Kevinshoemake3

Hey everyone, I need a little help with a brake issue I am having on my 85 4x4 pickup. The truck had been sitting about a year when I got it. I got it for 900 dollars and all it took to get it going was a battery. I got the truck running, and I had problems with the rear end locking up. For example, the rear end will completely lock up even at speeds of say 30-40mph when I push the brakes. I replaced the front brake calipers, master cylinder, and brakes pads in the front because I felt the truck needed all the above to be safe on the road. I attempted to adjust the drums (you know at the adjuster on the inside of the drums) with no success. If my drums needed to be replaced they wouldn't lock the rear end up would they? Do i need to adjust the proportioning valve? Anything else I should check? I do not have any drum brake experience really so I don't have any information or ideas to fall back on. Thanks for your help.

Kevin

the_supernerd

Are both rear wheels locking up or just one? Both wheels locking up could be the proportioning valve, while one wheel locking up would be something else. Take the drums off and inspect the rear brakes. If the calipers and the master cylinder needed to be replaced, then the rear brakes probably need some work.

brownbagg

its that prop valve abouve the rear axle, if the truck as a lift on it and the valve wasnt raise it lock the wheel up. alot of people remove the valve and add an adjustable wildwood or russell valve.

4Crawler

iTrader: (3)

Actually, a lift will trick the LSPV into thinking the bed is very light and that will cause it to lower the rear brake pressure. The bed/frame has to move closer to the axle to make the LSPV think there is a lot of weight in back in order to raise the rear brake pressure.

Could be the sensing arm has been cut off or removed from the LSPV and that will typically let it rise up all the way raising the rear brake pressure to the maximum:
- http://www.4crawler.com/4x4/4R_suspe...ortioningValve

desertcamper67

Is there any visible fluid on the backing plates? An axle seal leaking gear oil on the shoes can cause lock ups.
You need to take the drums off and take a look. Don't be afraid of things falling off in there. If that happens when you take the drum off it seriously needed attention anyways.
We'll get you through the drum brakes. Piece O cake.

Kevinshoemake3

Hey everyone, thanks for the help. I inspected the rear brake yesterday, and decided to go ahead and change brake shoes, wheel cylinders, and all the springs. Still have the problem, but I am going to work on the proportioning valve next. I probably will just replace it with a valve like brownbagg suggested. Gotta be getting close, haha, I am fixing to have a brand new brake system. Both wheels are locking up. Thanks for your help guys.

Kevinshoemake3

Yeah, drum brakes are a beast I had never really attempted before. I have rebuilt a 22r, and just about everything else on Toyota trucks, but this was a first. I guess I had been lucky so far.

Alter Ego

i feel your pain with the rear brakes. my passenger side was making a grinding noise in reverse, took off the drum yesterday, and half of the brakes fell out. the whole front drum pad, had pulled out from the axle and was rolling around loose inside.

4UNER

Can anyone tell me the difficulty level for removing the exhaust manifold on a 94 4runner v6 3vz-e. I don't mind doing the work.

DoveGray85

Wow! That was off the wall.

Drum brakes aren't too bad if you have the right tool for installing the springs. That's the key.

betovetto

Hey everyone! Im just having like the same problem right know. Im new here so i dont know if y have to open a new post, or hear is just find.
The problem I have is with my 4runner 85, rear brakes.
It happens that when I push the brakes, the rear wheels completely lock up(in most of the cases is only the driver side)
I have all ready replaced the front brake calipers, make service to the master cylinder, brakes pads in the front, change the proportioning valve to an adjustable valve, and check the rear drums but everything its ok.
And im having the same problem since i bought it, I don't know what cold be the problem, if someone just cant help me im going to appreciated! Thanks for your help.

rokblok

iTrader: (1)

Check for rear brake shoe contamination(gear oil due to bad axle seal, or leaking wheel cylinder), check hardware and brake shoe condition, check adjustment of rear brakes and park/emergency brake system.

Bigblock

I dont think your front brakes are working at all. Plus the rear drums are rusty,soaked with oil/brake fluid.

sea dawg

A brake related question on my 85 truck. I've been having several problems with the brakes. Very stiff pedal with little brake effect, and when you apply them abruptly at 20-30 mph, the steering wheel turns left and the truck pulls to the right.

I replaced the booster (was surging with repeated application of brakes) and the master cylinder, and am left figuring that there must be something wrong with the front calipers.

Since my pocket book is spent on subsidizing the various upgrades for off road mods, I just want to make sure I'm throwing money in the right place.

Thanks in advance.........

