Driv200mph

My brakes have always felt terrible in my car since I bought it earlier this year. The rotors were cryogenically treated before I got it. I have assumed the process didn't work at all and the current Pagid brake pads just didn't react well to the rotors.

However, today, I lost all power to my brake. It feels like something is behind my brake pedal and I can't push it all the way down???? It did this when it got hot last time at the track?

CAN ANYONE GIVE ME SOME ADVICE ON WHY MY BRAKE PEDAL IS NOT WORKING OR GOING ALL THE WAY DOWN.....PREVENTING ME FROM STOPPING WITH ANY NORMAL STOPPING FORCE? THANKS.

ps. After motor rebuild, I have a rattle somewhere in the motor that sounds like a heat shield vibrating, but we can't find the source? It originates under the intake manifold, but we can't find where????? At idle, it vibrates until you apply the gas and then it goes away. It sound like a loose piece of metal vibrating on another piece? Really embarrassing at stop lights. Thanks.

Epic2112

Well, when you get the chance you may as well take off the intake manifold and have a look. There's a lot of stuff under there that can rattle. last time mine was off I noticed that the rubber mounts for the ICV were so brittle that they basically crumbled when I touched them, so that's one possibility.

About the brakes, have you checked the hose that goes from the intake manifold to the brake booster (and on an 86 it probably has that little venturi thing in it)?

DDP

Its the venturi tube that is causing your brake problems. Get the kit from My Swiss...venturi delete. That might also be what is vibrating under your manifold. Good luck.

Driv200mph

Thanks guys! I checked with my mechanic, and he updated my brake line to '88 specs. So it's not the venturi tube. But, I don't have the rubber mounts under the intake anymore, so maybe that's it. Great advice. Please, any and all other ideas will be taken seriously as my first race is in two weeks. Thanks so much forum members!!!!!

MHT

there is a check valve at the brake booster, make sure that it is working. You should be able to blow through it in one direction but not in the other. If it has gone bad it will allow pressure to the booster and you will have no assist, or even worse, the booster will be resisting your effort to apply the brakes.

Jaak Lepson

Have you checked the master cylinder? It may be blown. I had mine replaced with a 1987 model ... went from a 17 mm bore to a 23 mm bore.

I had almost the same feeling on the track when mine went. It seemed I was pressing down on the pedal and it did not want to stop fast as usual.

Jaak Lepson YMMV