FailureOptional

Hello everyone. I'll get right to the point. My '88 RX7 GXL has some weird brake pressure. It started off with me replacing my rear passenger side brake caliper with an OEM one that I get off I guy that ran some street-x in his 7. Everything was fine and dandy, bled the brakes took it on a road test and all was running well. The next day I went out on a drive up the highway to the next town over to pay some bills, never shut the car off for anything. On the way back I started losing brake pressure gradually until I was about a mile away from home and lost all pressure what-so-ever. Got the car home, re-bled the brakes 3 times seeing if I somehow missed some air. Now It's just being really spongy. I replaced the original caliper to see if that was the problem but the issue remains. It seems like it tries to build pressure but then loses it again. I've talked to a few people about it and some say that it's a master cylinder problem and some say that I need to re-adjust my brakes. I figure it would be the master cylinder but I thought I'd ask you guys before I sink money into something that might not be the cause.

'88 Mazda RX7 GXL
178xxx miles.

Thank you.

gerald m

I have never heard of adjusting disc brakes if there is no visible leaks in your full braking system then you need to do your master . If there is no air anywhere in the system remove the master cylinder cover and very very slowly push brake down and observe the master if it is buy passing you should be able to see fluid washing through the master cylinder reservoir . In a good system there should be little or no fluid movement. Just make sure the brake is pushed slowly or you will have a brake fluid flood. can be hard on paint and eyes.