could anyone tell me if im suppose to be able to stop the rear wheels from spinning when i jack up the car an put it in gear? they slow way down but do not stop, e brake is ajusted properly but does not lock em up, however slows them more than the pedal. pedal feel is good an firm, new mc,pads and steel brake lines, system has been bled many times but rears seam to have less presure when bleeding, putting test light on electrical connector on cv does not light, which indicates valve is good??, i know no other way to test cv, calipers seem good and moves freely. rotors are the larger ones 11.5" i think, all calipers have single piston if that makes anydiff. any help is appreciated thanks

Welcome to TGO. Other members have experienced this problem, so a search would probably locate the info you require.

JamesC

I have a 1990 Z28 with 4 wheel disc brakes, and I have the same problem. when the car is on the rack and in gear I can't stop the rear wheels from spinning. I have drivin it on wet pavment and stepped on the brakes hard, the front wheels lock up and the rear keep rolling with the car. so far I have replaced the master cylinder proportioning valve all 4 calipers brake lines, hoses and rotors & pads all are brand new from a chevy dealer and still no rear brakes. If you have had any luck in fixing this problem I would greatly appreciate you sharing what your solution was. Thanks

Do a search on "Free Travel."

JamesC

You need to disable the proportioning side of the cv, unscrew the front nut an remove sping and piston then weld the hole, it'll be like stopping a different car, the valve is a factory fup. sorry so late..