I’ve got a 1994 Z28 (disc brakes all around) with a peculiar issue. First I had to replace the ABS pump because I wasn’t getting any fluid whatsoever to the rear and it was flashing a code, now no codes and fluid does get to the back of the car after I had gravity bled it for 30 minutes but when I’m bleeding it fluid only comes out when I pump the brakes and never when I hold them, even after pumping. The pedal is soft and I’ve bled the abs pump several times and the brake fluid resovoir is full but I just can’t seem to figure out the issue. Any help with this problem would be greatly appreciated, thanks in advance.

 

After installing the ABS pump, were you able to “home” the motors? If not, might be necessary. Or, use the procedure in the factory service manual (FSM) to bleed without homing the motors.

Free 1994 FSM download:

https://www.mediafire.com/?40mfgeoe4ctti

 

Yeah I was able to home them with a scan tool I’ve got. The issue still persists but I haven’t tried bleeding them with homing the motors, I’ll give that a try.

 

Have you considered a faulty master cylinder?

 

I hadn’t considered that, what way would be good to test for that?

 

Might show up as unequal front to back circuit pressure. That should trip the switch in the combination valve and turn on the red “BRAKE” light. But if that happens there should be a code in the EBCM, but you indicate there are no codes.

See if there are any diagnostics in the factory service manual.

The manual is the best reference. There's nobody left on this site any more. I spend most of my time chasing away spammers.

 

Alright I’ll look into the manual and hopefully figure this out, thanks a lot for your help!