I've got an odd rear brake issue on an 01 Dakota with the 9 inch brakes. As I come up to a stop light, I put on the brakes, and they immediately go to the floor, followed by a loud bang / clunk from the rear. ABS light comes on, as well as the brake failure light. I get turned around, and since I live in the sticks, drive the mile back home. About the 2nd time I hit the brakes, the pedal comes back, but there is a grinding from the rear brakes, and both the ABS and Brake Failure light go out. Ok, so I park the truck, and the next morning run my ABS scanner, no new or stored codes show up. I pull the wheels, and both sets of shoes look fine, and there aren't any grooves or other wear marks on the drum. With the wheels and drums off, no grinding when I turn the axle by hand, or when I start and put in reverse. I put the drums back on, and when I hit the brakes, the grinding is back. Still no codes or lights, and the fluid looks fine front and rear. Ideas?

 

For kicks and grins, does it grind with the tires and drums still on, with the truck in gear on jackstands?

 

I ran it on stands with the drums off, all of the brake hardware still intact, no noise. Put the drums on, and eased on the brakes, and it grinds.

 

check clearance from drums to backing plates, and the edge of the shoe to the face of the drum. Check inside of drum for marks. Definitely sounds like the shoes have moved on the support springs

 

Thanks, I hadn't really even considered the springs, I just "knew" it was going to be a broken shoe or other component failure. The drums look fine, normal wear but no gouges, cracks, or grooves. Any thought on the pedal to the floor, ABS lights etc? Usually broke means you have to fix something, not nevermind, just kidding. I'll pull the wheels tomorrow and check the clearances.

 

yea, i mean it definitely sounds like the shoes may still "be there", but not be where they are supposed to me. Either they moved out and are rubbing the inside face of the drum, and/or they came off the wheel cylinder (you'd notice this), causing it to over extend, and the brake pressure sensor would detect that. But usually that would cause much worse problems.

Only time the ABS and "brake" lights SHOULD come on in normal driving is if the center sensor on the axle loses a signal to the tone ring on the ring gear, or the ring gear comes to a complete and sudden stop.

Something else that I didn't consider: you might have a busted wheel bearing. The axle doesn't weigh much, but slap the drum and tire on and boom, you have a load.

Try putting only the drum on, and hand-tighen it down with a pair of lug nuts. See if it makes noise then.

 

Well it looks like it is the wheel bearings. I believe that could also explain the ABS and brake light issue as you detailed it. If the bearing broke, it may have locked it up for a quick sec. Just a guess, but I don't like things that just go away....they always seem to come back at the worse times. Thanks for your help.