Hi all,

Having changed the discs and pads with Trooper's help on the weekend we noticed some very strange wear on the inside of each front disc. The pads are worn flat and not in a wedge so it isn't due to sticking pistons but they do have a groove that follows that on the disc. The mark on the disc is raised slightly and we couldn't really work out how it could have happened.

I have a couple of ideas but these are just a guess.

It could be possible that the compound of the disc or pad are not even so leading to this wear pattern but this is unlikely due to it happening on both discs and only on the inside of the disc.

My other idea is that maybe the pads were damaged at some point by a mechanic during one of the times the callipers have been removed. Maybe using a screw driver or something against the pads to push the pistons in when putting the calliper back on the disc?????

Other than that, I have no other clues at this point.......

 

I am still struggling with this myself.
My initial thought was a poorly bled caliper but then why on both inner sides on both discs

Perhaps the inner edge of a batch of discs did not get the same or got more heat treatment during manufacture, making it harder than the outer face, hence the wear

I wonder if Ian Godney as seen this before?

 

Very strange.

 

It as been suggested that the inside part of the pins get dirty and corrode, preventing proper pad movement.
The pins were not easy to remove and this would make sense.

 

Possible wheel bearings on way out sticking pads on pins, hub nuts slack , but above all discs look well past sell by date.

 

Discs were indeed toast to be fair and what Ian says about the pins could be a possibility. I would imagine if it werd bearings then the wear would be at the outer edge of the disc and pad creating a wedged pad rather than a groove and the bearings were replaced a while back.........

I guess it isn't important to know, just curious now.

 

Hello - as a lurker and now back in a Subaru, I am curious, too. Were these discs grooved in the first place? If not, were these ventilated front disks ...... and do the beautifully spaced marks line up with the ventilating vanes between the two disc surfaces?

The suspense is killing me!😀

 

The discs were grooved from new and they are ventilated. I am guessing you are thinking the additional cooling in the ventilated area behind the disc has had an effect maybe or do you have something else in mind?????

 

It is a slightly bizarre first post.