Can anyone say whether this method might work to free a rusted piston
and caliper of a classic car? If so any tips to set about it?

AJH

On Sun, 07 Feb 2016 14:46:59 +0000, wrote:

Can anyone say whether this method might work to free a rusted piston
and caliper of a classic car?

It might (I've used it for general de-rusting with reasonable success)
however you might need insure the process can 'see' any areas that are
rusted so maybe not (even if you split the caliper).

If so any tips to set about it?

This might give some good guidance:

http://www.oldengine.org/members/orrin/rustdemo.htm

This link mentions hydrogen embitterment towards the bottom:

http://www.htpaa.org.au/article-electro.php

However, think you might be better (to start with anyway) by soaking
it in something like Plus Gas (or any other good penetrating oil, not
just WD40) and maybe warm it up a few times with a hot air gun and re
applying etc.

If you have tried something other than a penetrating oil or if you
still have hydraulic fluid inside the caliper it might be best to wash
it all out in some light spirit of some sort (panel wipe?) get it dry
and then try the penetrating fluid inside and out.

Do you know where the rusting is? If the dust seal has failed on the
outside it can be between the outside world and the seal or from water
in the brake fluid on the inside and up to the seal.

Then you have to hope that when you do get the piston out that nothing
is too rust damaged. ;-(

Cheers, T i m


p.s. I used an old PC PSU for the 12V. ;-)

On Sun, 07 Feb 2016 14:46:59 +0000, wrote:

Can anyone say whether this method might work to free a rusted piston
and caliper of a classic car? If so any tips to set about it?

I've used it quite a lot. Washing Soda is the electrolyte to use
(Sodium Carbonate) and for electrodes I used lengths of reinforcing
bar.

http://remaponline.org.uk/remapedia/...ic-de-rusting/

If the parts are entirely iron/steel it has the advantage that it is
quite difficult to harm what you are de-rusting (which is why
archeologists like it). If there are alloy components that may not be
true.

It takes a long time, typically days, but you won't harm anything
leaving it for too long.

If you are concerned about Hydrogen embrittlement bake the part for
about 8 hours at 190deg C (Domestic oven temperature - but wait until
SWMBO is away). This bake should be done as soon as possible after
removing the part from the cleaning bath, rinsing it off and coating
it with a very thin layer (wiped on with a rag) of oil. I've never
found it to be an issue except possibly with things like chisels as
the parts you are cleaning have already corroded (Otherwise you
wouldn't be cleaning them like this) and are already somewhat
compromised.

On 07/02/2016 14:46, wrote:
Can anyone say whether this method might work to free a rusted piston
and caliper of a classic car? If so any tips to set about it?

AJH

What sort of car is it? Have you checked on the availability of spares
via enthusiasts' clubs, breakers yards, etc.?
--
Cheers,
Roger
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Please reply to Newsgroup. Whilst email address is valid, it is seldom
checked.

On 07/02/2016 16:56, Roger Mills wrote:
On 07/02/2016 14:46, wrote:
Can anyone say whether this method might work to free a rusted piston
and caliper of a classic car? If so any tips to set about it?

AJH

What sort of car is it? Have you checked on the availability of spares
via enthusiasts' clubs, breakers yards, etc.?

Where I used to work, we used to use a company oop North that
re-machined old calipers, inserting sleeves etc where necessary. Not
cheap, but sometimes the only realistic option when something was NLA
and nothing modern could be made to fit.
Probably not much help that I can't recall the name of the company

Lee wrote:
On 07/02/2016 16:56, Roger Mills wrote:
On 07/02/2016 14:46, wrote:
Can anyone say whether this method might work to free a rusted piston
and caliper of a classic car? If so any tips to set about it?

AJH

What sort of car is it? Have you checked on the availability of spares
via enthusiasts' clubs, breakers yards, etc.?

Where I used to work, we used to use a company oop North that
re-machined old calipers, inserting sleeves etc where necessary. Not
cheap, but sometimes the only realistic option when something was NLA
and nothing modern could be made to fit.
Probably not much help that I can't recall the name of the company

I recall a thread on this newsgroup some years ago which gave a
reference/link to derusting drum brakes. I have lost the link, but
maybe someone else has it?

On Sun, 07 Feb 2016 16:56:48 +0000, Roger Mills
wrote:

On 07/02/2016 14:46, wrote:
Can anyone say whether this method might work to free a rusted piston
and caliper of a classic car? If so any tips to set about it?

AJH

What sort of car is it? Have you checked on the availability of spares
via enthusiasts' clubs, breakers yards, etc.?

It's my mate's mini cooper s

We're soaking it in diesel first and then will try to hydraulic it out
with a grease gun.

The I'll see if he will let me use the electrolysis, thanks for the
pointers Tim and Peter.

I have advised against splitting it for now.

AJH

On 07/02/2016 20:55, wrote:
On Sun, 07 Feb 2016 16:56:48 +0000, Roger Mills
wrote:

On 07/02/2016 14:46, wrote:
Can anyone say whether this method might work to free a rusted piston
and caliper of a classic car? If so any tips to set about it?

AJH

What sort of car is it? Have you checked on the availability of spares
via enthusiasts' clubs, breakers yards, etc.?

It's my mate's mini cooper s

We're soaking it in diesel first and then will try to hydraulic it out
with a grease gun.

The I'll see if he will let me use the electrolysis, thanks for the
pointers Tim and Peter.

I have advised against splitting it for now.

AJH

Critical safety part. Buy a new one (pair preferably). If "originality"
concerns you - put them in the boot when you sell it one so that
somebody else can clean them up ans refit the originals.


--
Blow my nose to email me

On Tuesday, 9 February 2016 09:16:41 UTC, Kellerman wrote:
On 07/02/2016 20:55, wrote:
On Sun, 07 Feb 2016 16:56:48 +0000, Roger Mills
wrote:

On 07/02/2016 14:46, wrote:
Can anyone say whether this method might work to free a rusted piston
and caliper of a classic car? If so any tips to set about it?

AJH

What sort of car is it? Have you checked on the availability of spares
via enthusiasts' clubs, breakers yards, etc.?

It's my mate's mini cooper s

We're soaking it in diesel first and then will try to hydraulic it out
with a grease gun.

The I'll see if he will let me use the electrolysis, thanks for the
pointers Tim and Peter.

I have advised against splitting it for now.

Critical safety part. Buy a new one (pair preferably).

that's no reason to discourage someone capable of the job

If "originality"
concerns you - put them in the boot when you sell it one so that
somebody else can clean them up ans refit the originals.


NT

In article ,
wrote:
Critical safety part. Buy a new one (pair preferably).

that's no reason to discourage someone capable of the job

No - but if it's so rusty the piston won't shift, the bore in the caliper
will be pitted or damaged in some way. The piston can be replaced, but the
only fix for a pitted bore is to sleeve it. And given the low cost of a
new caliper, not worth it.

Typically, a complete new caliper costs about 2-3 times the price of new
pistons.

--
*I have my own little world - but it's OK...they know me here*

Dave Plowman London SW
To e-mail, change noise into sound.

In article ,
wrote:
Can anyone say whether this method might work to free a rusted piston
and caliper of a classic car? If so any tips to set about it?

What make of caliper? Most are still available. And if the caliper bore is
rusted, it's likely scrap, or will need sleeving.

--
*Why isn't there a special name for the back of your knee?

Dave Plowman London SW
To e-mail, change noise into sound.