Bruce M

Just changed my disk pads and found the inboard pads on the opposite side of the piston were paper thin while the piston side still had the grove in the middle of the pads.
What could the problem be?

seafish

Uneven pad wear is often caused by the brake pads not floating freely on the pins that hold them in place within the caliper. Often times corrosion and dirt build up on the pins or bores that the pins go through and prevent the pads from sliding freely AWAY from the rotors. Hopefully you cleaned everything up on the calipers really nicely and used a high quality silicone lube on the pins when reassembling with your new pads.

It is also possible that the the slave cylinder pistons are sticking and keeping a light pressure on the pads, though that problem more often shows uo as BOTH pads wearing quickly and/or overheating of the rotor. Cylinders not retracting is most often caused by brake fluid contamination from improper brake maintenance… i.e. NOT fully replacing and bleeding the brake fluid from the master cylinder thorough the calipers very 5 years at the most. MOST brake fluid is hygroscopic, meaning it adsorbs moisture, from the repeated heating/cooling cycles it goes through from regular use. Sooo…if you haven't done so for awhile. it's also a good time to replace and bleed the trucks brake fluid.

Dieselbuilder

calipers hanging up replace and clean pins and slider

samiam4

sticking piston will give uneven wear. Phenolic pistons it is not uncommon.

j_martin

I don't think these calipers have guide pins, but rails instead. They develop a notch in them and can prevent the caliper from centering. If it isn't severe, you can clean them up with a file. If severe, you have to add a little weld and then shape them to original. There's a writeup on it in the stickies somewhere.

A bad piston seal will cause excessive wear, because it doesn't allow the piston to retract the couple of thousandths of an inch that it needs to. It won't cause uneven wear, though. The uneven wear is caused by excessive friction or drag in whatever arrangement is used to float the caliper over the disk, be it pins, or rails and hold downs.

thrashingcows

I'm going through this right now on the crewcab. Drivers side is wearing fine, inside and outside pads are making contact fine. But pass side is hanging up and both pads are not engaging properly. I have cleaned caliper track surfaces of all paint and debris. There is a little bit of wear on the caliper brackets, but I don't think it's enough to cause any "hang up" issues. Everything looks good, but that one side refuse to work properly.

With the drivers side doing most of the front braking I now have a warped rotor as well...

diesel402004

X2 with seafish, but J_Martin is correct also--our calipers do not have pins. Both my trucks were experiencing varied examples of this, and new calipers etc. did not seem to be helping. Finally spent a lot of time cleaning up the channels and using anti-seize on the channels (great info on this in the stickies). Now my pads are wearing evenly and no pulling to one side.

NJTman

I had a similar issue until i brushed the calipers and mounting bracket and coated them both with ceramic brake caliper glide. its a purple gooey lube thats not affected by heat.

u2slow

I use neverseize on the sliders/rails. Seems to work.

One on my D250 got really worn... sloppy, and a notch from one of the pad 'horns'. I cut and bent up a piece of electrical box to use as a shim. Worked good for a quick fix.

I had a phenolic piston stick on the wife's Jeep. That made for a glow-in-the-dark HOT brakes ...not uneven wear.

thrashingcows

Got some of this today.

Going to bleed the front brakes, and check to make sure the piston is not hanging up in the bore. Also make sure I'm getting good pressure to the caliper as well.

KRB

Don't forget the rubber hoses. Are yours new? If not they can fail internally, swell and keep fluid from bleeding off.

MARF75

Maybe this is my problem, changed a caliper last weekend due to the piston seal being shot. Now in the morning when I first move the truck (10-20 degrees) it's like it is frozen down, I have to give it a decent amount of throttle to "break" it loose

j_martin

Take the wheel off and try to pry the caliper back. It should go pretty easy with a big screwdriver or pry bar. It probably won't.

Now disconnect the banjo fitting on the caliper and try again. If it goes easy, the hose is bad. If not, the caliper is bad. Warning, you could take a shower in brake fluid.

MARF75

when you say, pry it back, which way do u mean?

patdaly

Pretty sure he means pushing the pads and piston back into the bore.