'88 brakes issue

[yotason]

Hey, i have a '88 toyota pick-up, 22re engine, 4wd. I got it for free from the roadside, needed a fuel pump and the person just left it there. their loss, my gain. anyway, so i restored it, wooden bed, its been a good project and ive gotten to the point where im jut fine-tuning it a bit. the biggest thing that i can't figure out has been the brakes. I have bled them and bled them, replaced the master cylinder, replaced callipers, bled and bled and bled. the brake pedal still goes to the floor on the first pump, second pump it has a little resistance at the end and third pump its almost all the way there. there is no way there is air in the line, and i am wondering if anyone has any ideas? i thought it might be the adjuster for the weight that is under the bed, since i have a wooden bed it might not be giving my rear tires enough fluid?

[whomadewho]

The (adjuster) does it have brake lines going to it,and a rod going to the carrier assembly?? If it does there is a bleeder screw on it,and it needs to be bleed. When you loosen the bleeder screw and no fluid comes out - Grab a hold of the rod,at the end of the ( adjuster) and SLOWLY move it up and down until fluid comes out. Are you sure the vehicle is a 1988? The (adjuster) is part of the ABS. I may be wrong but I did not think the system was not used until 1990.

[yotason]

well i have bled that screw a couple times but never while moving the rod, oh and yes it does have a rod going to the assembly. anyway i will try that, the other thing i noticed after i posted this is that the drivers side drum brake refuses to work until the third or fourth pump of the pedal, maybe that would assist in the diagnosis? and i checked the haynes manual to see if the adjuster is a part of the system used in 88s and it is in there so maybe it started with the 88 pick-up? no idea.

[whomadewho]

The brakes WILL NOT WORK unless you get that valve bleed. There is a diaphragm in the valve,that is the reason for moving the rod SLOWLY up and down. The driver side drum will not work until the valve gets bleed. When you use the hand brake - Thats how the rear brakes get adjusted. There is a adjustment on the backing plate for the hand brake. If the adjuster is froze,this MAY make adjusting the rear brakes more difficult. When bleeding the valve do not be afraid to pull on the rod. What type of bleeder are you using?

[yotanut7]

That adjuster is for weight, more weight = more rear braking power. Not part of the ABS, toyota used that for a long time. My 87 has it. Have you checked the level of your brake fluid? It could be possible that you have bled too much out and there just isnt enough left

[DeadlyPeace]

Things to check for:
Worn brake pads and/or shoes
Worn Drums
Leak in brake system
Air in brake system
Master cylinder faulty – Did you bench bleed the new one?
Rear wheel cylinders faulty
Rear brake adjusters faulty
Bad fluid – Should be kind of clear, almost transparent. If it is turning brown, the fluid may be beyond its useful life.

The proper order for bleeding the system is to start with the longest hydraulic line and work around the vehicle to the shortest line, and then do the LSPV (Load Sensing Proportioning Valve – or the adjuster with the rod) last. So in this case, the order is: driver's rear wheel, passenger rear wheel, passenger front, driver's front, LSPV.

To bleed the brakes, pour some brake fluid into the drain can, and immerse the end of a tube (clear if possible) in the fluid. Remove the rubber nub from the bleed valve and put the bleeder fitting and hose on the valve. Crack the valve open until a little fluid begins running in the tube, then begin pumping the brakes. Watch that the master cylinder doesn'trun dry and the condition of the fluid in the rubber hose. When clear fluid is streaming through the hose and no air is present, close the valve and proceed to the next wheel. Top off the master as required.

Once the brakes and LSPV have been bled, check the system for air. Start the vehicle and step on the brake, then kill the engine and hold the pedal down. If the pedal does not sink after 15-20 seconds, the system is airtight. If the pedal does sink, the system should be bled until it is airtight.