I am having a problem with my brakes I have never encountered in my 50+ years of working on cars. I recently installed a C-5 front brake kit on my 1990 C-4 along with new calipers, pads, and new SS brake hoses all the way around. I bled the brakes afterward and had about 1 inch of pedal travel before the pedal became firm. Then when I started the engine the pedal went to the floor but I could get some pedal with repeated pumping. I again bled the brakes running a full quart of DOT 3 through the system. No air at all but the same problem. I have since tried three new master cylinders thoroughly bench bleeding each one first. Same problem. I just finished installing a new aftermarket steel booster from Zip Products, bled the system again, same result. The car is sitting on jack stands currently so I put the car in gear and with the booster line unhooked and plugged the rear brakes will stop the wheels from turning but it takes a lot of pedal pressure to do so. Could there be something going on with my ABS causing this problem? No lights are showing up on the screen showing a trouble code. I live in a small town and no one including the Chevy dealer has a clue nor does any one have the proper adapters to pressure bleed the system. Please help I am at my wits end and going broke replacing parts. Any help would be greatly appreciated!

 

What method did you use to bleed?

 

ABS is kinda tricky since there is a tool to pulse the ABS. The rest of it doesn't need to be pressure bled but if you must, THIS is what I have. Even without it, you should be able to gravity bleed the system and do a 2 man job to get the last out. You might as well forget GM since the have obsoleted the car eons ago. You could try taking it on the street and forcing the ABS to cycle by hitting the brakes HARD on a lonely street.

 

I think I used ¨ 3 quarts after restoring all calipers. Vacuum bleeding didn't feel as effective as pumping the pedal. Next time I'll buy the pressure bleed tools.

 

I have found that having someone in the car pumping the pedal while car is running works the best. Doing this with a hand vacuum bleeder takes forever especially when swapping out new calipers.

 

What c5 adapters did you use and are you sure they are oriented properly ? Could you possibly have the wrong or defective adapters? Also, the hardware provided with the C5 adapters are different lengths and must be installed in the correct hole(s).

 

I have Russell speed bleeders on the car and bled with those initially. I also had a friend pump the brakes while I opened the bleeders manually. I also tried bleeding the brakes with the engine running.

 

that is going to be my next step

 

Everything is installed correctly. I even sent pictures to the manufacturer of the adapters to make sure.

 

I guess it is possible during the initial bleed that you got some crap in your ABS pump. Mine was faulty and was locking one front wheel. I had the ABS pump replaced and now they tell me they can't bleed the rears. Had to order a master cylinder and just waiting to hear back.