weinman

Hi All, my 84 gsl is almost road ready, but the master cylinder and brake booster are shot. I have found master cylinders all over the place, but not boosters. I read that master/boosters from other cars/years will work, but don't know what to get. what will work? I am not looking to do any mods to the car, just bolt something in that will replace the oem parts. thanks in advance for the help.

Frogman

Your booster can be rebuilt . I had mine rebuilt locally . It was basically full of brake fluid .

rsv1rx7

What are your issues? Heavy brake pedal, leakage, no brakes? I have rebuilt my brakes, new calipers and new master and slave but I still need a lot of pressure on the pedal to stop. I'm thinking like you that the booster could be bad.

Toruki

I'm working off memory here, and not in a position to do much searching rn. I recall a thread in this forum where despite a master cylinder replacement and booster rebuild they still had poor breaking. The problem turned out to be that the pushrod from the brake pedal into the booster/ master was not inserted correctly...reversed iirc.

EDIT:

OK, found the post I was thinking of, but it was for a soft brake pedal: The booster has a "reaction" disk in it. If you had the whole assembly apart, maybe you have the same issue as this person.

https://www.rx7club.com/1st-generati.../#post12437745

The 2nd gen thread that helped the guy above, pictures etc.

https://www.rx7club.com/2nd-generati...r-fix-1103221/

weinman

Thanks to those who have replied to my question. I wish I could answer better, but I am having the car worked on by a mechanic and he says they are gone.

Frogman

I doubt both are blown. If your master is shot it would leak either internally or externally , leaks cause very mushy brakes at all times . external will drain your reservoir and you will be able to visual spot it . A Failed booster will cause hard brakes and or inconsistent brakes. If your master fails INTERNALLY through the rear seal you will get a booster coconut

midnight mechanic

Hard brake pedal indicative of a bad booster turned out to be a vacuum leak. Pump down test with a vacuum pump showed that I just need some vacuum line clamps.

Frogman

+1 he should start by replacing al of his booster hose and clamps . You only need about two feet of booster hose and six clamps . .

Make sure you don't throw out your check valve and to place it in the right direction

weinman

Thanks again everyone. I found an old thread that mentioned Prior Brakes in Mesquite TX. I contacted them and sent it out on a saturday. Had it back on Thursday.$140. Highly recommend them.

mazdaverx713b

iTrader: (91)

What work did you have them perform? Was the booster not holding vacuum?