Rear Disc rubs backing plate '98 OBW

[hankosolder2]

Greetings, gang!

 

I was doing a rear brake job on the '98 OBW and after installing the rotor on the driver's side, there was significant drag once the wheel was bolted up. I pulled the pads (no dice) and then backed the parking brake shoes way off (no dice.) I then noticed that there were evidence marks of rubbing on one area of the brake backing plate (about 1/2" long at the bottom.) There was a corresponding shiny ring around the lip of the old rotor/drum.

 

The backing plate is pretty beefy, so I didn't think I could bend it away. I lightly ground the contact area back which helped considerably. There's still a trace of rubbing around corners, but I'm sure that will fix itself in time.

 

The things I suspect are that a.) the backing plate was bent in some previous misadventure or b.) the wheel bearing is somehow sloppy or collapsing. c.) the hub is somehow out of tolerance. I think I can rule out the new disc being the cause as there was some rubbing with the old disc too (as proven by the marks.)

 

There doesn't seem to be any unusual play in the wheel bearing, and if it was loose I would expect it to rub at the top, so I'm guessing it's just a slightly tweaked backing plate. Has anyone seen this issue and am I on the right track?

 

Nathan

[EVOthis]

sometimes the ring/lip around the center of the rear rotors were the e-brake shoes go in rubs on the backing plate there....we see it alot when we resurface rotors....you can usually only hear it at slow speeds while turning.....nonetheless if you have a die grinder you can try and grind some of the lip off of the new rotor and see if it helps.....sometimes some road grime/ rust or whatever gets behind the backing plate and pushes out....

[yohy]

hankosolder2, you won't believe this but I just finished up a rear brake job on my '97 Legacy and had the exact same problem. Same side, same place. When I took it out for a test run, the noise sounded just like a wheel bearing ready to let go. I freaked out as there was no indication of a problem before I did the job. So back into the garage, take the brake pads off, look around, make certain they weren't binding, reassemble and road test. Same dang noise. This time I take everything apart, including the rotor. That is when I noticed the wear on the backing plate. I even switched the rotors to make certain one wasn't warped, nope both new rotors did it. Anyhow, I wire brushed everything down, cleaned it up, reassembled and this time NO noise. So what caused the rubbing...no clue. What did I do to eliminate it, I guess a good cleaning with a wire brush. But again, I can't tell you what cause they original clearance issue.

[hankosolder2]

I'm glad to know it's common and not something freaky with my car.

I'll probably take a bit more metal off if it doesn't fix itself.

 

 

Nathan

[Rooster2]

I have a Leggie 98 OBW that has made a very slight grinding noise since last winter. I couldn't find anything wrong with the brake assembly, so thought it was a bad wheel bearing. I took to a shop, but the mechanic said the wheel bearing was good. So, I just lived with the slight noise. Now, thanks to your post, I bet the noise is from the disc rubing the backing plate. I am relieved to know it is nothing serious or expensive to fix.

[yohy]

hankosolder2, really not certain of how common, but again, like you, glad it wasn't isolated to just me! Now I have done numerous rear brakes on Subaru's and have never run across this issue and still for the life of me, can't figure out why it happened. And then, why just the drivers side?

 

Rooster2, curious when you do your rear brakes, if you can update us with your findings. Oh, is the noise coming from the drivers side?