Uneven brake pad wear

[GrumpyGuts]

I made a thread not long ago about my shitty rear brake and this picture may just point to something I mentioned before...

https://i48.tinypic.com/23uygyr.jpg

I swear to god that the disc is warped, surely it's not meant to look like that? It should also explain the very loud groaning noise the bike makes when you move it backwards!

Anybody got any ideas on this? The bike passed the MOT with no advisories so I'm shocked it passed...plus these pads are brand new!

Help appreciated...
____________________
My Bikes: Lifan Beat 125cc '11 -> Suzuki B120P '76 -> Suzuki EN 125-2A '08 -> Honda CG 125 '04 -> Honda CB600F Hornet '98 -> Kawasaki ZZR 600 '99 -> Kawasaki GPZ 500S '95 (Current)
Theory test passed - 09/02/2012 >>>> Module 1 passed 24/07/2012 >>>> Module 2 passed 24/10/2012

[Islander]

Is the caliper sliding freely on its pins? Are both pistons moving freely?

[el_oso]

you are bound to get slightly uneven wear, especially if you are riding this time of year. The cold weather and road salt tends to seize everything.
I would be taking the callipers apart and giving them a very good scrub. If the pistons haven't been popped out and the groves cleaned for a few years then it would be doing a full strip down and rebuild.
If the pads are brand new like you said, you should be able to hear the pads dragging on disk.
____________________
Duke 390
Previous: '05 XR125L | '96 XJ600S Diversion |'05 Suzuki GSXR1000 | '05 Honda CBR125-R | '97 YZF 600R Thundercat | '11 Honda CBR250
Car: Jeep Wrangler 4.0L

[GrumpyGuts]

1) I think so

2) It's only one piston. The caliper was overhauled with new seals etc etc so it is not sticking. However, this picture seems to show that the pad is resting on one side more than the other...

https://i47.tinypic.com/2lwq0jr.jpg

You'll only notice it if you look really closely!
____________________
My Bikes: Lifan Beat 125cc '11 -> Suzuki B120P '76 -> Suzuki EN 125-2A '08 -> Honda CG 125 '04 -> Honda CB600F Hornet '98 -> Kawasaki ZZR 600 '99 -> Kawasaki GPZ 500S '95 (Current)
Theory test passed - 09/02/2012 >>>> Module 1 passed 24/07/2012 >>>> Module 2 passed 24/10/2012

[Islander]

Also check that the pad itself is able to move freely within the caliper.

[Timmeh]

^ that.

Looks like the pad's backing plate is twisting inside the caliper, although the perspective of the picture may be misleading.
____________________
GSXR400 x2 | '94 RVF400 | '93 TZR125 4DL (again)
20:22:30 BLUEX5: i would love to be forced to undergo a**l plugging with different sizes
20:48:18 Temeluchus: comp you hunk of smouldering homos3x you

[GrumpyGuts]

Well I am going to take the rear caliper off AGAIN to clean the slider pin and re-grease it, and a replacement pad pin as it seems the old one is pitted.

However, when I sent the bike to the garage asking them to sort a few things out before the MOT, I did mention the rear brake drag. They discovered it was missing the shims, so they put small pins where the front of the pad body rests in the bracket.

When looking at the Haynes manual and the Honda diagrams, the shim that I was thinking belong to the back of the pad (as a metal place) along with an insulating pad sandwiched in between. These two parts are absent from my caliper....

So I've ordered new pads with the shims and insulating pads on them and I'll report back.

Cheers!
____________________
My Bikes: Lifan Beat 125cc '11 -> Suzuki B120P '76 -> Suzuki EN 125-2A '08 -> Honda CG 125 '04 -> Honda CB600F Hornet '98 -> Kawasaki ZZR 600 '99 -> Kawasaki GPZ 500S '95 (Current)
Theory test passed - 09/02/2012 >>>> Module 1 passed 24/07/2012 >>>> Module 2 passed 24/10/2012

[Fizzer Thou]

Those pads are held in place by the pin at one end of the pad and rest on a chrome shoe at the other end. The shoe often gets corrosion buildup behind it which can force the pad to be forced against the pin and go askew in the caliper.
The other problem that may occur is that a pattern pad backplate is not always exactly the same as the OEM pad and paint on the pad backplate can cause the pad to not move freely on the chrome shoe.It is a good idea to dress down that part of the backplate that sits in the shoe and put a smear of copaslip grease there.
____________________
Just talk bikes.What else is there?

Always have a 'Plan B'

[DrDonnyBrago]

Haven't read the replies but in the first pic as it is the piston side of the caliper, it looks like the pad isn't moving on the pad pin freely. If the pin is notched, it might not slide back properly, get stuck and do that.

Alternatively, could be sticking on the metal clip on the other end, and not moving when pressed by the caliper so only one part is making contact. This seems perhaps less likely.

I'd clean out the caliper, grease the moving parts and replace the pin.