New Rear Calipers Turns Light On - Third Generation F-Body Message Boards

DJ Delsym · 07-01-2009, 10:27 PM

My '87 Iroc was previously having squeaky rear breaks so I had replaced them but found out I had a seized caliper so I replaced those aswell. Everything bolted up fine, bled the brakes, and set her on all fours.

When I went to test her out I noticed my brake light is on with my e-brake disengaged. My e-brake never worked since I got her but I still use it anyway to keep it "adjusted" but now the light will not go away. I did however loosen up the parking break and and still light is on.

I've read about the free-travel screw but that is on a different style caliper and only see a Torx screw directly behind the brake line bolt. Is that it? If so, I don't think i would be able to adjust it underload being as I can't get a bit in there with the line still attached.

I've also read about the light coming on due to a pressure difference between front and rear systems. I bled the brakes properly so would this be stored in the computer like a code I have to clear?

Thanks for reading!

squirted1 · 07-01-2009, 11:02 PM

it could be your pressure differential switch that is mounted to the pro-valve. if the switch has been "tripped", the light will come on.this can happen if there is a pressure loss on one side of the valve. a chiltons or haynes manual should list steps to reset the switch

DJ Delsym · 07-02-2009, 03:46 PM

Well my Haynes manual told me how to check the pressure differential switch and it came up that the electrical circuit is bad. I don't think that is the case because it worked properly before hand and the bulb is not blown because when I pull up my parking brake the light shines again. (I kept the connector disconnected)

I grounded both the connector and switch to the strut tower and came up with the results above. Any other suggestions?

Also, putting the car in neutral and spinning the rear wheels by hand seem to be abnormally difficult or is it normally this tough?

UPDATE: I even tried a new combination valve out of a donor car sitting in my drive way. Light is still on. Now I am thoroughly confused.

DJ Delsym · 07-02-2009, 06:49 PM

New valve did the trick, when I brought the car out the light went off and stayed off. Without this forum's archieves I'd still be stuck in my garage. Kudos to TGO