Paul TigerB6
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| posted on 27/12/07 at 04:42 PM |
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De-rusting brake disks
Hi all,
Whats the best way to de-rust a set of brake disks?? They have been left on a part built car that i am building up for someone to go rusty. They were
brand new (at least 3 years ago!!) so am hoping they can be saved.
Electrolysis or wire brush with wet n dry on the machined braking surface??
[Edited on 27/12/07 by Paul TigerB6]
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David Jenkins
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| posted on 27/12/07 at 04:58 PM |
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I'd guess that it depends on the level of rusting...
If it's just a dusting, then wet-and-dry would do the job.
If there's pitting, then I would trust only a skim on a lathe, done by someone who knows what he's doing.
But that's just my opinion - others with more experience may have other views! 
Whatever you do, make sure that you end up de-greasing with some brake cleaner.
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RazMan
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| posted on 27/12/07 at 05:03 PM |
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Ideally electrolysis but this can be a pain to set up just for a pair of discs. It will remove every scrap of rust though.
Alternatively one of the rust removal gels that Halfrauds sell will do the trick - in either case remember to prime and paint afterwards.
Cheers,
Raz
When thinking outside the box doesn't work any more, it's time to build a new box
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Paul TigerB6
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| posted on 27/12/07 at 05:08 PM |
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Excellent thanks guys. I'll set up the electrolysis then and do all my own donor parts while i am at it - just wasnt too sure if electrolysis
would damage the machined surface at all. If the disks are pitted then they will just have to be skimmed or replaced dependant on cost.
I will need to do the flywheel too thinking about it.
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nitram38
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| posted on 27/12/07 at 05:20 PM |
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A new pair of discs on ebay for around £20-30 might also be a "cheap" option....
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trextr7monkey
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| posted on 27/12/07 at 05:41 PM |
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very Locost technique:
Overnight in a bucket of Tesco vinegar will remove surface rust (but not pitting) and there's change from a pound too!
http://www.flickr.com/photos/14016102@N00/ (cut and paste this dodgey link)
Our most recent pics are here:
http://s129.photobucket.com/albums/p211/trextr7monkey/
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Hellfire
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| posted on 27/12/07 at 05:53 PM |
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Wire brush
Phil
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wilkingj
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| posted on 27/12/07 at 06:09 PM |
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IMHO They are Safety Related Mission Critical parts.
Ditch them and fit new ones, Unless it really is just a minor surface dusting.
Think of your (and others) safety before your wallet.
1. The point of a journey is not to arrive.
2. Never take life seriously. Nobody gets out alive anyway.
Best Regards
Geoff
http://www.v8viento.co.uk
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David Jenkins
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| posted on 27/12/07 at 06:39 PM |
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Absolutely correct - when I say 'skim' than means 'within the limits laid down in the spec' - a new set of disks is by far the
safest option! Not particularly expensive either.
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blakep82
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| posted on 27/12/07 at 06:42 PM |
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drive, brakes on, nice and clean
________________________
IVA manual link http://www.businesslink.gov.uk/bdotg/action/detail?type=RESOURCES&itemId=1081997083
don't write OT on a new thread title, you're creating the topic, everything you write is very much ON topic!
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Cousin Cleotis
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| posted on 27/12/07 at 07:08 PM |
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A quick blast with a twist knot brush and a quick polish with 180grit wet and dry. The brake pads will do the rest, drive no different to bedding in
new pads.
If there is too much rust and you use the brake pads to clean it off it can sometimes glaze over.
Paul
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matt_claydon
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| posted on 27/12/07 at 08:13 PM |
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Personally I would just use them as is unless there's serious pitting. They will clean up after only a few hard stops.
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Confused but excited.
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| posted on 27/12/07 at 09:14 PM |
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quote:
Originally posted by RazMan
Ideally electrolysis but this can be a pain to set up just for a pair of discs. It will remove every scrap of rust though.
Alternatively one of the rust removal gels that Halfrauds sell will do the trick - in either case remember to prime and paint afterwards.
Since when does one paint discs? 
Tell them about the bent treacle edges!
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Paul TigerB6
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| posted on 27/12/07 at 09:25 PM |
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quote:
Originally posted by Confused but excited.
Since when does one paint discs?
Cheers all. I will have a look at them tomorrow and see how much rust there actually is. If they are in any way pitted then they will be replaced -
skimming just isnt worthwhile. The bloke i am building the car for is on a pretty tight budget and was actually on the verge of selling the car at a
huge loss. I wont risk his safety though.
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iank
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| posted on 27/12/07 at 09:48 PM |
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I, personally, wouldn't use electrolysis on discs. There seems (from a non professional chemist's viewpoint) that there may be a
risk of hydrogen embrittlement. If there is any possible chance of critical components getting brittle I will tend to choose another method for
those.
For the price of a new pair I'd probably go for those anyway.
Some people (not me) do paint the bells and edges of their discs (not the braking surface obviously), I suppose it's the kind of thing that
could spoil an otherwise shiny car for a judge.
--
Never argue with an idiot. They drag you down to their level, then beat you with experience.
Anonymous
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RazMan
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| posted on 27/12/07 at 11:24 PM |
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quote:
Originally posted by Confused but excited.
Since when does one paint discs?
The non-shiney bits of course - I paint everything that isn't a friction surface to prevent rusting 
Cheers,
Raz
When thinking outside the box doesn't work any more, it's time to build a new box
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Hellfire
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| posted on 28/12/07 at 12:38 PM |
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quote:
Originally posted by RazMan
quote:
Originally posted by Confused but excited.
Since when does one paint discs?
The non-shiney bits of course - I paint everything that isn't a friction surface to prevent rusting
Ditto........
Phil
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britishtrident
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| posted on 28/12/07 at 04:19 PM |
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First of all they must be cleaned up before running or the disc will end up a mess and the pads contaminated.
Wet and dry won't look at it
Best way to rust off can be by electrolysis, acid cleaned (acetic (vinegar) or phosphoric (naval jelly)) neither of which will remove good metal.
Using and electric drill or grinder with Wire brushs or paint sripping pad works pretty well.
As long as the disc's surface isn't badly pitted the pads will bed in fine. However ideally to bed the pads in you need a slightly keyed
surface so it is best to lightly scratch up the surface of the discs with production paper or coarse emery immediately before the first use.
[Edited on 28/12/07 by britishtrident]
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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britishtrident
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| posted on 28/12/07 at 04:25 PM |
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quote:
Originally posted by Hellfire
quote:
Originally posted by RazMan
quote:
Originally posted by Confused but excited.
Since when does one paint discs?
The non-shiney bits of course - I paint everything that isn't a friction surface to prevent rusting
Ditto........
Phil
When laying cars up over the winter the very lightest mist coat of zinc primer is a good idea much easier to remove than rust after the winter
layup.
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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