Hal Fisher

So I did not know of the easy way to remove the rusted on rear rotors on my '97 Z28 till it was too late. I smacked on the rotors with a hammer to get them off and now my ABS turns off occasionally and other odd braking issues (traction control initiates sometimes too). Anyone know what I broke in the rear end or what could be causing this after the rotor swap? Maybe something in the rearend?

Injuneer

Do you have ABS only (sensor on diff), or ABS+ASR (sensor on end of each axle/backing plate)?

Hal Fisher

ABS and ASR so the sensors are there. I thought about them and cleaned them off and nothing changed. Do you think something in the diff would cause it?

Injuneer

Is there a lot of "in/out" play of the axle in the housing when you pull and push on it? If the space between the sensor on the backing plate and the reluctor wheel on the axle gets too large, it might cause a complete loss of signal, triggering "ABS INOP", or might cause a low input at very low speeds, resulting in the ABS kicking ("LOW TRAC") in just as the car nears a stop, pedal drops unexpectedly, and the car rolls about 10-ft more than you were expecting it to before it stops.

Are you experiencing anything like that?

Hal Fisher

Yes, all those indications occur (low trac, abs non-op). While the axle doesn't move all that much it must be the culprit. So what can be done?

Injuneer

You could have the EBTCM read for codes to determine which sensor (or other component) is causing the "ABS INOP" light to come on. Short of that, the fact the problem popped up after hammering the rotors, you need to inspect the sensors. They are replaceable, but I think I recall a post recently where someone tried to buy a new one, and couldn't find them.

Look for signs of wiring damage, loose connectors, movement of the sensor or reluctor ring, etc.... My experience with a problem like this traced to an out of adjustment sensor on my Strange 12-bolt housing, so that's no help to you at all.

Hal Fisher

I suspected those and cleaned them off but now I'll replace them with junkyard donors.