4Crawler

iTrader: (3)

Stock steering box and other parts? If so, is the stock torque rod still installed and the bushings in good shape? If not, that might be causing the "brake steer" problem. That torque rod helps to prevent the front axle from rotating under braking forces. When that happens, the steering J-arm on the driver's side pushes forward into the draglink attached to the steering box/pitman arm causing the wheel to turn left and the truck to turn right.

Two fixes, 1: fix or reinstall the torque rod or 2: Cut off all the stock stuff and put in cross over steering, no more torque rod and no more brake steer.

That be the torque rod, visible just above and behind the draglink:

sea dawg

Much appreciated. Cut off the drag link when we put the gusset on the front axle Getting ready to do a RUF install with high steer. Sounds like that will take care of the issue.

Making a last run or two before the trails close for the season here in Central Cal. Then finishing the build over the next couple months. ( Marlin crawl box, 63's in back, RUF, high steer, lunch box lockers front and rear , IFS rear axle and steering box- that's all I've got in the pocket book right now!?!)

JanK

I could use some advice on my 1985 22R pickup (low mileage, originally a fleet vehicle, still has mostly original parts). The brake system has been contaminated with oil and I am trying to figure out, first how this may have happened and, then just how much of the system needs to be replaced.

Is it possible that the system was contaminated when I accidentally left the oil filler cap off and drove it that way for a day last week?
Can the oil spray have found it's way in through some failing part around the booster, master cylinder, or Proportioning valve?
The power booster did seem to be affected when the oil cap was off. Could it be that this was due to a loss in the vacuum system? And could that have, then lead to the contamination?
Could the brake system fail in less than two week's time from such an error? Or maybe someone at the last oil change topped it off with the wrong stuff back in July?

Also, I understand that the oil will and/or has deteriorated all of the rubber in the system; but have several questions in how to get the system back to safety:

1- Can the system be effectively cleaned by changing out all the rubber parts and then flushing it out with brake fluid?
2 - Does the Proportioning Valve have rubber parts? I'm not sure if my truck even has an LSPV - can't find it where I expect it to be from reading other posts on this site.
3- if I do need to replace the Proportioning Valve, does anyone know where I can find one?
4 Will the power booster system also be affected or is it isolated from the fluid?

ANY encouraging thoughts, advice, or resources would be greatly appreciated. This is my "dream truck" and I want it to last!

sea dawg

I'm a relative newbie at this stuff, but I would be surprised if enough oil could accidentally find it's way into the brake hydraulic system to cause much trouble? The power brake booster is driven by vacuum, and is not involved with the brake fluid. The proportioning valve in the back is a long ways from the master cylinder, and even if you were flushing the system, it'd take some work to get new fluid back there (this is part of why I'm skeptical about engine oil ruining the proportioning valve)

If you need a used one, there is a special yard near here that ships parts. they're called TAP and the web site is.

http://fresno-taprecycling.com/index...mation/contact

the_supernerd

I doubt oil could have got in there by leaving the oil cap off, assuming the brake fluid reservoir cap was still on. Someone could have put oil in it by mistake, which I am sure would cause problems, but I am not sure exactly what. Rubber parts could have just been ready to fail since they can dry out over time, even on a low mileage vehicle.

If you want to be certain everything is in good shape, then go through the braking system and inspect everything. More than likely you will end up replacing most of it just due to the age of the vehicle. Wheel cylinders, calipers, hoses, and a master cylinder are not too expensive if you do it yourself. Either way, get all the fluid out of the master cylinder reservoir (or replace it), then bleed the brakes really well to make sure all of the oil is out of the system. You could probably blow out the hard lines while everything else is removed to be sure the oil is out.

The load sensing proportioning valve is in the rear of the truck and has a rod attached to the rear axle and needs to be bled, also. I have seen some trucks without the LSPV, and just a standard proportioning valve under the master cylinder. That one does not need to be bled.

Terrys87

iTrader: (1)

If the fluid is not changed as needed, over the years the fluid breaks down and corrosion really makes a mess in the lines. I disconnect the lines at the Master Cylinder, calipers and slave cylinders and use an air hose to blow the lines out. Lots of yucky stuff comes out. In some situations I fill the lines with Marvel Mystery Oil for a day or so and blow them out again. Then flush the lines with brake fluid.

You booster is isolated from the fluid. A leaking Master Cylinder can get on the front of the booster but I have not seen it enter a booster and cause damage from my experience.

Unless you have some rubber lines that are needing replaced I would flush lines, replace master and slave cylinder, turn rotors or drums with pads if needed and you should be ok.