Hi everyone, ive been at this one for a month now.im on limmited funds but so far the symptoms are the brakes start to stick after driving for about 4- 10 min depends on the day no real solid pattern other that it does it every time. if i pull over and pull the booster vac hose the front rotors release. after a short distance it starts again. the pedal becomes hard but brakes really well. if i jam the brake pedal hard and fast repeatedly it lets go. ive replaced so far the pads the rotors the front flex brake hoses and ive flushed the system twice. id hate to waste money on any parts i dont need. granted the t4r is 20 years old and needed most of those parts replaced anyways but id hate to buy a master and it not be the problem or booster or calipers. my question is with this info can anyone take a good guess or an educated guess as to what my next step should be? is there a tried and true method to test the other parts?

 

anyone? ive searched this issue with mixed results. nothing concrete

 

man i got the same problem exactly with my 86 altho i did not know u can pull the vac line lol that will save me next time i have replaced every thing from booster to pedal to calipers and wheel cylinders no luck with flush or any thing new hoses etc....does any one know????

 

i have a 86 pickup.when i go on test drives my front calipers lock up to my rotors.i have replaced every thing from my pedal to my calipers to wheel cylinders to try and get this figured out.so every things new.they tend to stick 5-15 mins or averge 10 miles or when warm. whats causing this. i have my pedal height correct. all lines flushed im stumped any one please it would be great help

 

bump....

 

bump didy bump

 

bump da bumap

 

Did you bleed the LSPV?

 

yes i have the only thing i can think is is push rod or im just being dumb and missing something

 

You bleed the brakes the standard pattern? Any brake mods lately?

Nevermind...duh.

Do the rear brakes seem to lock up too?

 

Find the FSM and make sure the brake pedal and push-rod are adjusted properly.

 

So if you stop on the side of the highway, pull the check valve from the brake servo then replace it (bleeding out any vacuum within the servo), then without stepping on the brakes take off and drive 10-30 miles the brakes slowly start applying themselves up to the point where the fronts lock up and you can't drive?

 

all right big blue first... yeah i bleed them rear to front... no the rears dont lock they spin freely the fronts will lock so much its like brake torgueing the vehicle.ill have to stop and pull the booster hose or get water out of a ditch for the calipers to cool down enof to get home... abecedarian...what is fsm...and ur second msg is correct...

i went driving today and broke down no brake trouble cuz its so cold and not that far but anyways i stoped shut my truck off and now it wont start ill go to start it and it just makes a tunk noise from the starter battery is full... my key is really wobley in the ignition and can be pulled out does this matter?

 

Problem solved. it was the push-rod it was all the way out! looks like when the p.o. had the t4r the rear brakes went out they adjusted the push-rod to "fix" the issue. That explains why right after i rebuilt the rear brakes now the pedal had less travel. so i messed with it last night and now it rolls effortlessly! check that Push-rod! its really easy but remember to adjust the brake light sensor also.

 

This is how threads are supposed to go. Post up a problem and then the fix to help future searchers. I applaud you and I am glad you got it fixed.

 

heck yeah ill take a look into it

 

yodamudstar - I have seen old rubber brake lines cause a caliper to lock up on another make of vehicle, if you haven't checked yours, inspect them for cracks. I had very fine cracks in mine and a tire guy told me that could be a clue that the lines had failed internally. I was skeptical but followed his instruction and the problem was fixed! He indicated that essentially the hose was allowing fluid in under pedal pressure, but would colapse internally once pedal pressure was gone and not let the fluid back out, thus locking the caliper.

 

wow thats a great idea and makes alot of since ty i will look into it cuz i still havent figured it out im still stumped but got hope now lol ty

 

Good luck, let us know how it goes...

 

is there bigger calipers that can just bolt up to my truck