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Dec. 6, 2011 6:46 a.m. Klayfish HalfDork

Posted this on the Volvo forum, but wanted to ask the braintrust here. Since I'm a novice at fixing cars, I obviously made a mistake somewhere and want to figure it out.

I need some help with my '96 850GLT wagon. I replaced the rear pads and rotors on Sunday. This was only the second time I had replaced pads/rotors, the first one was on the car in my avi. When I went to put the left side caliper back on with the new pads, I noticed it was a really tight fit. Obviously, it was too tight. The first mile or two was fine, but then suddenly there was a loud noise coming from the left rear of the car. Hard to describe, you'd have to hear it. I turned right around to head home. It was a definite rubbing sound, but not metal on metal. It was very loud. It was a constant pitch sound, like something dragging. It only seemed to happen above 25-30mph, it would quiet down quite a bit and go away at lower speed as I was heading home. When I got home, I could smell brake pad, and you could feel some heat coming from the left rear wheel. Rotors weren't glowing (it was dark outside) and it wasn't an incredible amount of heat, but noticable. Right side rotor seemed fine, a bit warm to the touch but that's it...no noises, nothing. Pulled the left rear wheel off and you could see the pads pushed up against the rotor. Pulled the caliper back off. I figured maybe I didn't get the caliper fully spread. I put the old pads back in (they still had some meat left...it was the right side that was worn out and caused me to replace everything). It was late at night and I needed to at least get it drivable for the next morning, so I figured I'd go back to what I had (except for the new rotor). The problem is 90% gone now, but I can still hear that noise faintly at higher speeds. When I got to work this morning, the left rear was slightly warm compared to the right.

Did I not get the caliper spread far enough, or did I damage it? What should I be looking for? I used a C clamp to spread the caliper. When I was spreading it, there was a few spots that had significant resistance. I'm confused...
Dec. 6, 2011 9:34 a.m. AngryCorvair SuperDork

if that caliper has parking brake function built in, or if it's one that you have to rotate the piston as you push it in, then it's possible that you hosed it by pushing the piston straight in with the c-clamp.
Dec. 6, 2011 9:53 a.m. bludroptop SuperDork

The e-brake on these is a standard drum arrangement with the rotor hat acting as the drum. The caliper pistons should push straight in with a c-clamp or similar.

Is it possible that you didn't get the rotor seated correctly on the hub, causing it to either wobble or be offset from the correct position? Or could it be a frozen caliper piston that won't retract once pressure is released?
Dec. 6, 2011 10:05 a.m. Ranger50 Dork

ride the ebrake around engaged. the shoes in the ebrake need to be seated to the rotor.
Dec. 6, 2011 10:14 a.m. DrBoost SuperDork

Are the pads aftermarket? I've had more than a few instances of the pads being thicker than OEM and had to remove some material from them.
Dec. 6, 2011 10:37 a.m. foxtrapper SuperDork

And did you dress the caliper where the pads sit in there? Particularly on the outboard side? Rust and crud tends to build up there, preventing the pad from going all the way back against the piston. If you don't address this, you'll likely create a mechanical bind of the pad against the rotor.

The bang is quite likely the pad bending until it finally popped.
Dec. 6, 2011 11:01 a.m. Klayfish HalfDork

Thanks guys. Yep, the e-brake is a drum set up, using the rotor hat. I bought the rotor and pads from Autozone, so they're aftermarket. They weren't the cheapest "Valuecraft" or whatever that is, it was the more expensive store brand they carry. I did see rust and crud on the inside of the caliper where the back of the pads sit. I cleaned it up, but perhaps I didn't get it enough.

What's the easiest way to check the caliper piston to see if it's not retracting properly? I can pull the rotor off and reseat it. Would the improper seating cause the heat and noises I heard? Seemed strange that it got quiet and disappeared below 25mph. I figured if it was really rubbing, I'd hear it at all speeds. When I was going at higher speed, hitting the brakes really didn't make the noise stop, only going slower did.
Dec. 6, 2011 11:05 a.m. DrBoost SuperDork

Did you remove the rotor? How did you tighten the wheels? I'm wondering if the rotor is warped (any "thumping" felt in the brake pedal?) or sitting on a rust build-up.
Look at the pads (the new ones you took off). How do they look? Are there any patterns you can tell us about, can you get pics of the caliper with and without pads, pics of the pads, pics of your neighbor (female) sun-bathing?
Dec. 6, 2011 11:26 a.m. Klayfish HalfDork

I changed the rotors with the pads. After the test drive, I pulled the caliper back off, but not the new rotor. I don't feel any thump or pulse in the pedal. When I took the new pads off, I didn't see anything unusual. I had only driven maybe 5 miles or less. I'll have to grab some pics later. The rotor didn't show any patterns on it.

As for the pics of my neighbors. Let's see...on one side there are two gentlemen in their mid-50s, who are more than just roomates. Off to our other side is a husband/wife, but they're older too. Or I could go across the street. It's a farm under renovation. The only thing living there is a cow, 3 horses, 2 chickens and several cats. What's your pleasure?