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Goggomobile
12th Oct 2015, 07:54 AM
Hi all

Ive pulled all of the brakes down. Parts are available ex Europe but I'd have to sell my left lung to afford.

Any tips on removing the Pistons. I will get the cylinders resleeved. Hoping to salvage the Pistons.

Randal

droog
12th Oct 2015, 08:05 AM
I have seen caliper pistons removed using a grease gun, maybe worth a try ?

YBAF
12th Oct 2015, 11:19 AM
Save the pistons! Good excuse to fire up the lathe I woulda thought :cool:

KBs PensNmore
12th Oct 2015, 02:09 PM
Hi Randal,
If the grease gun trick doesn't work the only other option is to press them out. Close the bleeder valve, locking in any grease, and set it up over a piece of metal with a hole a mm or so larger than the piston, and then go to town with the press, I think using a hammer and punch would be a pointless exercise as the press would keep up pressure on the piston. I can't remember if I mentioned here or elsewhere that for a vehicle of limited use, to get the cylinders lined in stainless steel and use a synthetic brake fluid as it does'n attract moisture. PBR should be able to do that job easily. This was told to me by a couple of friends who have restored several Suzuki LJ50s.
Regards
Kryn

jhovel
12th Oct 2015, 02:15 PM
Before you force the piston out y whatever means - if indeed force is required, make sure to crack the corrosion between the cylinder and piston first. Remove as much corrosion as posible too. Otherwise you are sure to score the piston.
Give the whole thing a good soak inside and out in firstly degreaser, then rust converter, then penetrating oil, cleaning off everything that loosens andn that you can reach.
Then you can try moving the pistons with a mastercylinder (any, including a conveniently mounter motorcycle front brake one). Most likely, one of them will move first. Allow it to move a bit, but not past the seal. THen clamp it in place somehow so that all the force from then on goes to the other piston. Once it moves, pop it out. You can then push the clamped one out from the inside with a soft drift and hammer.
If brake fluid won't move them, a grease gun fitted to the wheel cylinder with an adapter will provide much more force and may work. Try to get as much grease into the cylinder before connecting, to replace the air in it. Compressing air to 10000PSI is one hell of a spring and may launch the first piston over the fence :(
If that fails, heat may be you friend. Not just too hot to handle, but actually discolouring hot. It will bugger up the seals and you should really try and get the pistons out then, so the seals don't melt and run into any corrosion, relly making the pistons stuck.

Last resort: press both piston out in the same direction in a press. The wheel cylinder is almost certainly a straight through bore.
Good luck and let us know how you go - with photos.

Edit: droog and Kryn beat me to it whlle I was typing.....

Goggomobile
13th Oct 2015, 07:53 AM
Thanks guys. I would have never thought of the grease approach. I'll keep you posted. The 10000 psi idea did interest me as I've got some noisy sheep that need a blast ��

KBs PensNmore
13th Oct 2015, 12:42 PM
Randal, thanks for breaking up the sections, brakes, fibreglass etc, as that way, anyone looking for information on a particular subject, doesn't have to scroll through heaps of postings before they find an answer.:2tsup: Yes I know they could use the search button, but what if they are like me, don't like it.
Kryn

Goggomobile
26th Oct 2015, 09:50 PM
Good news all out ... Bad news very rusty and scored ... I've found a brake guy who will re sleeve and re shoe .. . Much cheaper .. I think he was a Farrier in a past life ... ��