Uneven brake pad wear

[JMHC]

On my 07 Accord V6 I noticed some noise and excessive brake dust on the driver's rear wheel a few months ago. Upon inspection, I noticed the outboard pad was totally gone while the inboard pad was fine. The passenger side was fine. The pads were stuck in the bracket so I assumed it was just rusted and seized up. So I replaced the pads and shims, with lots of high temperature lube on the pads and sliders. The piston seemed to retract fine, it is the style that rotates back as it is integral with the parking brake. Fast forward to yesterday, and I can smell the driver's side brake burning after driving on the highway. I looked at it again, and this time the pads were free and the sliders fine, but the outboard pad was wearing faster again. The piston was very hard to retract this time.

So here's my question...typically inboard pad wear is caused by a sticky piston, and outboard is caused by seized sliders. Could it be that I am having outboard pad wear due to a sticking caliper piston? Either way replacing the rear calipers should fix the problem. It's hard to believe the sliders could seize every few months after lubrication...they seemed to move fine yesterday when I checked.

 

[Donald]

Most mechanics would say if the piston can be pushed back in the caliper with a clamp the caliper is not seized. But that comment may not be valid if the parking brake is integrated. Maybe you need to clean and lubricate the assembly where it rotated back in to retract. Maybe a parking brake cable problem.

 

[SIXSPEED]

Strange that the outboard pad would wear more since initial force of the piston is applied to the inboard pad. I would have guessed the guide pins are sticking but you already checked that. Typically there is a slot on the piston face that needs to align with a pin on the back of the inboard pad; did you check that?

 

[KrisZ]

How are the sliding surfaces on the bracket? Make sure that the pad is not getting "wedged in" and don't put too much lube on them.

 

[The Critic]

As usual, did you wire brush the clips and the area on the bracket that the clips sit on?

On the last brake job that I did for this generation of Accord, the pads fit VERY loose on the bracket once everything is cleaned up.

 

[mechtech2]

If the piston was hard to retract this time, the you have it narrowed down.

 

[vssjim]

the piston being tight doesn't sound good at all but the hanger may need to be removed hardware taken out and with a file clean off rust to be sure pads as really loose in caliper bracket before condeming caliper, also make sure caliper pins are lubed with non petroleum lube as not to swell up rubber parts.

 

[Tegger]

Originally Posted By: JMHC
On my 07 Accord V6 I noticed some noise and excessive brake dust on the driver's rear wheel a few months ago. Upon inspection, I noticed the outboard pad was totally gone while the inboard pad was fine. The passenger side was fine. The pads were stuck in the bracket so I assumed it was just rusted and seized up. So I replaced the pads and shims, with lots of high temperature lube on the pads and sliders. The piston seemed to retract fine, it is the style that rotates back as it is integral with the parking brake. Fast forward to yesterday, and I can smell the driver's side brake burning after driving on the highway. I looked at it again, and this time the pads were free and the sliders fine, but the outboard pad was wearing faster again. The piston was very hard to retract this time.

So here's my question...typically inboard pad wear is caused by a sticky piston, and outboard is caused by seized sliders. Could it be that I am having outboard pad wear due to a sticking caliper piston? Either way replacing the rear calipers should fix the problem. It's hard to believe the sliders could seize every few months after lubrication...they seemed to move fine yesterday when I checked.

Your description is consistent with rust on the caliper pistons. Rotate the piston outwards almost all the way, then pull the dust boot back and look for this...

If you find rust, it's time for a rebuild or a replacement. A DIY rebuild is more fun.

 

[JMHC]

Thanks for the input guys...it is strange if it is the piston for the outside pad to wear. The last time I did the job I put new sliders/clips in place and greased the edges of the pads. So that was all new just a few months ago. That time the pads were wedged in place, which I thought was the issue, but this time they popped right out. I guess it does seem that even with outer pad wear it must be the piston...but I will check under the boot. Oh yes, and I did have the slot on the piston aligned with the nub on the inner pad. Might be time for new calipers, which also come with new brackets and sliders. That ought to fix it either way...I have wanted to rebuild them myself, but finding the time is tough!