The "Brake" warning light on the dash of my '88 Dodge Raider has been on for a while and I am trying to figure out what the cause is. Brake fluid is fine and the parking brake is off. I can't find anything in the Haynes book that would tell me what can trigger the light. I think the rear brakes may need new drums (parking brake adjustment is about at max and the lever still comes most of the way up, but the pads were replaced about 5000 miles ago), but I would have thought that the vehicle was built before all the fancy brake wear sensors they have today.

If it's just a short in the wire somewhere that's fine and I can live with it, but I don't want to be ignoring something important.

I wanna hear the answer to this mine stays on too

either the float in the master is stuck or the brake switch for the parking brake is bad.

Welcome to the forum <img src="/forums/images/graemlins/kewl.gif" alt="" />

Pull the cap off the reservoir and make sure the rubber diaphragm on the underside of the cap is not sticking out. This is the most likely cause as the diaphragm pushes the float down. The long term fix is to flush your brake fluid.

As the fluid's water content increases over time it will expand and contract more. On a cool or cold morning it contracts enough to suck the diaphragm down...at least that's my theory. Once the diaphragm is sticking down it stays down. <img src="/forums/images/graemlins/cheers.gif" alt="" />

X2 on the diaphram! <img src="/forums/images/graemlins/kewl.gif" alt="" />

Eric W.

Both answer are right on. If your brake fluid is not clear than it need changing as it has junk in it. It's a simple task.

My vote is the float switch in the master cylinder.

I always wondered why the diaphragm in a master cylinder would expand like that. I thought it was just getting old and would fall because of gravity, but the reasons above make sense to me.

I'd buy a new cap and bleed/flush the brake lines. Good insurance.

John B.

I took the cap off this morning and it didn't look like it was sticking out, but once I put it back on, the light was almost completely out. So maybe that was the problem after all. It is amazing how little things like that cam be so problematic to track down. Thanks for all of your suggestions.

Also some of the early design caps tend to leak and the rubber gets out of place. If I remember right the white cap is the newer design and has better tabs to hold the diaphram in place.

Kevin