Brake Problem!!! Need Help Please!

[DrftS13]

Hi guys I really need your guys help. I am running 300zx brakes front and rear on my S13 coupe. with a Z31 master cylinder and a z32 Brake booster but for some reason the brakes wont hold pressure...like i bleed them and then the next time you step on the brakes they go to the floor!....it really sucks!

the crazy thing about it is that i had the same brake setup with a stock S13 booster and it worked just fine....

please help me ive checked all the lines and nothing leaks

[scott240sx]

did you gravity bleed or did you have someone pump the brakes

[DrftS13]

i have did both methods of bleeding...(gravity and pumping)

[scott240sx]

you could still air in the master cylinder or it could be bad. i had another car with the same problem. i would bleed them but it wouldn't help then i had to take it to my dads shop and he said the master cylinder needed replacing. after that i didn't have any problems

[DrftS13]

i have both a brand new master cylinder and brake booster!i might just pay a shop to fix it but i fear they will just be doing the same thing i am...troubleshooting the problem..but i will end up paying them hella money!....

bump: any help please

[TXCumtrensh]

Check to see if you have a leaking piston... its a possibility..

also, You should really try re-bleeding the Z31 MC (off the car)

[DrftS13]

leaking piston?...the MC piston? I have bench bled the MC twice already...this is sooo frustrating

[scott240sx]

who knows you could have bought a bad mc?! if you bought it from a parts store take it back and say its a faulty one. also when you go back to bleed the brakes you don't keep finding air in the lines do you?

[DrftS13]

no when i bleed the rear there is no air in the lines...but when you come to the front its a whole different story...imma jus bench bleed the MC again and hope for the best...240s

[scott240sx]

you might have an air leak in the front calipers!? is it the same on both sides? double check all of the fittings and bleeder screw.