Brake rubbing noise after new pads

alvocado · October 11, 2005

I replaced the rear pads on my 2002 Yukon Denali this evening after hearing a rubbing noise coming from the driver's side rear wheel. The truck has 55k miles and I was still on the original pads on all four corners. When I removed the inboard pad, I discovered it was down to the backing plate with nearly 100% of the pad gone. The outboard pad still had about 1/8" remaining. I inspected the inboard side of the rotor and felt some minor grooves. The outside of the rotor did not show any significant grooves or unusual wear so I was hoping to get by without turning the rotors.

When I test drove the truck after replacing all rear pads, the rubbing noise from the driver's side rear wheel was still present although not as bad. Is this possibly a result of the scoring on the inboard side of the rotor? I don't know if I should let the pads bed in for a few hundred miles or if that will damage them if the noise is in fact coming from grooves on the rotor. I used Delco OE pads and at $100/axle, I don't want them failing prematurely. Any input is appreciated. Thanks.

GM-Tech · October 22, 2005

We don't have any rust to speak of down here in the sub-tropics, so I don't see rusted dust shields, but yeah, that could cause your noise. Did you figure out how to get the shoes adjusted? The star should definitely turn more than 1/8th turn.

As for the front rotors... if you don't have a BIG puller that can handle it, a BFH. a Big freakin' hammer and lots of penetrating oil... Since you're replacing the rotor anyway.

An old trick we used when wheels were frozen in place was to leave the lug nuts a little loose and drive it 5-10 miles an hour and slam on the brakes. Do this a few times forward and reverse and it'd break the wheel loose. This method *may* help a little with a frozen rotor, but I never tried it, and the forces are not the same as on a wheel. I'd also be careful if you have aluminum wheels as loose lug nuts coupled with slamming on the brakes multiple times might cause some damage to the wheel.

gmcjoe · October 11, 2005

I know there is an issue with the right rear pads wearing unevenly.

I replaced my right rear rotor and the issue seems resolved

alvocado · October 13, 2005

How likely is it that the shoes simply need adjusted using the adjuster screw star wheel? Worse case, if this is related to a defective clip, do I need to replace the shoes on both sides or is it OK to replace just the side that is rubbing?

GM-Tech · October 13, 2005

How likely is it that the shoes simply need adjusted using the adjuster screw star wheel?

Slim to none.

Worse case, if this is related to a defective clip, do I need to replace the shoes on both sides or is it OK to replace just the side that is rubbing?

The shoes are available individually. It's okay to replace only the worn out side. This is only a parking brake.

Even though you're only hearing the one side doesn't mean the other side isn't in poor shape too.

GM-Tech · October 11, 2005

The rubbing noise is most likely the parking brake shoes INSIDE the rotor assembly. Pretty common. There's a little clip that holds the shoes in place that doesn't hold so well, allowing the parking brake shoe to lay against the drum portion of the rotor. This causes noise and wears the shoe out really fast. Your parking brake probably doesn't hold, does it.

The clip has been redesigned and comes with the new shoe, which can be purchased individually.

Light grooving of the rotors is not harmful and won't cause premature wear of the brake pads nor will it result in noise. Look at the parking brake shoes.

alvocado · October 14, 2005

I bought the Delco shoe kits this week from my dealer and plan to install them this weekend. The instructions that came with the kits indicate you should measure the inside diameter of the shoe assembly and adjust to 209.6 mm using the adjustor nut. I have no idea where to find a vernier caliper this large as that's almost 10". Do technicians at the dealerships bother doing this? My Haynes manual made no mention of adjusting the shoe assembly diameter to this spec.

The kit instructions also said to disconnect the parking brake cable at the pedal but the repair manual did not mention this. Is this necessary?

GM-Tech · October 15, 2005

Do technicians at the dealerships bother doing this?

Absolutely. Well, we do.

GM doesn't list a spec to set the shoe diameter, they list a spec for the difference between the drum and the shoe, which should be 0.026 in. I don't see how measuring the overall diameter of the shoe would be very useful since it doesn't account for the drum size, which can vary.

We use a gauge that GM calls for that measures the difference between the shoe diameter and the inside drum diameter. It's like a combined inside/outside caliper. First it goes into the drum where it's locked into the inside diameter of the drum. Then the outside portion of the caliper is used on the shoe. Adjust the shoe until the caliper just touches and it's a done deal.

You could probably make a good guess at this and come out okay. Adjust the shoe until the drum slips on with slight drag. Then back it off just a bit so there's no drag. 0.026" isn't much clearance.

You might have to disconnect the cables as described, but that depends. If you're sure there's absolutely no tension on the cables, you can leave them connected.

alvocado · October 24, 2005

It took 60 mins of pounding with a 20lb sledge hammer and a can of penetrating oil but I got both of the front rotors off. Thank goodness I bought new rotors in advance even though the originals looked like they were in decent shape. They were scrap metal by the time I got them off.

alvocado · October 11, 2005

The truck does move with the parking brake engaged so that might be the issue. Will I have to remove the caliper to change the parking brake pad and clip?

GM-Tech · October 11, 2005

Will I have to remove the caliper to change the parking brake pad and clip?

You have to remove the rotor since it's all inside there.

alvocado · October 22, 2005

I tried to install the shoes tonight and can't figure out how to adjust the diameter using the adjusting screw. When the shoes are in place, the star wheel only turns about an 1/8 of a turn and doesn't seem to affect the shoe diameter. Am I adjusting these correctly?

Also, I still hear some rubbing with the rotor on (unbolted) and it actually sounds like it's dragging on the dust shield. The shield is really rusted. Is this pretty common? The parking brake shoes needed replaced but maybe my dragging noise is actually from the shield.

alvocado · October 22, 2005

I think I have everything working on the rear and I'm pretty sure the rubbing when I test turned the rotors was from the junky dust shield. Once the tires were on and torqued, I don't hear anything so I should be in good shape.

I did run into an issue on the front brakes. My driver's side rotor is completely frozen on the hub. I beat it with a wood block and hammer for 20 mins and couldn't free it. Any suggestions on how to get it off without damaging anything? I'm replacing it so I'm not worried about saving the rotor itself.