Analyze this brake pad wear

[The Critic]

These rear pads were pulled from a 2008 Acura TSX with 57k. They are Genuine Honda pads, but I suspect that they are not the original. One of the inner pads measured 2.5mm, which is why I recommended replacement to the owner.

The caliper piston was lined up properly at 90deg, and the caliper appeared to slide freely. So, I think we can rule out those two areas as the cause of the abnormal brake wear. I also did not re-lube the caliper slide pins at the time of the brake job, but I may go back and do so.

However, I noticed that someone had applied some Molykote M-77 onto the pad retainer clips. Nowhere in the factory service manual is this recommended, which is why I suspected that a dealer tech had done a rear brake job on this car at one point. This resulted in a thick, sticky layer of gunk that prevented the pads from sliding freely.

I spent quite some time cleaning these clips and the new pads now slide very freely on the pad retainer clips; could this have been the cause of the angled wear?

Without further delay, here are the pictures:

Honestly, the angled wear is not that bad, it is worse than what I am used to seeing it. All of the pads that I have replaced before looked perfect; this is the first time I have seen pads that have some angled wear. I think the M77 that was on the pad retainer clips caused this by not allowing the pads to slide freely - and was the only problem with the caliper.

What do you guys think?

Thanks.

 

[DemoFly]

Normal

 

[LargeCarManX2]

Single cup or dual cup?

 

[LeakySeals]

More wear in the center where the caliper piston depresses the pad. That would suggest the metal bracket/backing the pads are riveted to was flexing/bending. Maybe a stronger/thicker metal pad bracket/backing would prevent flexing and provide more even wear.

 

[The Critic]

Originally Posted By: LargeCarManX2
Single cup or dual cup?


It is a single-piston rear caliper, if that is what you are asking.

Originally Posted By: LeakySeals
More wear in the center where the caliper piston depresses the pad. That would suggest the metal bracket/backing the pads are riveted to was flexing/bending. Maybe a stronger/thicker metal pad bracket/backing would prevent flexing and provide more even wear.


That could be possible. I installed a new set of Genuine Honda rear pads again since I did not replace the rotors.

 

[Trav]

It appears to be binding at one end of the caliper bracket on a single piston unit. It could be rust buildup under the clip.
I would think any flexing of the backing plate could cause cracks in the pad material.

 

[sciphi]

Looks normal to me.

I've used NAPA's synthetic brake pad grease on several brake maintenance jobs, and had no issues with sticking. Rust, though, is another story. The clips always get cleaned thoroughly if they're being re-used.

 

[spackard]

Molykote M77 has been recommended in other Honda applications.
http://www.skidmore.edu/~pdwyer/e/files/tsb/a03-033.pdf

I thought it was normal to use it to reduce the chance of a squealing noise. In the above TSB it's used to reduce the clicking noise when you've changed from forward to reverse (or visa-versa) and apply the brakes.

 

[Bgallagher]

Originally Posted By: DemoFly
Normal


+1

Good sale on Jimmy Dean in the first picture. Hope you took advantage of it..

 

[mechanicx]

Yeah I've always seen Honda service info show applying molycote to the pad ears which contact the pad anchor clips. Now if molycote was applied to the back of the clips between the anchor that may cause a build up problem.

I'm not sure why the molycote dried up. Maybe the brake got too hot and maybe someone drove some with the parking brake applied or whatever. The pad wear looks about normal to me though.

 

[PandaBear]

Normal, but if you want perfect wear you should get new piston pins, hardware, and bushing/rubber, and lube it well.

p.s. those 98c soda seems to be a very good deal.

 

[hattaresguy]

That looks about right for a single piston sliding caliper. Lube up the calipers, bleed out the old brake fluid and your GTG.

 

[mattd]

Seeing brake wear day in and day out, that is not normal wear.

I agree with Trav. Looks like one end of the pad got stuck in the bracket from excess dust or rust, given the caliper is functioning properly.

 

[The Critic]

Originally Posted By: mechanicx
Yeah I've always seen Honda service info show applying molycote to the pad ears which contact the pad anchor clips. Now if molycote was applied to the back of the clips between the anchor that may cause a build up problem.

I'm not sure why the molycote dried up. Maybe the brake got too hot and maybe someone drove some with the parking brake applied or whatever. The pad wear looks about normal to me though.


I am looking at the 04-08 TSX Honda service manual and there is no mention of applying M77 to those areas. The only areas that it is recommended is on the pad backing plate, and the front/back of each shim.

There was a thick layer of molykote on the pad retainer clips that the pad ears sit. Overtime this became fairly sticky and IMO, prevented the pads from sliding smoothly. Once I had those clips cleaned up, the new pads slid so freely that they could easily fall out...
Originally Posted By: Trav
It appears to be binding at one end of the caliper bracket on a single piston unit. It could be rust buildup under the clip.
I would think any flexing of the backing plate could cause cracks in the pad material.

In that case I think I probably fixed it. The surface of the clip was so heavily caked that the pads were sort of sticking.

Originally Posted By: mattd
Seeing brake wear day in and day out, that is not normal wear.

I agree with Trav. Looks like one end of the pad got stuck in the bracket from excess dust or rust, given the caliper is functioning properly.


Agreed, thx.

 

[Scott_Tucker]

What was the complaint from these brakes?

 

[The Critic]

Originally Posted By: Scott_Tucker
What was the complaint from these brakes?


They were starting to squeak, and I measured 2.5mm remaining in pad material on the lowest pad.

 

[mechtech2]

That is a bit abnormal for most cars.
But some calipers do not slide the same on both pins -- they are not inherently equal.
Different lengths - metal to rubber vs. metal to metal -

 

[The Critic]

Originally Posted By: mechanicx
Yeah I've always seen Honda service info show applying molycote to the pad ears which contact the pad anchor clips. Now if molycote was applied to the back of the clips between the anchor that may cause a build up problem.

I'm not sure why the molycote dried up. Maybe the brake got too hot and maybe someone drove some with the parking brake applied or whatever. The pad wear looks about normal to me though.

So I reviewed a few Honda TSBs and the FSM instructions.

http://www.import-car.com/article/83546/...ing_noises.aspx

Molykote is to be applied BETWEEN the bracket and the pad retainer clips. This is only done per a TSB, but I do not see how it can be of any harm. The FSM further specifies to apply a small amount to the pad ears.

On this car, someone applied M77 to the entire area of the pad retainer clip that is exposed, not to the area between the pad retainer clip and the bracket. That is how the buildup issue occurred.

 

[mechanicx]

I think it depends on if the brake caliper assembly is a Nissin or Akebono design. With Akebono the M-77 is applied to the brake ears and between pad and clips and with Nissin M-77 is applied to the between the bracket and clips and I guess some to the pad ears. That's my recollection from the service info.

I'm not sure why the two types have the M-77 applied differently, but I'd thought I always seen M-77 to be appled to the pad ears and clips. I'm guessing your application has nissin claipers.

 

[mechanicx]

Scratch what I just said. I just looked at service info but not TSBs and it said M-77 to the bracket and to the pad ears but not to the pad-side of the pad clips (retainers) . I misread the information quickly a few days ago about where to apply M-77 with the two caliper types.

I'm guessing applying M-77, especially too much, to the pad retainers on the pad side could collect brake dust and cause some binding whereas with applying it to the bracket it's covered by the retainers.