I have a problem with the front brakes on my 87 C4- they hang up and do not completely release causing the front wheels and rotors to get very hot and excessive pad wear. I have pretty much replaced everything-rotors,pads,master cyl-drained ,flushed and replaced brake fluid. When I reduce hydraulic pressure by cracking bleeder valve or connection at master cyl or abs module they will release. I decided that the abs module is the problem-solenoid stuck so I bought a used one from another 87 on Ebay. Even though they look the same and have the same model # there seems to be an extra wiring harness on mine that the replacement does not have. Does any one have any info on this? Can I install the replacement as is? I would appreciate any help.

I had same problem and only solved it by rebuilding the calipers; pistons were cocking sideways in the bores, locking up.
Some have had problems with the hoses collapsing so they act as a one way valve not allowing the fluid to return when pedal is released.

Can't help on the ABS connections.
What wires/ plugs do you have and I can look up '87 service manual

I have replaced the hoses-we have decided that the problem is the abs module -if we crack the connection at the module the brakes will release- so there is probably a solenoid problem- the module in my car has 3 wiring harnesses - the replacement I got has 2- I called a local Chevy dealer- they confirmed that there were 2 different modules for that year but could not give me any more info-I have not found anything in my manuals to help.

Out of mt territory! TTT:cheers:

I have replaced the hoses-we have decided that the problem is the abs module -if we crack the connection at the module the brakes will release- so there is probably a solenoid problem- the module in my car has 3 wiring harnesses - the replacement I got has 2- I called a local Chevy dealer- they confirmed that there were 2 different modules for that year but could not give me any more info-I have not found anything in my manuals to help.

How much are the modules?

This actually happened with a friends C6 when he was putting on a big brake kit and didn't put the right shims on to center the caliper. But I suppose thats a little different then what you're experiencing.