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]
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.
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.
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.
A new pair of discs on ebay for around £20-30 might also be a "cheap" option....
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!
Wire brush
Phil
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.
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.
drive, brakes on, nice and clean
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
Personally I would just use them as is unless there's serious pitting. They will clean up after only a few hard stops.
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.
quote:
Originally posted by Confused but excited.
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.
quote:
Originally posted by Confused but excited.
Since when does one paint discs?
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
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]
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