I replaced my front rotors and pads on my 2001 5.4L Screw 1 week ago. Everything has been working fine, but I just happened to look at them and noticed that the wear on the front rotors doesn't look right. You can see there is no rust forming on the outer edge of the rotor (thank you Minnesota winter for giving visible rust in < 1 week). See the pic below.

The wear looks too far out on the rotor, and not in the middle. Here's a pic from the rear rotors that shows what I expected the fronts to look like:

Did I maybe do something wrong installing the pads? Could this just be a different wear pattern from different pads? Not sure what brand was on there before, but I just installed the Wagner ThermoQuiet semi-metallic pads. I'll have some time this weekend to pull the wheels off and inspect it a little closer.

 

I would think pad installation is pretty straight forward, pretty hard to install a caliper incorrectly. Maybe your new rotors are the wrong size? If you still have the old ones measure them. it wouldn't be the first time the wrong part has been sold at parts store.

You will probably find your pads not wearing at their outer edges.

 

Unfortunately I don't have the old rotors anymore, so can't do that comparison. Does anyone else who has the Wagner TQ pads get this type of wear pattern?

 

Are both fronts the same?
One thing I've see is the pads not setting in the caliper correctly.
Some times its a shim or one of the other parts hanging up.
Check the inside wear as well.
You did pull and clean/lube the guide pins? or replace and lube new guide pins?

 

Yeah both fronts have that same wear. I pulled the existing pins out and greased them with that blue grease. I'm pulling the tires off tomorrow morning so can get a closer look.

 

I pulled off the wheel and it looks like the rotors must have been the correct size. There's not too much clearance between the caliper and rotor.

Pulled off the caliper and the pads look like they were still seated just fine. They come right out to the very edge of the rotor.

The back sides of the rotor seem to be wearing a little more evenly, but both sides seem to be wearing on the outside of the rotor more than the inside. Kind of like the caliper is maybe pushing more on the outside maybe? Do you guys think it'll be fine once the pad wears down a little and makes good contact with the rotor all around, or is something out of whack here?

 

I was just reading about "runout" - could this be what's causing this? Still learning exactly what that is...

 

Just a thought, but I don't see any evidence that you cleaned where the two ends of the brake pads slide in and out as brakes are applied and released. The front pads may be hanging up on the rust. Did your give one good hard brake to seat the pads real good? That may straighten them out. You could also put a thin coating of grease on that surface also so that they release easy when release the breaks.

Also, check the slave pistons to ensure they are straight. It looks like the pistons are hitting the pad harder on the outer edge.

 

Greencrew, are you talking about putting some grease in the channel of those end clips? I did install new clips when I put in the pads, but didn't see anywhere that needed to be cleaned out - maybe I missed something? I did about 4 semi-hard stops from about 40 mph down to 5 right after I installed them, but I guess I could do a little harder of a brake and see if that helps.

What are the slave pistons? I've got the 2 pistons that push on the inside pad, but on the outside pad the caliper just has some "fingers" that hold the pad in place.

 

Those two pistons are the slaves. They should sit flat on the pads. Are they?

 

Didn't think to check that when I installed them - will have to try and look tomorrow (yikes, I guess later today...).

 

2WD or 4wd

2wd/Were the Rotors torqued to specs?
4WD/Hub surface cleaned? so the Rotors sit flush.

A couple a posters made some very good suggestions.

Were the slide Pins removed and CLEANED, and clean the channels the pins go into, they need to slide in and out easily so the calipers are able to float to apply even pressure when braking. Sticky slides pins mean uneven pad wear, maybe also causing rotor overheating and possible warping.

Before you installed the new anti rattle clips did you clean the Caliper bracket to remove the rust. Rust expands metal thickness, which means you pads will not slip into the anti rattle clips easily, which means the pads will not float when brakes are released again causing uneven pad wear and possible rotor overheating and possible warping.

Hope this helps

 

Thanks for the help guys.

From what I can tell visually they are pushing on the inside pads ok. I'm not really sure how else I could check that.

I have a 4WD.

I had the rotors off for ball joints about a year ago and cleaned the hub surface up and applied some anti-sieze on there. When I took off the rotors this time the hub surfaces seemed ok so I didn't scrape on them much at all.

I removed the slide pins, wiped them down, and greased them but did not do any more additional cleaning on them. This would be an easy thing to redo I guess - just need to buy another $1.29 grease packet.

I did not clean any rust off the caliper bracket. The pads did go into the brackets very easily - no force required. I'm fairly certain they would slide in/out with no problem.

Sounds like cleaning the slide pins better would be a good idea. Guess I'll try that and see how things turn out.

 

Oddly my back have this odd wear pattern, not my fronts but I am 2wd. Also this seams to be a normal pattern on my backs as the original ford rotors wore out from outside in, it may have to do with the way the calipers grab the rotor. I had one bad rotor in the back that wore down to metal on the inside but the first part to rub was the very outer edge of the rotor. My new rotor has identical wear pattern so i accept it as normal.

Just make sure you pull the slide pins out clean the heck out of them old lube dries up and it becomes sticky or hard and the caliper will not return to center. Brake clean is your friend so is caliper lube.

I use synthetic lube. i purchased it in a small bottle and it comes with an applicator brush.

 

OK, good news is the inside pad that is applied with the caliper pistons is wearing even.
Still have a problem with the outside pad.

I can't tell from the pictures - are your calipers aluminum or steel?
If aluminum you could have caliper spread. It happens over time and the only correction is to replace the caliper. I have to change the ones on the race car about once a year because of it.

Another thought - is it possible to swap the inner and outer pad? If so do it and and drive for a few days and see if the pad / rotor wear evens out.