The Stovebolt Site Forums The Shop Area Driveline Abnormal disc pad wear.

Saturday I had to change disc pads on the left side of the Suburban in a motel parking lot. One pad was down to metal and scarring the rotor. I decided to wait until I got it in the shop to do the other one since I was only about 200 miles from home and that side wasn't scarred.

Today I looked at the right side and the thinnest pad has 3/16" of meat left. That is a touch over half of what is on the new pad.

These pads only have 25,000 miles on them. I wasn't expecting them to be worn this soon. My F250 had lots of meat left at 77,000 and it pulls a travel trailer. The right one on the 'burb looks like it would go at least another 20,000.

What would cause the abnormal wear on the left?

Caliper slides holding it from returning? Brake hose with a slight restriction not letting caliper fully release? I would start by taking the pins and slides out and cleaning them good, then lube them up and I would also shine up the area on the spindle that the caliper slides against and also the caliper side and then lube it up when it goes back together. Take it for a good ride and get the brakes heated up a few times and then when you get back to the shop jack the front end up and spin each wheel, see if they both feel the same. Good luck, Don

Inboard pad or outboard? Usually, an excessively worn inboard pad will indicate a sticky piston or a collapsed hose, either one not causing the piston to retract and pull the pad away from the rotor. Outboard wear is usually a slide pin problem.

It is the outer. I'll take it back apart tomorrow and clean and lube as directed.

Thanks for the help.

Further inspection revealed the caliper cylinder is not releasing. With both pins removed it was still grabbing. I had to rock it a bit to get it loose.

What would cause that?

If it needs to be replaced Do you replace the whole unit or buy a kit?

The pins and bushings do need a good cleaning. What kind of lube should I use on assembly?

Sounds like a combination of a hung up piston in the caliper, combined with a sticky inboard pad. Generally, I would suspect trash in the cylinder bore, possibly from a failing hose.
My opinion would be to replace both calipers, as you can usually get a new/reman calipers for about the same as what you would spend on a kit + time spend overhauling. Plus, they'll have all new hardware and pins. On brakes, you always want to do the same on both sides to ensure even braking. A pair of hoses would be a good idea, too. For the lube, Permatex has a synthetic brake lube that's the best I've used. It comes in a green labeled bottle, but it can also be found in small packets (like what ketchup comes in at the local burger place) in their "Counterman's Choice" rack. It's a somewhat thick dark green lube, real sticky. But it's very slick and stays in place.
One more thing, I'm not sure just how the mounting you're using is setup, but you might go over the areas where the pads ride with a file to square them up, sometimes that will make a pad hang up.

Cletis,,
I went though this as well. My guess would be a cheap casting or poor rebuild of the caliper provided in the disc brake kit. If the kit is from CPP, the part is guaranteed for life. Good luck with that.

I tried to use a caliper off the shelf from a local parts house. The cpp caliper uses a different pressure hose connection thread than the stock gm caliper. So if you are trying to get one off the shelf, make sure the threads match.

OK, this is the POL kit. I don't know if they use the same calipers or not. Pads for a 1980 Chevy half ton matched up.

Bill, I found one of those little packs of lube under the second set of pads. It is VersaChem brand. When I by some I'll look for the Permatex.

John thanks for the tip on the mis-match. I think I'll take Bill's advice and replace hoses too so I should be able to get a match.

I cleaned and lubed the pins on both sides and the left is still tight. I'm going to run it like that until January. I have too many events scheduled to tear it down now. It is stopping well and I don't see it damaging the rotor any further. I'll get it turned and new calipers and hoses then.

Thanks to all of you for the education on discs. I never really stopped to think about how do these things work.

Cletis,I just put the cpp kit on my suburban.
This is what the tech guy told me was used in the kit.

1.Calipers 73-87 Chevy 4x4 ½ ton
2.Brake pads 73-87 Chevy 4x4 ½ ton
3.Rotors 73-87 Chevy 4x4 ½ ton
4.Booster 8” street rod booster life time warranty
5.Master cylinder 67-76 corvette lifetime warranty
6.Proportion valve (combo valve) 70’s Camaro life time warranty


Tim