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MG MGA - MGA disk calipers - center pin

I'm in the process of restoring the seals in my MGA disk calipers and I have a problem getting the pistons back into the cylinder. The piston gets stuck and will not go down into the cylinder. At first I thought I had installed the fluid seal incorrectly. I pulled the seal out, however, and just tried to set the piston back in. It seems to be getting hung up on the center pin. Without the fluid seal, the piston has clearance on the bore and can rotate and wobble. If I push the piston in, however, the center pin holds it tight. The pin itself is clean and smooth but maybe there's some rust or something in the hole that receives the pin? Anyone else had a problem like this? Unless I can figure out the issue, I'm considering pulling out the center pin or cutting it off like others have done to fit MGB pistons in the caliper.
R Lewis

I don't know about the pushrod MGA, but with the Dunlop brakes on the mga twin cam the pin passes into a bush which looks a bit like a coil spring.
The pin is quite a tight fit in the bush.
Most people have discarded those pins long ago.


Mick


M F Anderson

M.Lewis,

I have done this 20 years ago with my calipers , i have removed the center pin with a wise-grip and a hammer and fit MGB's pistons in place .

Easier to fit and less expensive to buy . I have no problems with the pistons since .

Good luck .

Jules .
MGA 1600MKII

jdesb@videotron.ca

Jules Desbiens

The MGA 1600 Workshop Manual also shows the bush that tightly fits on the pin. It is item 5, the friction stop.
A useless design feature.


Mick


M F Anderson

Given the feedback, I think I'm going to dig out the vice grips and hammer. Anything I should be cautious about in trying to pull out the center pin? Would some penetrating oil help?
R Lewis

This thread was discussed between 17/01/2010 and 18/01/2010

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This thread is from the archive. The Live MG MGA BBS is active now.