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Brake Disc Skimmimng

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Normski View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Normski Quote  Post ReplyReply Direct Link To This Post Posted: 09 Jun 2019 at 09:31
They are cast for big block Tonti, T3-SP etc, two I need doing were in fact brand new but showed a wear pattern which looked similar to a dart board (the pattern followed the oval holes in the disc) with very little use, seems they were got too hot when machined during manufacture? After a lot of going and froing with the supplying dealer we agreed to me keeping them at a discount. Not too keen to buy new again😎
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Post Options Post Options   Thanks (0) Thanks(0)   Quote c13pep Quote  Post ReplyReply Direct Link To This Post Posted: 09 Jun 2019 at 11:24
Modern discs have the minimum thickness stamped on them but it`s only a guide as different vehicle manufacturers have their own limits. The likes of Mercedes, BMW etc. use mileage and time to replace discs whatever their condition.
At my local MOT station he told me of a Mercedes C class that had passed its test with no problems but was returned 3 weeks later after the owner asked for a second opinion after the main dealer said that all discs and pads needed replacing! The MOT tester confirmed that all discs and pads were in good serviceable condition and well within limits. He contacted the dealer only to be told that it was a Mercedes service item because of the mileage covered. So this `gentle` elderly driver was classed the same as a `hard` braker       

CHRIS
you can`t have any fun in a straight line

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Brian UK View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Brian UK Quote  Post ReplyReply Direct Link To This Post Posted: 09 Jun 2019 at 12:17
That's just the car manufacturer and dealer covering themselves, and making money of course.
Brian.

Better 5 minutes late in this world than years early in the next.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote c13pep Quote  Post ReplyReply Direct Link To This Post Posted: 09 Jun 2019 at 13:23
The dealer inferred that the MOT was not right and that it was a safety issue, apart from the over £1000 quotation

CHRIS
you can`t have any fun in a straight line

Monza project
BMW R1150RT
1200 Sport project
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red leader one View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote red leader one Quote  Post ReplyReply Direct Link To This Post Posted: 09 Jun 2019 at 20:07
I don't think I'll be buying my S Class now knowing that.
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c13pep View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote c13pep Quote  Post ReplyReply Direct Link To This Post Posted: 09 Jun 2019 at 21:15
Originally posted by red leader one red leader one wrote:

I don't think I'll be buying my S Class now knowing that.


I didn`t think a man of your calibre would want to trade down anyway

CHRIS
you can`t have any fun in a straight line

Monza project
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GUZZIPETE View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote GUZZIPETE Quote  Post ReplyReply Direct Link To This Post Posted: 11 Jun 2019 at 22:25
Cast iron discs from the earlier bikes skim on the lathe quite readily. 

Stainless discs are a different matter, and a lot would depend on the grade of stainless. But I suspect grinding would be preferable, if not crucial. I have not tried it.

On the cast discs, if there is enough thickness left to be able to take a 'minimum-to-clean' amount off without going undersize, which could be as little as say 5-10 thou, it can be a simple task and worth doing if they have become 'furrowed' over time, especially when fitting some new pads. I have skimmed a couple on my bikes over the last few years without issue. Unfortunately the lathe won't quite take a 300mm disc though.

I've found that skimming new brake shoes whilst on the carrier is also beneficial, and gives a much larger contact area on the drum. Again, it doesn't need a lot to take off. 
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