Off Roading Forums banner

Brake warning light on....CJ *UPDATE*

3K views 12 replies 7 participants last post by  lindy80cj7 
#1 ·
Well after trying to track down the rattling behind my dash it appears that the brake warning light bulb was out of its socket and bouncing around in the spedo cluster. Plugged it back in and the light is on. I unplugged the wires to the proportioning valve and the light went off. So I'm guessing I've got a problem. My brakes have always sucked. I usually have to pump them twice to get good pedal pressure. I also have to add brake fluid once a month or so when the master gets down to around half full and I lose a lot of pressure.

So my guess is I've got a leak somewhere or something is screwy with my proportioning valve (I think thats what its called). I'm going on a long trip this coming weekend to the Badlands and I'm sure it'll make it and stop ok now that I've added fluid but I don't like the situation I'm in. Especially with snow on its way I'd like to get my brakes working right.

So what am I looking at here? All the lines were supposedly replaced by the PO and I know NOTHING about brakes. I know the best way to learn is to do it yourself but I'm not real comfy with doing my own brakes quite yet. What advice can you give me?
 
#3 ·
Re: Brake warning light on....CJ

Yes, you've got a problem. That light comes on when there's a difference in pressure from the front to the rear. Usually when you work on the front or rear it'll set it off and a good bleeding all the way around turns it off.

Having to refill brake fluid once a month, lack of pressure and the light all tell me you've got a leak. Find the leak and you'll probably solve your problem. Brakes aren't that hard to fix. Get a manual and follow along.
I would suggest checking your brake line at each wheel for leaks. If not there, then start tracing the lines till you find the wet stuff.
Also, bear in mind that you should have the larger brakes front and rear. If you end up replacing parts, make sure you get the right ones. Most part stores just carry the smaller later model CJ brakes and will sell you the wrong parts. They're clueless.
Brakes aren't that hard. You just have to do it right. Get a buddy thats done them before or take a day and follow your manual. One of the easier fixes on your Jeep.
 
#5 ·
Re: Brake warning light on....CJ

Drury is right - anything else you do will be taking shots in the dark until you get the leak fixed. That shouldn't be hard - look for the wet spot


If the leak is at a tubing joint don't try to tighten it with an open end wrench; get a tubing wrench in the right size. Remind me and I'll be sure to bring mine along just in case.

After all leaks are stopped, you probably won't have any more problem unless the leak was in a slave cylinder and soaked the friction material. If that's the case you will also have to replace it too.
 
#6 ·
Re: Brake warning light on....CJ

Well today I waited until the manager of my apartment complex to leave (they have a fit if we wash our vehicles) and when she did I pulled off each tire and checked the brakes. Here's what I found....

1. Drivers side front disc was clean, no fluid to be found on any hoses, and turned freely.
2. Passenger side front disc was clean, no fluid found anywhere.......BUT ti was hard to turn. The outside pad seemed to be pressing hard on the disc and i could see a little bit of light between the disc and inside pad. I don't know what that means if anything.
3. Both rear drums looked clean and all hoses were good. However the wear pattern on the pads was kinda grooved. I don't know if thats from dirt getting in there or what. I don't know whats ok vs. bad so I don't know if thats acceptable for rear drums.

4. All hard lines seemed good.

5. There was definate wetness around the top of the prop. valve. It seemed to be accumulating around the switch on top where the brake warning light wires hook up. I wiped it down and I'm going to go back and look tommorow to see if its wet again. If it is I know where the problem is, but then I don't know how to fix it. Hopefully we can figure this out together.
 
#9 ·
Re: Brake warning light on....CJ

Sounds like more than one problem.

1)
The front brakes sound like you have a caliper (or 2) sticking. There will normaly be a slight drag on disk brakes, but it should not be "hard to turn". If the outside is tight, check your caliper slides. If you pry your caliper outboard a little, it should compress the piston. Then you should be able to move the caliper in and out on its slides.

2)
The leak sounds like you might have a bad master cylinder. Which would also turn your light on. Check behind the master cylinder where it mounts to the firewall (or booster if you have power brakes) see if it is wet or if the paint is soft and bubbled up. Brake fluid will soften the paint. So even if there in not obvious fluid there, it will effect the paint. Also if not power brakes, check inside where the pushrod goes throught the firewall. Look for leaks around the boot or streaks on the firewall where fluid has run down.

One other thing I just thought of on the light. The same light is the idiot light for the emergency brake. Check the switch to make sure it is plugged in and is getting a ground when the E-Brake is off. This is a spring plunger switch up on top of the e-brake assy behind the dash. If in doubt, disconnect the wire to the switch and ground it to see if the light goes out.

Good luck. I hope you find your problem(s) before it finds you.

Bill C
 
#11 ·
Re: Brake warning light on....CJ

In reply to:

Grounding the wire turns the light on. Leave it disconnected from the switch for a while and see what happens. Those switches are pretty cheesy affairs.

[/ QUOTE ]

OOPs, I think you are right. I had it backwards. Thanks for catching my gaff.

Bill C
 
#12 ·
Re: Brake warning light on....CJ

Sounds like you may have a bad warning switch. Not because the light is coming on but because you have to fill both sides of the master reservoir. The splitter/proportioning valve is the only place other than the master where the dual system comes together. The switches sometimes develop a leak and that is were you are seeing the wet spot.

I know you said you didn't find anything at the wheel, but check the back side of the tires for radial marks. Usually, a leaking slave will show there.
 
#13 ·
Re: Brake warning light on....CJ

Due to serious nature and the consequenses if not repaired properly, I would still recommend someone knowledgeable to assist him by looking over his shoulder. When it was mentioned that he had been adding fluid for some time, red flags went flying.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top