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Up Topic C1 Information / Repairs - Faults & Fixes / Rear caliper
- - By p.gill Date 01.09.20 16:57 Edited 01.09.20 17:02
Hi C1ers
Several months ago I replaced the rear disc and pads, all went well no problems, just had a look at the inside of the rear disc and only half of the disc is being swept.  Looking at the calliper from the the back of the bike the inner pad was lying at an angle, first thought the calliper had got deformed/bent!
Upon comparing it with a spare the two lugs had worn, the wear was tapered to about 2/3mm, as the photo shows.
Am contemplating what’s the best repair!
Anyone else come across this issue?
Paul
Attachment: A91BE19F-E5AB-4953-9C33-8A1902F0AF05.jpeg - Rear disc (77k)
Attachment: 46B477E6-3288-4BB4-9DF1-37598C18FC37.jpeg - Comparing the lugs of two rear callipers (110k)
Parent - By rockstedy Date 01.09.20 21:06
Came with similar problem- less visible than in your case. After replacing brake disc and pads noticed that wear isn’t equal as should be and is less towards disc centre. Going to examine closely ( check if not bend- most likely wear) when finish rebuilding front of bike but planing  to replace whole rear alloy bearing holder+nearly new complete calliper unit and see what future use brings. Did use graphite grease on pins for many years but should be silicone- not sure if that could contribute to the problem.
Parent - - By alunt Date 02.09.20 08:36
Hi Paul
I remember reading about this kind of uneven pad wear being a problem many years ago. Some of it was due to the pad retaining pin holes wearing, but maybe the wear you've seen was also a problem. I think Lawrie made up some bushes to insert in the calipers, once the holes had been drilled round again. Maybe a search will reveal something. Don't forget to spell caliper with one L though!
Parent - By rockstedy Date 04.09.20 19:56
There must be a problem with pin hole wear  as there was  kit with metal insert available in C1 German shop. Unfortunately since early 2020 shop closed for good.
Parent - By p.gill Date 05.09.20 19:07
Hi Andrew
When you do a search with one L or two Ls, it’s about 50/50, I’m sure your right and my spell checker is wrong in this context!
Paul
Parent - - By variobob Date 04.09.20 21:03
Hi Paul,

What happens a lot, is that the brake pads digg into the stainless inlay (and eventualy into the aluminium) of the caliper itself. As the pads do this, the free horizontal movement is from a certain point on no longer possibel. This is when the caliper itself start wearing unevenly. In the end the inner pad is no longer working in a vertical position. instead it tilts a bit. Once this process has started it is inreverseble.  As long as you leave the old brake pads in, it will function reasonably well as the pads develop a certain angle along with the caliper. New once though are evenly thick. If they are mounted in a 'worn' caliper (with an angle unequal to 90 degree) the inner pad will only 'bite' partialy.

There are a few options: find an alternative for the black caliper itself (if from a honda CB500S the chances of receiving a good one are close to 100%). One problem will last: the original caliper has probably damaged the aluminium plate with the rear wheel bearings in it. One of the sliding holes has become to large (diametricly) which causes to much play, also when the caliper itself is changed. Best option? Renewal. On the downside of this option: expensive and the retaining pin is a screwed one.

Good luck with your brake!

Bob
Parent - - By p.gill Date 05.09.20 19:13
Hi Bob
Thanks for your explanation, as always informative.  Am endeavouring to over come this wear with an engineering solution, awaiting materials to arrive, will keep you informed as progress is made!
Paul
Parent - - By p.gill Date 01.10.20 09:53
Hi
Have finished the repair to the caliper to bring the two faces back parallel.
Parent - By patc50 Date 01.10.20 11:11
Hi Paul - looks like a great job ....... wish I had your engineering skills!

Pat
Parent - - By variobob Date 15.10.20 09:09
I take my hat off for this job. Well done Paul! Are you testing it at the moment? Could you please let us know if any differences occur?

Thanks,

Bob
Parent - - By p.gill Date 16.10.20 16:08
Will report when fitted, as an aside my current project is the restoration of a set of MG A carburettors, to include full polishing and remanufacture of all the fasteners & pins in stainless steel.
Parent - - By variobob Date 19.10.20 18:39
Take your time... you are doing a wonderful job!
Parent - - By p.gill Date 12.11.20 18:28
Just finished!
Parent - By patc50 Date 13.11.20 09:34
Superb engineering Paul - a quality job as always.
Parent - By Gerard Date 13.11.20 17:58
Hi Paul

they look like works of art.

Beautiful job.
Up Topic C1 Information / Repairs - Faults & Fixes / Rear caliper

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