Front brake pad uneven wear (inside pad worn, outside pad new)

[c3uo]

I have a 2016 Lexus RX450h with only 35,000 miles. I was shocked when I was told by the dealer that I needed new front brake pads. I told them I would do it myself and went home to look closer.

Well - see below picture. The outside pads are like new on the front, but the inside pads are completely worn. They are like this on both my front driver and passenger sides. Rather shocking for the age and mileage. The caliper and slide pins are not sticking and seem to be functioning properly.

My first Lexus after numerous BMWs. Thoughts? I bought the hybrid thinking it would never need brakes under my ownership. I've always gotten over 60,000 miles on a set of pads on my BMWs (easy driver).

 

[Popsy]

ATE brake system ?

 

[c3uo]

Pretty sure OEM is Advics (this was on the caliper casting) and RockAuto lists Advics for the OEM pads.

I've never had a Lexus before, but the pins / hardware / springs are typical Toyota.

 

[Popsy]

I've often seen this behavior on vehicle equiped with some ATE systems, Volvo, Fiat/Alfa, etc.

First thought was also stuck caliper pins, but on a vehicle this new...
Not experience with Toyota/Lexus to help, sorry, but curious to see answers about that.

 

[Ded Mazai]

Likely the pads don't move freely. Did you try to remove them from the caliper?

Toyota likes to put a lot of grease on the pads and the guides which works as a dust magnet. When I change pads I don't put any grease on the pads on anything exposed to dust.

 

[The Critic]

The pads are rusted/seized to the bracket. The fact that you were able to photograph both pads being in place (with the springs still attached) confirms this.

When the pads are moving properly on that bracket, the springs will eject the pads if you are not holding the pads with your hand.

 

[Rand]

Looks like they were stuck in place and not releasing. 3-4 salty winters seems like its possible

I usually end up redoing front brakes on the 2010 accent about every 2 years for this..

Since pads + rotors for that vehicle is under $100 it doesnt bother me much.. although I now use pastelub on the contact points and sil-glyde on the caliper pins.

Seems to work alot better than what I was previously using.

 

[incognito_2u]

Crazy as it sounds, whenever I see uneven wear of front pads, my immediate reaction is to check the Caliper pins.........being in the "rust belt" probably doesn't help much.
Toyota's have that pin with a rubber bushing on it that tends to swell up occasionally, especially if the wrong grease is used (obviously not the case as these are new).
Do a post Mortem on that caliper and tell us what you see.

 

[c3uo]

Thanks for the replies. As stated above, I expected the springs to "pop" the pads out, but they really didn't. The springs seem somewhat weak. I wonder if heaver duty springs are sold.

I've never worked on a Toyota / Lexus before, but the brakes were fairly heavily greased. More then I am used to seeing. That grease was fairly "chunky" with dirt / road dust.

I pulled the pads out, cleaned up the stainless steel pad retaining brackets, lightly greased the tabs, and worked the caliper slide pins. I did not pull the pins (didn't easily see how to pull the pin and was afraid to tear the boot), but the slide pins moved freely in and out once I "tapped" the caliper with my hand a bit.

The only reasonable conclusion is the slide pins were jammed, not letting the caliper float / self centre. Just disappointing on a 2016 Lexus with such low mileage.

That said, I expect I'll be pulling the caliper bolts / slide pins twice yearly when I switch my snow tires now....

 

[Ded Mazai]

There is no reason to re grease the pins unless you really want to. Factory grease stays good for at least 8-10 years. The boots will slide over the pins when you pull the pins out. Try to rotate the pins first to make the boots loose.

 

[geeman789]

Originally Posted by c3uo


... That said, I expect I'll be pulling the caliper bolts / slide pins twice yearly when I switch my snow tires now...



I believe that in any climate with winter and salt, yearly brake inspections / plus clean and lube are very helpful in prolonging brake life. Past and current cars taught me lessons about rust jacked / binding pads, seized slider pins, swollen slider pin bushings etc.

And, when these problems were noticed and taken care of, the brakes worked much better ... !


Note: Do those pad spreader springs really do anything ... my Honda Pilot has them on the back, but they seem to have forgotten them on the fronts ... pads have the holes, but springs are noticeably absent.

 

[mk378]

Rust underneath the stainless guides will pinch them in, preventing the pads from moving freely.

 

[Hall]

Originally Posted by c3uo
I did not pull the pins (didn't easily see how to pull the pin and was afraid to tear the boot), but the slide pins moved freely in and out once I "tapped" the caliper with my hand a bit.

For future reference - sounds like the slide pins are fine at the moment - just pull harder. Use one hand to hold the rubber boot and pull the pin out with the other. Nothing really secures it in there. There will be suction only holding it. When you put the pins back in, just squeeze the boot up against the pin and it should 'hook' on it's own.

 

[CharBaby]

Originally Posted by The Critic
The pads are rusted/seized to the bracket. The fact that you were able to photograph both pads being in place (with the springs still attached) confirms this.

When the pads are moving properly on that bracket, the springs will eject the pads if you are not holding the pads with your hand.

Originally Posted by Rand
Looks like they were stuck in place and not releasing. 3-4 salty winters seems like its possible.


This^^^

After removing the pads and hold down bracket, grind/file clean the area where the ears of the pads slide into the hold down bracket and then lube the area prior to installing new hardware. Yes, install new hardware!

 

[Lubener]

Inside pad worn more likely is a caliper hanging up, outside pad usually is binding slides and or hardware.

 

[c3uo]

I just took apart the drivers side (the picture was the passenger side). Tried to be slow and methodical in my disassembly. The lower slide pin was bound. Not badly, but enough to likely cause the issue. It was well lubed and clean once I freed it up. I expect that the soft driving and hybrid generator braking led towards the brakes not being used much so the lower slide pin was stuck. Understandable, but disappointing in such a new low mileage vehicle. The OEM pads are Advics.

Any recommended replacements for low dust and good performance? Akebono, Advics, or Raybestos Element 3 are the ones I'm looking at....