Adawg_08

Well my brakes were getting pretty bad. No brake unless you pumped it. So I put a new Master Cylinder on it. Bench bleed it really good and ran a quart of fluid thorugh all the lines. Same thing, you have to pump at least once to get much brake, then it still goes to the floor. Lines are good, no leaks, fresh fluid. What else could I do? I'm pretty sure that there is no air in the lines. I have a one man bleeder but still used 2 people. I will try gravity bleeding them tommorow, or I can get a hold of a power bleeder to try to. I bleed each wheel and the LPSV. I can't drive it because brakes are to bad.

What do think is wrong? Please help me.

CJM

Your brake booster is most likely bad.

However you check yor discs and drums out and they are fine right??

UncleBob

Rear Brake shoes adjusted 'till they scrub the drums, right?

PoleVaulter95

i have a similar problem so i cant wait to see what the out come is how do u know if your booster is shot or your shoes arent adjusting all the way?

UncleBob

http://personal.utulsa.edu/~nathan-b.../3checksan.pdf

http://personal.utulsa.edu/~nathan-b...tem/11-4wd.pdf

gonzo

X2
Misadjusted rear shoes will cause this.
I find the almost everytime I go wheeling, (mud, water) my rear shoes are out of adjustment.
Back off on the adjustment for your e-brake then adjust the shoes and readjust the e-brake cable
Good idea to pull the drums first and check the shoes and clean out any mud etc.

PoleVaulter95

uncle bob those are some great sites you posted i think the will help me out and hopefully they will help adawg 08 good posting

UncleBob

Here's the whole manual. Yota-tech is great, isn't it?


http://personal.utulsa.edu/~nathan-b...fsm/index.html

jmach1

When you say you ran a quart of fluid throught the system I am assuming you meant that you ran brake fluid through it. The reason I ask is that about 3 years ago, stupid me forgot how to read and put power steering fluid through the entire system. Could not figure out why my brakes sucked and that the brake reservoir cap kept falling off. Thanks to this forum, I figured out what I did and replaced almost everything. That is just my 2 cents and I hope that was not what you did. I really dont think thats what you did but it can and has happened.
JMach1

Adawg_08

I am pretty sure the booster is good though. I did that test with the engine off and the pedal got higher each time.

91TPU

pull the the brake booster vacuum line while its running, make sure nothings wrong there

1994runner

Did you put a new or rebuilt master cylinder on? I have seen MANY rebuilt masters that are junk out of the box

Adawg_08

brand new MC

rajin

here is how i bleed brakes and it works all the time.. 1) loosen bleed nipple, connect bleed hose & bottle to nipple. 2) have someone to depress brakepedel & keep holding. 3) now sqeeze calipers pistons in (make sure nipple is loosen, & clear) 4) brake pedel still depress, now tighten nipple. tip..try using clear bleeding hose so u can actually see what is comming out of the calipers.
hope this helps ....raj

Adawg_08

I'm sure there is no air in the lines though,
what did you mean by pulling booster line?

rajin

what i am saying that air might have been trapped in the calipers ..
one other thing, check plunger free play ie between master cylinder & booster (excessive free play will cause the brake pedel be low )
raj.

ovrrdrive

I've never had to manually adjust my reear brakes... They are auto adjusting.

By the way, if you have a new master cylinder and still have this problem it just about has to be either air in the lines or in the mc itself. Or possibly a ballooned rubber brake line or something weird like that.

chopitrakeit

Bleed the proportioning valve at the back too.

1994runner

Check to make sure the brake pads aren't sticking in the calipers. I have seen the slides on the sliding type of caliper get stuck and cause this condition. Basically the first pump pushes the pad to the rotor and second will give some brake feel. Make sure the pistons in the calipers goes back in the caliper easily as well and the pistons arent siezed... just a thought

Adawg_08

I took the new MC back to get a new one,
then ajdust the rear drums till' they scrub and calipers in the front,
then I guess bleed some more. get back to you in a couple days.
Thanks everybody.