[Healeys] Aluminum brake & clutch cylinders

[Andy Thorp]

The few times I have worked with hard anodised aluminium tells me that the
cylinders are definitely not hard anodised and almost certainly not
decoratively anodised either. I'm gonna call myth on this one.

Hard anodising is so hard that it sparks dull red if you scratch it which
gives off a distinctive smell, not the same as but not unlike striking a
match. Hard anodising is also about 2 thou thick, reasonably porous and
usually dull brown-grey.

Decorative anodising also sparks if you scratch it just right although the
coating is much thinner so harder to achieve. There is a distinctive hissing
sound to scratching anodised ali, try it next time you are at a car show on
some cockpit surrounds. I have never seen any wheel or master cylinder that
could be scratched in this way, they were all bare ali inside including the
brand new Girling master cylinder I just tested.

Instead of fitting poorly made copy parts or risking bodgered up old ones, why
not get stainless steel sleeves fitted and be done with it. They cost about
$30 or so each to have fitted down this part of the world.

Andy.


--------------------------------------------
On Thu, 6/3/14, WILLIAM B LAWRENCE <ynotink at msn.com> wrote:

 Subject: Re: [Healeys] Aluminum brake & clutch cylinders
 To: warthodson at aol.com, coudesluijs at chello.nl, healeys at autox.team.net
 Received: Thursday, 6 March, 2014, 2:32 PM

 I don't know where the "assertion"
 comes from either, but I believe it. No one
 claims that the entire cylinder is anodized, only that the
 Bores are hard
 anodized to make them smoother and less prone to corrosion.
 I'm running wheel
 and master cylinders from my 1959 BN4 on my  BN1.

 I figured out early that the alloy cylinders are not prone
 to wear or
 corrosion unless they are exposed to an electrolytic
 environment. Even through
 many years and many miles the original cylinders showed no
 wear and the only
 problem I found with them was a build-up of solids from
 expired brake fluid. I
 cleaned them up with hot water and dish soap. For the
 tougher spots I used
 some soft scrub. I took care not to disturb the original
 surface and it was
 undamaged even as old as they were. After eleven years of
 use I have never had
 a leak or a failure and my brake fluid is clean.

 I think that if a cylinder is damaged to the point that it
 needs to be honed,
 a rare occurrence, it should be replaced. If you can't find
 a replacement you
 should have it sleeved. I think there are services that can
 do it in brass or
 stainless steel. Honing the cylinder exposes the raw
 aluminum which corrodes
 and contaminates the brake fluid. I doubt if polishing the
 bore will have much
 effect.

 My 2 cents...