Rear Brake pad wear

[GeoffM]

I was in the process on disassembling my hub (decided not to), and when I took off my fairly new brake pads, I found this! It looks like uneven wear but I don't know what to make of it. Any ideas? This is right rear which is a new caliper.


Looking at it now, there is some crud from the garage floor on it. I'm talking about the area next to my pointing and middle finger.

[accordztech]

so the wear on it looks like a few things. The ring on the outermost part of it is consistant with not resurfacing the rotor when putting the new pads on. The rotors edge dug into the pad causing that.

I cant tell if its uneven or not by the color of the whole pad, but if it is the unevenness it can be either you didnt break in the pads and you just started slamming on them and didnt drive normally, the lift from the edge of the rotor interfered with it, or your caliper guide pins wernt greased making one side stick.

[James Matteu]

Connecting the dots

Look at the big picture, remember my response in your other thread (see below)? This is more evidence that supports the idea that your parking brake was not properly reset after the pads were changed.

Helms states the parking lever must be pulled several times to set the mechanism, this is after the piston has been backed into the caliper for pad replacement. I suppose it is possible that the caliper has never been properly reset, though it does look strange for only one side to have suffered this misengagement. Perhaps the issue lies within the caliper itself, in which case replacement or rebuild are the two options. The rebuild is simple enough and parts are cheap, but there is the chance you could mess up the caliper by reassembling it incorrectly.

Should it come to that, you will need the Helms manual in order to rebuild the rear brake caliper, no exception.

The wear on this pad shows that whoever installed the pad failed to reset the piston on the rear caliper. Having significant play, the pad was able to fall from its groove on the caliper bracket; I would even be curious whether or not you still have both retainers. Once out of the groove and sitting at an angle, the pad was unable to contact the rotor evenly and the uneven wear you see occurred through normal use.

Solution: buy new pads and have your rotors turned, replace the rotors if the thickness is out-of-spec. Reinstall correctly this time: screw the caliper piston in, install the new pads and caliper, and then reset the mechanism as I described before. If you're unable to reset the caliper due to some internal issue with the mechanism itself, defer to my response in your other thread about the parking brake.

Given the condition of the rear set, I would be concerned with the front brakes and what condition they are in, i.e. were they installed properly and if so are the calipers functioning as they should?

[GeoffM]

Look at the big picture, remember my response in your other thread (see below)? This is more evidence that supports the idea that your parking brake was not properly reset after the pads were changed.



The wear on this pad shows that whoever installed the pad failed to reset the piston on the rear caliper. Having significant play, the pad was able to fall from its groove on the caliper bracket; I would even be curious whether or not you still have both retainers. Once out of the groove and sitting at an angle, the pad was unable to contact the rotor evenly and the uneven wear you see occurred through normal use.

Solution: buy new pads and have your rotors turned, replace the rotors if the thickness is out-of-spec. Reinstall correctly this time: screw the caliper piston in, install the new pads and caliper, and then reset the mechanism as I described before. If you're unable to reset the caliper due to some internal issue with the mechanism itself, defer to my response in your other thread about the parking brake.

Given the condition of the rear set, I would be concerned with the front brakes and what condition they are in, i.e. were they installed properly and if so are the calipers functioning as they should?

I installed front and rear pads.
Apparently I didn't install them correctly. At the time I thought it was as simple as replacing the pads, So that's what I did. The right rear: I was trying to screw the piston back in, but accidentally way over extended it. This pad is from that caliper.
I do appreciate you connecting the dots. It helps a lot to have members like you.