Just did lockright locker in the rear of my 89 4runner sr5 4cyl had to disconect the brake line fitting from the axle to put that in after that was done i re-installed everything. Bleed my brakes and pedal was extremely low. i figured i would just rebleed the fronts as well to remedy this in that process tried the brakes again this time the pedal would sink then id have to pump to get normal braking pressure.bleed the brakes 2 more times and no change.so i decided to replace master cylinder and didnt do a thing. i double checked my fittings seems tight and i dont see any fluid dripping anywhere.im guessing it could be a really small leak somewhere im not seeing but im stumped anybody have anything they could add so i can fix this?

 

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yea followed that pass rear.. dr... pf... df... lspv... still didnt help. i cant think it would be booster diagnosed that and it seemed fine and i cant imagine that having any effect on the pedal sinking

 

my truck is doing the same thing. its had low brake pedal for over a year now, ive replaced every part except the lspv. ive lost track of how many times ive bleed them. just waiting for some one to post up a new solution to try. i should add that if i disconnect the vacuum to the booster and reconnect i get good pedal some times but it only lasts for a couple of times.

 

it doesnt make sense how they can work good and overnight they mess up im ripping my hair out thinking about it. gonna try messing with the star adjuster tomo to see if that has any effect on the system if not then the rubber lines, ive had them collapse on me. after that im replacing the all the lines calipers and wheel cylinders if succeed ill let you know and im still open to suggestions if anybody has any

 

If you had good brakes before you took things apart it has to be something you did.

Did you need to back the brakes off to remove the drums??

Did you readjust them??

If you only broke the brake line in one place then you got dirt in that fitting allowing it to pull air in it does not take much.

They can draw in air and not leak fluid and will tend to drive you nuts as you are finding out.

Another thing after all this bleeding one or more of the bleeder valves could be doing this!!!

 

Initially i replaced the shoes in both drums i was gonna replace both wheel cylinders as well since one was leaking. Fixed the leaky cylinder problem was the leaking cylinder. i didnt correct it at the time since i knew the brake line was snagged up (and didnt have a break line)with the screw so i left it and replaced shoes no problems till the locker. I just did replace the wheel cylinder on the opposing wheel and line now all hell has broken loose. I have no adjusted anything really besides the side of the fresh wheel cylinder and i repaired my parking brake sorta im thinking of disconnecting it cause this maybe the cause too because it was seized till i did this

 

Im getting too long with my answers but heres the run down
Did you need to back the brakes off to remove the drums??no never touched the star adjuster

Did you readjust them??nope only touched the parking brake because it was seized and the clearnce between the screw there is big inch or so inbetween

If you only broke the brake line in one place then you got dirt in that fitting allowing it to pull air in it does not take much.
They can draw in air and not leak fluid and will tend to drive you nuts as you are finding out.

Another thing after all this bleeding one or more of the bleeder valves could be doing this!!![/QUOTE] thank you for this bc now im gonna replace both lines and brake cylinders and see the only thing i see is weird is front brakes and rear should be at least 60-40 ratio even the front feels odd im new to the whole brake systemkinda but never had a problem with them besides seized caliper and line but do u think i should start there?

 

First off in Toyota Vehicles the use of the Emergency brake is what keeps the rear brakes adjusted.

If you don`t use the emergency brake the rear brakes are soon out of adjustment . Which means ever increasing pedal travel

It sounds like your brakes are a mess when you changed the rear shoes did you measure the drums?? Perhaps you replaced them but did not mention them.

Just how are you bleeding your brakes because of the LSPV that controls the brake bias it can take very long to get all the air out.

All I can say is take your time.