Had those cad calipers on a car at work same problem. The bleader screws were not at the top because the caliper brackets placed the caliper in the wrong location. Had to ratchet the park brake and also remove the calipers and rotors then balance the whole mess to bleed. Reinstall and we had better brakes. Pedal ratio can be a problem as well as pedal travel. Can you get full stroke on the master? Some speedway stuff is not so good or well engineered. Plug rear line and see if you have brakes. Hope this helps (PM me if you need more help) Jim (55willys)
Thanks Jim! I know these calipers are a bitch to bleed. The pedal assembly is TCI and I've used a load of these with no problems on pedal travel. If it was only the rear brakes I'd have some concern about the calipers but the fronts won't lock either so I've pretty much isolated the problem to the MC or something around it. I've used these front brakes dozens of times with great success and in this installation they act just like the rears. We did swap out the original MC for the Trans Am unit and when we did so we had to put an aluminum plate between the MC and the booster. I set the adjustment where I felt it should be but I'm also thinking maybe the booster may have problems so I'm going to pull the booster and just run the brakes manually and see if that helps. I've put 4 wheel power discs on other cars and it was almost too much and you didn't want to nail the pedal or all four wheels locked instantly. I'll post up when I get this done.
The Cadillac rear calipers adjust by the use of the parking brake. Sooooo many Cadillacs I have worked on have had rear pads worn very little due to this. It IS mentioned in the owner's manual, but Caddy owners don't need to read, you see. You MUST hook up the parking brake and use it for these calipers to adjust. They will NOT adjust otherwise. This could be your entire problem. Cosmo
Cosmo, I have the parking brakes hooked up and I think adjusted properly. Can you elaborate on your procedure of bringing the brake pads in?
Koz...trollst is correct about those "low-drag" calipers. My understanding is they are exactly the same externally with an O ring and piston difference that gives the increased retraction. Modern rebuilders can easily mispackage all the bits and pieces (and have with those calipers!) so you might have them without even realizing it! Fitzee was having the exact same brake issue with a Stude he was building. I suggested this might be the problem and he changed over to a factory GM master cylinder designed for the low-drag calipers (had it available) and the problem completely disappeared. In your case you could do that if you have room, or you can change out the calipers for the old style. Check to be sure its the actual problem first of course, by C clamping the caliper pistons in the fully retracted position, off the rotor and without pads. ALL the way in, so the O ring flex is completely eliminated.
Actually the only difference is the beveled angle of the groove that the seal sits in. The leading edge of the groove on "normal-drag'' calipers is 15 degrees, and it's 30 degrees on ''low-drag'' calipers. The 30 degrees allows the seal to extend further when the piston moves outward, and thusly the piston retracts further inward when pressure is released. The cheapest and best NEW 'normal drag' GM metric calipers can be found here; http://www.southwestspeed.com/?sec=...ub=!!!GM+Metric&sssub=Steel Modified Calipers All others that I've found are remans for almost twice the money.
Simple. As per Cadillac - pump the parking brake until you have a hard parking brake pedal. And it stops the car. These WILL lock up the rears when working properly. Cosmo
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