Brake Caliper Piston Bore/Diameter?

JDG

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#1
Does anybody know the Fiesta ST front brake caliper piston diameter? Hoping somebody either knows or has an old caliper on the shelf that can measure it for me. Thanks in advance!
 


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#2
I'm measuring the inner diameter at 45mm and outer diameter at 53.5mm for the edge of the front caliper piston.

That's with the piston still in the caliper. I don't have a rebuild kit on hand at the moment, but I can try to disassemble these old calipers if you need more measurements.

EDIT: the bore diameter is around 57.5mm ish. I can't get a good measurement of that with the caliper still assembled.

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JDG

JDG

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Thread Starter #3
OK, from a ton of searching, it seemed like the piston diameter was 54mm - so your measurements are inline with what I was finding but I couldn't find anything concrete for a MK7.

Thanks so much for taking the time to check! If you don't mind, when you get a chance to remove the piston, could you verify the 53.5mm measurement?
 


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#4
No problem. Getting the piston out was easier than I expected without an air compressor (the joys of apartment living, but with car parts everywhere).

Yeah, in the middle of the piston I'm getting exactly 54mm diameter. These calipers were rebuilt, so I guess the tips aren't perfectly square or something.

Let me know if you need any other measurements since I now have a caliper fully disassembled in my living room and I don't really need to reassemble it (they'd have to be rebuilt before going back on a car anyway).

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JDG

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Thread Starter #5
Awesome!! Thank you so much!


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