i did a rear discs conversion and also swapped out the front to DA brake. my brake was locking up then i changed to a 4040 proportion valve and it stop locking up for a little bit. maybe 2 weeks later locking up again... i bought DA booster and master cylinder, before i install them...1. i want to see if anyone had this problem 2. and if you guys know this will solve the problem. (this is on a 91 hatchback si)

 

I had the same problem with my EG6. I converted the rear and front with GSR brakes. My car locked up. It would work fine when its not hot. But after it's hot it locks up. I couldn't figure it out. I than, check the calipers to see if they were seized. They were fine. Next, I check the proportion vavle (RS 40/40) that was fine also. I than, check the master cylinder (RS 15/16). I loosen the lines connected to the master and only one line would have fluid coming out. I figure that the master was bad, I replaced it with a new one from autozone. Still had that problem (but now fluid was coming out both lines). I than check the brake booster (GSR 270V). The rod in the booster was to loose, so I replaced that also (one from a junk yard in excellent condition). Now it work's fine but at times it still locks up (you can feel it locking up). But when it lock's up I push the brake pedal all the way down and it releases the brakes. I been doing that for almost 3 months now and still can't figure it out. Hope this help you some what.

 

You both have a bad brake booster

 

i think its more like...the more you use the brake the harder it locks so another word it wont lock up if the brake was never pressed. (thats my case) also it slowly releases while the car is parked for awhile ...it seen like the fluid is returning very slow. anyhow do you guys think if i switch to DA booster and master, it will solve the problem?

 

oh, well do you think its also bc the booster isnt from a DA?

 

Cliffs:

don't fukc with your brakes, just upgrade the disks and pads, leave your drums alone, they are lighter than disk brakes anyway.

 

um...too late and i disagree with that... safety first...i dont care even if the drums are 100 pounds lighter.

 

any other tips?

 

Are you kidding me? "Safety first"???? and you go swappin around system parts?

Please, oh master of knowledge, share more of your thoughts.

 

Because its safer to have a system that only locks the rears

 

the stock braking isnt enough for a hatch with swaps but anyhow thanks sired91 and sp33 the rear doesnt lock, thank you very much.

 

All you really need is the DA rear assembly and a 40/40 valve no need to change the booster