Interesting rear pad wear pattern

Joined
Aug 5, 2002
Messages
21,417
Location
Silicon Valley
97 Integra, 270k miles. I don't remember when was the rear brake replaced last time but it has to be at least 8-10 years ago, but probably only 30k miles or less.

The rotor has worn down a bit, with some scoring about 1mm deep, matching left and right rear rotor wear. Same for the pads on the outer sides (outer left rear and outer right rear), with about 4mm left when I replaced it. The Inner sides of the pads (inner left rear and inner right rear, the one touching the caliper pistons) is the interesting one. The wear is tapered and the lower edge of the pads are worn to almost touching the wear indicator noise clip thing, the top of the pad still has about 6mm or so left. If I have to say in percentage compare to a new set of pad, the bottom is worn to about 20% and the top is about 50% remain.

Another interesting pattern is, the close to center of the rotor side of the pad wears out less than the close to circumference of the rotor side of the pad. It is almost like the braking is done at an angle and the pad is not pushed down by the pistons straight into the rotor, however the opposite side of the piston, the clamp was able to push it down fairly well.

I don't remember what pads I use, I think it is some sort of Wagner CX stuff off rockauto clearance.

I checked the caliper pins and they "move", not much difference between top and bottom, and the inner pads wearing symmetrically between left and right, the outer pads wearing symmetrically between left and right, tells me it is not something "broken" or "stuck", but rather either something is wrong with the pads or the rotor wear (i.e. the rotor is not flat but somehow turned into mild cones).

Has anyone seen this kind of pattern? I have seen tapered wear on the rear before and it wasn't this bad. I am wondering if it is because of uneven front and rear friction rating, or if the wear pattern has anything to do with rotor not being turned and new pads just slapped on.
 

PandaBear

Thread starter
Joined
Aug 5, 2002
Messages
21,417
Location
Silicon Valley
Measure the rotor thickness across the full pad contact area to rule out improperly machined rotors.
It was the original rotors came with the car, never changed never machined for 270k miles. I can tell it is already worn down a bit (1mm).

The inner pads didn't move freely enough in the carrier and dragged a bit.
I guess that's probably what happened, the last pads didn't come with hardware brackets and was just a quick $12 pad slap if I remember right. I did clean it and reapply lubes but I guess it is not good enough.

This set was a closeout from Pepboys that comes with every hardware possible.
 
Joined
Aug 30, 2004
Messages
28,656
Location
CA
I guess that's probably what happened, the last pads didn't come with hardware brackets and was just a quick $12 pad slap if I remember right. I did clean it and reapply lubes but I guess it is not good enough.

This set was a closeout from Pepboys that comes with every hardware possible.
The lube is probably what caused the issue. It will attract dirt and clump up, which causes the pads to stick. If you use any lube, I would only apply a barely noticeable film onto the pad ears.
 
Joined
Aug 23, 2010
Messages
3,974
Location
pa
removing, cleaning + lubing caliper slide pins is a good practice, depending on your climate where you drive more often is better IMO. i just put NRS quality $100 pads on my 2011 fronty SV + the EBC yellow pads that braked well but short lived at only 23 thou were worn crooked + i cleaned lubed everything only 3 years ago upon install of EBC pads + rotors!!
 
Top