Uneven brake wear

Hey everyone,

My brakes just started squeaking a few days ago, and I’m only at 30,000 miles. I ordered a set of PowerStop pads and rotors to replace the stock ones, figuring it was time anyway. When I pulled the front driver-side pads, I noticed the inner pad (engine side) was significantly more worn than the outer one. Oddly enough, the outer pad—with more material left—is the one that has the wear indicator.

I cleaned and lubed everything up, swapped the pads, and reinstalled them, but after a test drive, the squeak is still there.

I do a lot of stop-and-go and mountain driving, so I’m wondering if the caliper or slide pins might be sticking. I’ll take apart the passenger side today to compare, but with the uneven wear, I’m thinking it might just be time to throw on the new PowerStop set.

Anyone run into a similar issue? Should I throw on the new set?

 

Your vehicle has fixed - not floating - calipers. Floating calipers float on slider pins which can seize up and cause uneven pad wear. Fixed calipers do not have slider pins and instead rely on the action of the pistons on each side of the caliper to balance pad wear. I believe you will find that one side (2 pistons) of your caliper is starting to seize up.

 

is it me or does that upper slider pin look bent?

 

It kinda does look like it's bent a little but that could just be a shadow on it. What does concern me is the scoring marks on those pins, more so on the lower pin as those marks extend beyond where the pads would travel when engaged...seems to indicate a prior pad was worn well past the current set, like all the way down to the bone.

@Mmacro, Squeaks n squeaks can sometimes be associated with that thin shim plate between each piston head and pad. Volvo's are notorious for their squeak/squeals and some disk brake quiet helps.

 

I’ll take them apart again today and take a look. Any tips for fixing this or is replacement my only option?

 

Ill check when I pull them out today but I think they are straight. This is a screenshot of a video.

 

That scoring is from me cleaning it with a wire brush. These are the original brakes. Total of 30k miles.
I’ve heard of the squeaking originating from the shim plate. Ill try some disk brake quiet.
Interestingly, they only seem to squeak when they’re cold.

 

To me it looks like a camera angle thing.

 

Is it under warranty? Does that cover brake noise?

 

One can rebuild calipers, and the parts are readily available at your local Toyota dealership if you want to. The parts are fairly inexpensive. The process is not difficult, but you do have to know what you're doing. As an alternative, you can buy remanufactured calipers at the dealership, and they use Toyota OEM cores and rebuild parts. You can also buy new OEM calipers for more money. A less desirable alternative is to use parts store remanufactured calipers, but they use lower quality rebuild parts and the cores can be OEM (rarely) or lesser quality aftermarket (more likely) and in my experience, they don't last nearly as long. There are also new aftermarket calipers available now, but I don't have any experience with them.

 

OP, how many miles are on your car and what year is it?

 

It’s pretty normal to have the brake pad on one side wear quicker than the other. I wouldn’t worry about it. You still had quite a bit of life left in those pads too.

 

Swap them around to even out the wear?

 

That’s probably not a good idea. Just run them until the inner pad is almost completely worn out and then get new ones.

 

Here you go if you DIY anything

https://www.4runners.com/threads/brake-replacement-parts-list-5th-gen.34536/#post-506124

 

I'm the kind of dork who actually measures the pad thickness with every wheel rotation (every 5K miles when I do the oil and driveshaft).

Mine have worn evenly, front and rear, for the last 60K miles.

Time to dig in. Wire brush around the pistons BEFORE pushing them back into the calipers. New pads. Wire wheel the pad pins and make sure they're not bent. Reinstall and monitor.

Not a whole lot to be gained by a forensic investigation at this point. Assume pin bent limiting travel or sticking piston/puck and move on.

Jason

 

^^
If you wire brush around pistons, do it gently. Don't rip holes in the dust boots around the pistons.

If you are in warranty, ask dealer to check. Pads are normally a wear item not covered but uneven wear is sign of possible issue that should be covered. If you are outside basic 36month warranty, I don't know if brakes covered by the longer 5yr/60k powertrain warranty period.

 

Good point. Thanks.

I use a brash brush like below.

Jason

 

Use a nylon toothbrush!

 

Do you bleed the old water contaminated brake fluid out the bleeder valve often?
I always open the bleeder valve when pushing the pistons back to make room for the new pads.
If you suction the old brake fluid out of the reservoir first. Then bleed each caliper as you install new pads you will have a refreshed brake fluid system.

 

Inner usually wear more than outer pads being closer to caliper pistons. I have a Limited and my i rear inner driver's side pad has only been lasting about 30-40k. I have Powerstop brakes and mine squeal first thing in the morning cold, but it goes away after rotors warm. I think it may just be the carbon ceramic pads being cold and rotors start rusting overnight depending on conditions. I bought used and I only have one spring on the caliper pins in front. They push the pads away from the rotor after caliper releases. I have replaced rears twice and my front have plenty of pad still. My mom had a Honda that did the same thing.

 

When you end up replacing the brake pads and rotors, make sure you buy new pins and springs to go along with it.

I like to add an additional spring on the upper pin.

I doubt it has anything to do with your issue, but it appears that you might be missing this spring

 

Clean your pins. I usually use some Permatex synthetic brake grease very lightly, but didn't this time. I probably had 20k left on all the rear pads, but one had no pad left, just backing plate.