Just bot a very nice '86 Sport. Engine only has 30K on it and everything seems very tight. Except the brakes. I have had the pads replaced, and the system bled TWICE. The brakes are still spongy. The old owner said he replaced the master cylinder (it is new). I checked and found that there are two master cylinders listed for the 86. One is for the "hard" suspension and the other is for the base model. Since the Sport (which I have) has the hard suspension, I suspect he put in the wrong master cylinder and it probably does not have the volume throw necessary for the bigger calipers in the hard suspension package.

Is there any way to tell if the mastercylinder is the wrong one?

If it is the right one, is there any way to fix the spongy nature of the brakes. I understand the the 2nd gen brakes were naturally spongy.

Thanks

ab

 

Not sure about the master cylinder, but a set of stainless steel brake lines should help. As the brake lines get old, the rubber tends to expand when the brakes are applied.

 

Well, you said it was bled 2 times, so there should not be any air in the system....that would be the first suspect.

I am not sure what you heard from where though, but I can say that the stock brakes on my 88 vert (4-piston front, 1-piston rear) have a VERY firm and responsive feel. They are not spungy at all, so I would keep looking into your problem (I mean don't accept it as a foible of the car).

One thing you could check is all the check (one way) valves for the brake booster....if these are not functioning correctly, then I suppose it could make them spungy.

Just some ideas, I am not an expert.....keep checking though, I have had total brake failure in my RX-7 before (due to a failed check-valve), and it is NOT a plesant experience.... Luckily I had PLENTY of room ahead.