Brakes locking up after a few min of driving.

[caseyfoster]

Ok this has been going on for a while. When i pull the car out of my driveway the brakes are completely fine. After a few min of driving i can feel the brakes dragging a little bit then a few more minutes go by and it gets worse and worse until i can barley move the car when flooring it. Ive replaced the master cylinder , fluid, and all the brake stuff is brand new. z32 calipers, steal braided brake lines, 30 mm rotors, and new pads. I found a thread online of people adjusting the booster arm (has a little nut on the end that you can unscrew or screw in to make the arm longer or shorter.) I made the arm as short as it goes just a few min ago and took it for a drive, it did the same thing as before just took a little bit longer. Can it be that my brake pads are just too new and have not been warn down at all and is causing this? WHAT CAN IT BE HALPPPPPP

[Neejay]

Try this:

Hold down the brake pedal -> turn off car: If the pedal gets stiff or pushes back at your foot, you have a brake booster vacuum leak.

[caseyfoster]

Try this:

Hold down the brake pedal -> turn off car: If the pedal gets stiff or pushes back at your foot, you have a brake booster vacuum leak.
Just tried that it did not push my foot back.

[JJ Alfano]

brake booster

[caseyfoster]

brake booster where?

[Casey]

honestly. go for a drive get them to lockup. pull back into your house. jack car up. see if your rears are locked up. becasue it might be your calipers... but im guessing its both front and rear brakes.

as far as adjusting the brake booster. im not sure how at all. tis why i was like... uhhhh when you called earlier.

oh and his brakes look to be installed perfectly. i saw his car.

i really cant think of why this is goin on.

it almost sounds like theres a 1 way valve in the brakes somewhere making fluid only go into calipers and not out of them. but im pretty sure that cant happen lol

[Neejay]

Just tried that it did not push my foot back.
Did it get stiff/firm?

[caseyfoster]

Did it get stiff/firm?
Its acting the way it should.

[flip]

You got correct brake pads and correct rotors?

[hellfire]

You said it does it after a few minutes of driving. Does it correlate to the amount of times you push the brakes? Like, if you sit still and just pump the brakes will the lock up eventually?

Tyler

[caseyfoster]

You said it does it after a few minutes of driving. Does it correlate to the amount of times you push the brakes? Like, if you sit still and just pump the brakes will the lock up eventually?

Tyler
No it happens when i drive for a while the brake pads heat up and expand and eventually grab the rotor to a point where the car will not even roll down a hill.

[JJ Alfano]

my friends did that, we swapped the brake booster and all was well again, i dont know if it was an easier fix than that, but 30 minutes and we were good as new.

[michaelespiau]

listen I had this problem right after I did the 5 speed swap.... listen carefully it is either the master cylinder which you just replaced or the expensive brake booster... it sucks to replace so good luck it was a two person job... I know what you are going through lol it sucks because the more you drive the worse it gets and the only way to fix it is to pull over and wait... but I am 100% sure that it is either the brake booster or the master cylinder...

and that is what jj was talking about

[Casey]

okay youve got an s13

brakeboosters are on 90 percent of parts cars. lol...

just go get one. :)

call tyler. he is a trip down 400 to 85 from you.

[hellfire]

^^ Yup.

I can bet you the problem is the BB. Only thing that would make the car act that way.

Tyler

[Casey]

he is currently swapping calipers from left side to right side. he got them swapped had bleed screw on bottom. hes gonna switch em and then see what happens. :)

[hellfire]

That shouldn't fix anything. If he had pedal pressure like that then its fine. The only thing the bleeder on the bottom would do is not allow the caliper to bleed properly because a pocket of air would remain in the top section as all the fluid just poured out the bottom.

Tyler

[caseyfoster]

tyler how much for a brake booster? im pretty sure one of your junk cars has one

[hellfire]

Pm'ed.

Tyler

[Casey]

That shouldn't fix anything. If he had pedal pressure like that then its fine. The only thing the bleeder on the bottom would do is not allow the caliper to bleed properly because a pocket of air would remain in the top section as all the fluid just poured out the bottom.

Tyler

ya but its def worth a shot to swap it. sounds like he still needs a BB :)

[michaelespiau]

yep

basically fluid get hot expands but brake booster won't allow fluid to flex or come back... it acts like a one way valve

[Nisxsz]

my brake booster leaked for a while, a vacuum leak. i unbolted the mc and wire brushed and sanded the surface. then applied rtv on the surface and the edges. however, my problem did not affect my braking. when i shut the engine off, id hear sssssss.... im like huh..? lol. so.

[s13gtr]

sounds like a brake booster or a vacuum leak. check the vacuum hose going to your booster and see if it is cracked. if so replace the hose or put duct tape for a temp fix. if the hose is fine its gonna be the booster. if you have a z32/skyline brake upgrade only a small amount of ppl need a new booster due to the size of the master cylinder they are using (nissan has a several master cylinders in different sizes and im not sure which comination of master cylinder/ booster goes for what). i have a s13 with 30mm aluminum front and rear setup with a 15/16 master cylinder with a stock booster and i never had no problem.