Due to the back rear brake noise, we took both rear wheels off. We found that the inside brake pad was completely gone and the caliper piston was pushing against the rotor when pressing the brake. Small part of the piston was shaved off. This is the rear driver side. The rear passenger side is not as bad but the inside brake is worst then the outside. So, what could've caused the inside brake pad to wear out much faster than the outside? This is on my 2015 GS 350.

 

Could have been some real cheap brake pads? Also a hung/stuck frozen Caliper does this. One other thing I see people do here and on FB which is Dumb is to put Shims on Top of Pads that are designed with built in Shims like Akebono's.

 

Root Cause: Driving conditions that saw perfect oxidation and rust in integral parts of the braking hardware and caliper aka salt exposure.

You need to inspect your brake hardware and caliper more frequently if uneven pad wear is a problem.

 

Looking to do my front brake pads. Anyone know the OEM brake pads for the F sport?

I was deep cleaning the OEM set of rims today and the front rims were totally caked in heavy brake dust on the wells. The face of the wheels were not too bad.

 

I have a 2018 F-Sport (AWD). Mine were:
Front Pads: 04465-30510
Anti-Squeal Shim Kit: 04945-30360

 

Stuck caliper. If the caliper was damaged as you describe it's time for a new caliper. Otherwise check to see if the caliper piston freely moves when you try to close it. If so it may have been a small piece of road debris that caused it to stick, or the slide pins weren't properly working. If that's the case you could probably get away with reusing it after putting on new pads and properly installing it, just check it frequently to make sure it's not binding with the new pads. If it were my car though I would just replace both calipers and be done with it.

 

Yep. In the avalon, Piston rubber seal had small tear, which I finally saw. I rebuilt that with OEM kit (got a rebuilt caliper as backup, returned it). I have not had to do brakes since I got this Lex from my cousin after having done brakes only 6 mos before. All my other vehicles with such issues were due to bulging slider pin bushing, air in boots, or hardware not sliding due to grease. If you feel one wheel center/lugs hot as you walk by is worth checking. If you are able to lift wheels of ground at center, spinning both sides wheels is a good check. And everything Pogmothoin mentioned. These one-sided pad wear or diag pad wear is hard to see.

 

Thank you for all the help!

 

For anyone doing brakes, I recommend deep cleaning the wheels and calipers. If dust build up is too high, the entire wheel area will hold extra heat which will lead to faster component break down. Remove the rims, deep clean the wells, coat it with a ceramic, deep clean the brakes. If I had to price this out, this is a $1500 job easily, on top of the brake job. But if you regularly clean your car, the components shouldn't be too difficult to clean.

 

I had a similar thing happen on my car, '14 AWD, and it's a timing thing (and lack of maintenance on yours). While Pascal's law is always valid, there is always pressure loss due to friction while the fluid is MOVING. What ends up happening is the inner pad ALWAYS touches the rotor first, then the caliper moves and the outside pad contacts the rotor. THEN then caliper can actually squeeze the rotor. It will always squeeze the driver's side (LHD) first, then the passenger side.

The pads are also not that long, so it is easy for them to drag on the rotor when initially touching and when the caliper backs off. If the caliper actually sticks, you'll have TONS of material on one pad, and wear out the other. Your rear brakes must've been screaming for a long long time before the backing plate slid out of the caliper.

This reiterates how important it is to inspect your pads through the window of the caliper every time you rotate your tires... which should be every 6-8kmi.

You can help the pad from getting cockeyed and return better if you use the orange "Disk brake quiet" stuff on the back of the inner pad. It'll glue the pad to the piston so it'll return evenly every time too.

My story is I chased a squeak in my brakes, so i lubricated the front pads. They were nice and quiet for about 3mo. Then happenstance happened, and they squeaked again when cold. This went on for a while... then my brakes started squeaking backing up. After about re-lubing the brakes up front and still hearing it I pulled my back wheels off and found the culprit. I'll never let the rears get below 4mm again, because that's what they measured a few kmi before this all happened. The edge of the backing plate must've gotten hung and started eating it up! The inner pad is glued to the caliper piston now.