Thanks Randall,
I reread Nelson's write up at Buckeye, and it washes with what you said. The
interior walls of the
cylinder don't make much difference because they only hold the seals. It's the
piston side wall that
slides against the seal rather than the other way around as in the master
cylinder or wheel cylinders.
Seems that if that's the case I should be able to bead blast the caliper
cylinders as long as I plug
the brake fluid passages which must be there -- I just don't know where they
are since I've never
had them apart yet.
Nelson acknowledges the official recommendations not to separate the calipers,
but dismisses it --
and rather rudely. He torques the 7/16" bolts to 70# and the 3/8" bolts to 40#.
What is a torque to yield design?
The little O ring is Moss part number 583-820. It is listed for all sorts of
cars and is listed as
the O Ring between caliper halves for the TR250 and TR6. I understand from
6pack posters that TRF
has them also, but not listed in the catalog. I have a bunch of them from Moss.
I hope Nelson is
right and they fit.
Thanks,
Don Malling
Randall wrote:
>>If the pistons are stuck in the calipers doesn't that mean that the
>>caliper cylinders are rusty too.
>
>
> The bore of the caliper is actually unimportant. Unlike all the other
>hydraulic
> cylinders, the sealing surface of the caliper is on the piston, which can be
> replaced separately. And the groove that the seal seats into will likely be
> fine at the bottom, because the brake fluif can't carry water into it.
>
>
>> I never hear anything about how to clean up the caliper cylinders.
>
>
> FWIW, the book says not to disassemble the two halves of the caliper. If you
> do, you're supposed to replace the bolts, as they're reputedly a "torque to
> yield" design; plus there's an O-ring that needs to be replaced but isn't
> available from the usual suspects.
>
> I just knock off any loose rust with steel wool, clean thoroughly with
> brake-friendly solvent, wipe down with DOT 5 & put them back together. DOT 5
>is
> a great preservative, it even preserves rust !
>
> Randall
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