'96 850 front brake scraping sound...I think?

sunnus · Post by **sunnus** » 28 Oct 2009, 00:29

Just changed rear rotors and pads on all four wheels. Thankfully it seems to have resolved the shuddering vibrations that it had when braking before.
It did not however change the light scraping sound coming from the driver side wheel. It sounds and feels as if the pads are always lightly rubbing, when the brakes are not applied. It's like the brakes are not releasing completely. Strangely, the sound is the same with the new pads as with the old ones. I thought the old pads were causing it. What could it be?
During the jobs I did come to find that my axle on that side also needs replacing. The boot looks fairly done. I guess that's my next task.
Could the worn axle be causing the rotors to rub on the pads?
For a moment I though wheel bearing, but most of the sounds I've heard described were a low vibration, not a "light scraping sound"
ANY helpful suggestions would be greatly appreciated. Thnx!

Post by **polskamafia mjl** » 28 Oct 2009, 01:39

Welcome to MVS. It's probably one of two things. A. your caliper is hanging up. This is fairly common and I think it has happened to me as well. To fix it, regrease the guide pins as well as the piston in the caliper itself. In addition, if your brake lines are really old then that can also cause the caliper to stick. B, and I doubt this is it, is that one of the bolts that hold the caliper to the caliper carrier are missing or loose. This happened on my friend's pick up when he forgot to replace one of those bolts.

Sticking Caliper -> https://www.matthewsvolvosite.com/forums ... php?t=9915

anmartin44 · Post by **anmartin44** » 28 Oct 2009, 13:54

I had a similar sound awhile ago and it driving me nuts. I thought I had a warped rotor or something so I took my wheel off to look around and found a dime-sized pebble lodged between the back of the rotor and the metal plate guard. I wedged it out and problem solved. So check everything before you go tearing stuff apart, it could be something stupid.

sunnus · Post by **sunnus** » 28 Oct 2009, 14:31

Thanks so much for the replies. I had thought pebble as well, because that happened to me on my old car, and it sounded just like this. Un fortunately i have searched throughout, and there does not seem to be anything in or around there that could be scraping.
I'm going to grease up the pins and piston today and hope for the best.

Post by **Ozark Lee** » 28 Oct 2009, 20:07

Another thing to check is the shield behind the rotor. When the ball joints and/or control arms are replaced it is common for the pickle fork tool that separates the ball joint from the steering knuckle to punch a hole in the shield and it can drag on the rotor and result in the same noise. I did it on a couple of mine and I was able to clear it with a big screwdriver by pushing the shrapnel back away from the rotor.

...Lee

voodoorobaz · Post by **voodoorobaz** » 28 Oct 2009, 20:14

Had same problem, turns out the dust shield needed to be pushed back a bit and problem solved

sunnus · Post by **sunnus** » 28 Oct 2009, 20:37

THanks again!
I have now determined that "the sound" is actually in the ds rear rotor (which was just replaced. It seems that the parking brake shoes are what is not releasing all the way. THe pads look good, and I've adjusted them all the way in, but the light scraping persists. With the wheel and rotor off the whole parking brake shoe mechanism seems to be able move up and down and around very easily. Which ever position I put it in, the rotor still rubs a little.
I can't imagine changing the shoes would help. It seems like they would take up more space and rub more.
I also tried adjusting the parking brake handle by tightening the big torque bolt which was pretty loose, and although the handle seems to engage without going so high, the pads still don't back enough not to rub.
Any ideas?
Thanks in advance.

sunnus · Post by **sunnus** » 28 Oct 2009, 20:40

It also did seem like the dust shield rubbing a bit, but on inspection it is very solidly in place and can't be moved much.

Post by **Ozark Lee** » 28 Oct 2009, 21:18

I was able to get one of mine cleared by using a big screwdriver from the bottom and prying the damaged area back away from the rotor.

On the other one I just pulled the rotor back off and beat dust shield with a hammer until it cleared like normal.

...Lee

Post by **polskamafia mjl** » 29 Oct 2009, 01:39

From your post I couldn't tell if you had definatly identified the source of the scraping. This may help -> With the wheel off try spinning the entire assembly. Ideally, if nothing is scraping, etc, then the entire thing should spin freely. If it's scraping then you may be able to tell exactly where it is coming from.