Muddin03

I've got a '93 D350.
I just got through reading the previous thread about the brake warning light and abs warning light.
I checked the brake fluid...it was low (the side for the rear brakes). I filled it up. The brake warning light is still being tripped. With the fluid level being low, I would assume I have a leak somewhere. With it being the rear brakes that were low...I wonder if I have a wheel cylinder leaking. I've looked over the truck and I'm not seeing anything wet so far..but I haven't pulled the rear wheels off and the drums yet. I figure a leaky wheel cylinder might not allow the pressure in the brake system to be very high which might trip the brake light. Is it possible that a bad wheel cylinder might trip the abs light? Also, I've recently noticed the passenger side rear tires have been chirping when I apply the brakes, and I'm not putting much pressure on them. The pedal is still firm.

Now for a little history-the lights have been on since I've owned the truck. When I bought it the lights were not on. After I bought it, I got into some construction on the drive home. They routed everyone onto a bad street where they had laid some pipe or something underneath the street so it had a rough dip in it. Nobody saw it so everyone, including myself, hit it hard. Instantly after I hit that, both lights came on. Does that raise any eyebrows? Thanks ahead of time for any advice 8)

Lil Dog

First off... WELCOME !!!!! ;D

Well, if you have read the threads on the Brake/abs lites then I hope you have tried just pulling the plug on the module or the battery to reset the ABS computer. If you have and it still comes back, then from the bump you hit, maybe the plug to the pickup on the diff got jolted or dislodged.

With the chirping wheel, could be brake cylinder or axle seal. A slight seal leak either way makes for instant brakes.

If the ABS really ticks you off, I know alot of guys pull the plug on the module and forget it..

J-eh

2manydogs

The ABS light also senses low vacuum- does your pedal feel a little hard to push? Shut the truck off and push on the pedal, you should get a couple of pumps before it gets firm. You can put an ohm meter on the terminals of the sensor on top of the diff to see if you have a complete circuit. An open circuit will make the light come on. Also check the ABS valve on the left side of the truck's frame rail behind the wheel. It should be a complete circuit also. Loosen the nuts holding the Master cyl. to the booster and pull it back a little to check for brake fluid. Just some of the things to check. And, like me and others, UNPLUG it behind the glovebox > I don't like it any way! Jim

2manydogs

I could be wrong about the vacuum thing- I remember my BRAKE light coming on when my booster was pooping out but not sure about the ABS light. I've got to quit engaging fingers before putting the brain into gear! Jim. ???

Lil Dog

[quote author=2manydogs link=board=9;threadid=20090;start=0#msg188936 date=1064458150]
I could be wrong about the vacuum thing- I remember my BRAKE light coming on when my booster was pooping out but not sure about the ABS light. I've got to quit engaging fingers before putting the brain into gear! Jim. ???
[/quote]

Still good points to check anyway, I think you are right about the low vacuum. But the checks on the wiring is a good point.

J-eh