I have just one comment about this -- it is based on my (possibly incorrect)
assumption that a standard "US made" grease gun uses a 1/8NPT fitting on the
end. If anyone (Karl specifically) can point me at a brake line fitting (on
any reasonably modern car for that matter, not just british) with NPT
threads, I'd sure like to see it. I'm not saying the method described below
will not work to free the pistons. I'm just saying that cross-threading
parts onto a brake line might not be the best thing for the future of that
brake part. If you can find a fitting for you grease gun to *properly*
thread onto a brake line, go ahead. Otherwise I would not do it (cross
thread a fitting onto a brake line). JMO of course, not trying to be
alarmist or anything.
Check out <http://www.dimebank.com/BrakePlumbing.html> for a some good info
on brake lines.
Peter Zaborski CF58310UO
> -----Original Message-----
> From: Karl Vacek [mailto:KVacek@Ameritech.net]
> Sent: January 10, 2000 6:15 AM
> To: TR Listserv
> Subject: Removing stuck caliper pistons the safe and effective way
>
>
>
> Missed this one yesterday, but in scanning the replies, I only noticed
> various prying and air-pressure options recommended. Prying
> can easily
> damage parts, and maybe you. Air pressure can make a piston
> into a missile,
> or at least smash a finger or two if/when the piston pops
> loose. Besides,
> the pressure available with air is pretty small compared to
> typical brake
> system pressures, and it may not be enough There's a good
> and SAFE way to
> remove stuck pistons.
>
> Disconnect the brake hose from the steel brake line at the
> chassis bracket,
> and take the caliper off, with the hose still in the caliper. Run the
> locknut down the threads all the way onto the brake hose.
> Get a grease gun
> (full of cheap grease) and unscrew whatever outlet fitting is
> threaded into
> it. Match the threads of the hose and grease gun - if it's a
> US-made grease
> gun they SHOULD match, but if you don't have a US-made grease
> gun, maybe
> not. When you have a matching grease gun, thread the brake
> hose into the
> grease gun and begin pumping grease into the caliper. Soon
> you will see one
> or both pistons moving. Just before the first one pops out,
> stop it from
> moving farther with a "C"-clamp, and continue pumping grease
> till the other
> piston gets to the same point, then carefully remove both
> pistons - they
> should by now easily slip out by hand.
>
> This method has the advantage of being more powerful (many
> hundreds to well
> over 1,000 PSI of pressure available from most grease guns) and safe -
> grease is essentially non-compressible, so when you stop
> pumping, there's no
> accumulated pressure - nothing will explode.
>
> Karl Vacek
> '66 TR4A - IRS
> '64 Amphicar
> '16 Ford T Touring
> '46 Piper J-3 Cub
>
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