On or around Fri, 13 Aug 2004 09:09:49 +1200, EMB <
[email protected]>
enlightened us thusly:
>M0bcg wrote:
>
>> if you get some emery cloth and rub around end of piston thats sticking out of
>> caliper , then put some copper slip compound wipred around lightly .
>
>*DON'T* do this. Copper slip is oil based and will destroy the caliper
>seal. Use a proper rubber grease (like Girling Red Rubber Grease) that
>is vegetable based.
the other point to make here is that on most calipers, the seal is in the
cylinder, not the piston, and if the piston surface is damaged, it's more
likely to leak. You can, it's true, clean 'em up, but if the hard chrome
surface is pitted, expect the seals to fail.
Of course, I'm talking about the part of the piston which actually comes
into contact with the seal, here. The seal, obviously, is inside the
cylinder, and the bit of piston which is poking out the end can be as rough
as you like. Trouble is, you have to push them back nearly flush to fit new
pads, and the chances are that if more than the top few mm of the piston is
iffy, then the damaged bit will now be working in the seal, and will cause
it to fail in due course.
you can get pistons, but they're not that cheap when I asked about 'em.
However, you'd be unlucky to have to replace all 8 on a RR/disco front, and
I see no objection to replacing just the ones that are damaged.
If they're only covered in crap, and not rusty, clean 'em off with something
non-abrasive.
--
Austin Shackles.
www.ddol-las.fsnet.co.uk my opinions are just that
"Nessun maggior dolore che ricordarsi del tempo felice nella miseria"
- Dante Alighieri (1265 - 1321) from Divina Commedia 'Inferno'