I'm refurbing another set of Brembos for fun.... Tore them apart, and figured I had an excuse to finally buy some half-decent sandblasting equipment. Wifey and garage space had other ideas so I took them to a blasting shop. Chatted with the folks there for 20 minutes or so about what I wanted done but failed to explicitly instruct them not to blast the machined surfaces including the piston bores. Frankly, I thought not sandblasting machined surfaces, especially the piston bores was common knowledge. Obviously, I was wrong. Now I have some Aluminum paper weights. Might try to get them honed but not hopeful. I'm such an idiot.
They've been in business for nearly 80 years, have pictures of race cars and **** on the walls, seemed to talk-the-talk.... They charged an arm-and-a-leg. Really seemed like they knew what they were doing. When I addressed it upon inspection, they first said that they told me they were going to blast the piston bores (they didn't). I then asked them, if it was intentional, then why did they only blast some of the piston walls (as it looks like overshoot), and then they told me it was just no big deal, and that the pistons would drop right in and be just fine.
Having never rebuilt brake calipers nor having run a sandblaster, and using only the logic I was born with, it would seem to me that blasting the piston bore would be something you would not want to do. But, what do I know...
Did they start by working on military vehicles or something? I've never heard someone say pitted pistons were acceptable.
I haven't had Brembos apart, but the other 4-pots that I've had, the piston seal sits stationary in the caliper body, and slides along the piston. And the case halves are sealed together by a rubber quadring. I'd run 'em....
