Plating Callipers

[JJ66]

Zinc plating is only really applied 'line of sight' between the anode / cathode, so it won't get into holes etc. I've had 4 sets done and my mate does all the zinc plating at the company he works for. Always given them to him bare and separated. If any does get onto the mating face I just stone it off slightly. It doesn't have anything to do with the seal, that's what the o ring is for. Piston bores don't really take any plating due to being out of line of sight, but again, I don't think it would matter as it's the seals that do the work. I think zinc plating is about 1/4 of a thou, so negligible. I doubt girling calipers were even made to that tolerance 60 years ago.

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Hi There, Just for interest, the tolerance of the piston that goes into the caliper half is 22 ten thousandths", or 2.2 thousandths of an inch. The diameter of the T16 piston was 2.1252/2.1230" (53.980/53.925mm). I don't have the exact bore size of the housing to hand, but if I find it I'll let you know, just for interest

Regards, Jonathan