19-2011, 04:48 PM
I wouldn't get too excited yet, it is kind of a long shot but maybe it will work. Seems like you've certainly checked everything else. Just get a 10lb one for the rear circuit.

Master can be lower than calipers if the application is a low race car with floorboard mounted master cylinder as well as older cars as mentioned above.

black95
12-23-2011, 07:06 PM
10LB Wilwood residual vavle... problem solved! :thumb: Awesome rear brakes now! Been driving around in the snow dialing them in, leased as punch about being able to stop without the front end locking up and diving into the ditch. :) Took out the FJ60 combo valve and put my proportioner back in, with residual.

That's just awesome, you guys rock. I've run this through everyone, including the main 'Mud forums, and nobody, I mean nobody had any ideas. :bowdown:

black95
04-15-2012, 08:45 AM
Well, 4runner's up to it's old tricks again. I ended up taking the proportioning valve out completely. now I have a line straight to the rear with a 10lb residual valve in it, and the rears work o.k. but you are way past front brake lock up before they start working. I wanted to run Black Bear this summer, that's why all the brake fixing. Don't want to run Black Bear with iffy brakes.

The 4runner's rear system is supposed to re-adjust when you use the e-brake, I think it works because they always seem to come in at the same place. I know %100 the rear system is put together correctly. Anyone know if you can run a 2lb residual in front/ inline with a 10lb? I've rear they make a 12lb, but damned if I can find one anywhere. Do I just have to be stuck adjusting my brakes manually every month? Never had this problem in any of my other vehicles.

rover67
04-15-2012, 03:33 PM
a 10lb and a 2 lb inline in any order will just give you 10 psi residual pressure at the brakes.

are you sure the adjusting mechanism is working well?

black95
04-15-2012, 10:51 PM
yeah, I even had the drum off and watched it work. I'm starting to think I might just need to replace my drums. As far as I know, they've never been changed and I think the wheel cylinder may be having to travel too far to make up for lost drum surface. Yanked on the E-brake hard a few times today and they tightened up a bit, enough that they're working again. I figured same thing on stacking residuals.

ttubb
04-16-2012, 07:24 AM
You do not have a residual valve on the front disk brakes, correct? IIRC they should not have a residual valve, only the rear drums.

nakman
04-16-2012, 04:41 PM
yeah, I even had the drum off and watched it work. I'm starting to think I might just need to replace my drums. As far as I know, they've never been changed and I think the wheel cylinder may be having to travel too far to make up for lost drum surface. Yanked on the E-brake hard a few times today and they tightened up a bit, enough that they're working again. I figured same thing on stacking residuals.

Why not twist that thing at the bottom then a few times to move the shoes out? What's worked for me has been I tighten that so it's next to impossible to slide the drum back on, then twist it back in a few turns with the screwdriver.. .somewhere between dragging all the time, and so much travel that they don't engage, is the sweet spot. are you out of adjustment?

rover67
04-16-2012, 05:14 PM
sometimes a really worn drum can make it harder for the cylinders to reach. take them to a place and have them measured before dropping the cheese on new ones though. it's nto worth buying new ones guessing.

black95
04-19-2012, 06:41 AM
No, I'm not out of adjustment length. That adjuster is amazingly long. Factory FJ80 master, no residual on front. I used to do the adjustment through the hole in the brake backing plate because there was a pretty heavy ridge on the drum that didn't allow you to put them together already tight. I took a grinder and flap wheel to that ridge, now I can slip them on nice and tight. :hill: Doesn't seem to matter though, they loosen up pretty fast. As soon as I'm caught back up with the money, there will be a disk brake conversion in my future.

TIMZTOY
04-19-2012, 07:52 PM
if your drums are beyond spec, anything you do isnt going to work 100%
there is a spec for a reason, not to just promote the sale of products. if you have a good sized lip or edge on the drum. your most likely way beyond the max spec.. i would start there. or........or........ take it to any shop for a FREE brake inspection !!!! :eek:

black95
04-24-2012, 06:14 PM
or........or........ take it to any shop for a FREE brake inspection !!!! :eek:

:D yeah, I know... Hate to do that though because I will not pay to have anything fixed... just the way it is. I'd rather mess it up and pay for my own lesson. That said, I would venture to say that %80 of "mechanics" in town are really "parts changers", and I really don't think they would know what to do with this much of a custom, pieced together truck. I'm a pretty dang experienced mechanic, and a great parts changer, having worked at a 4x4 shop for a while.

The thing is, you really have to understand how my parts work together, and why they do or don't... not just whether they're "good" or "bad", and I just don't trust anyone for that but me...

I recently rebuilt my own 700r4, cost me 500 bucks, and I put the 4th gear servo in backwards...drove to Arkansas once and it burned up after 3,500 miles :mad: Rebuilt it again, and it cost me 400. It's doing great this time... BUT, if it burns up again, I can rebuild it one more time, STILL for less than a shop would have charged me. Why wouldn't anyone try???

TIMZTOY
04-24-2012, 09:16 PM
:D yeah, I know... Hate to do that though because I will not pay to have anything fixed... just the way it is. I'd rather mess it up and pay for my own lesson. That said, I would venture to say that %80 of "mechanics" in town are really "parts changers", and I really don't think they would know what to do with this much of a custom, pieced together truck. I'm a pretty dang experienced mechanic, and a great parts changer, having worked at a 4x4 shop for a while.

The thing is, you really have to understand how my parts work together, and why they do or don't... not just whether they're "good" or "bad", and I just don't trust anyone for that but me...

I recently rebuilt my own 700r4, cost me 500 bucks, and I put the 4th gear servo in backwards...drove to Arkansas once and it burned up after 3,500 miles :mad: Rebuilt it again, and it cost me 400. It's doing great this time... BUT, if it burns up again, I can rebuild it one more time, STILL for less than a shop would have charged me. Why wouldn't anyone try???

ahh.. tru. but because its a free inspection. 60-70% of the time NOONE ever buys anything, and the techs dont really care, its kinda expected.. ( im a mechanic) you dont need to tell them anything special about your car other than the complaint thats hapening.. it is always, repeat ALWAYS good to have a fresh opinion. sometimes you just get so frustrated, from working on the same thing over and over, that you oversee the simple stuff.. hell it happens to the best of us at liest once every week.
if you dont tell them anything, and act like a dumb dumb that dosent even know what oil is. and get 3 inspections done form 3 diffrent shops.. then either they will have all found the problem. or at liest given you some good starting points..
you as a customer can always request to have there best diagnostic's person look at it. and ask that tech how long they have been turning a wrench. (you have the legal right to go out to your car when it's in the air)

P.S. at liest 5 guys at stevinson toyota west are all toyota offroaders. 4 of them all have crawlers, the other one is a daily driver taco. so just about nothing on there trucks are stock, and they all have upgraded brake systems. and the shop formen is a genius.

"it never hurts to have 3rd party opinions"