I have a bead blast cabinet that I have been using for smaller parts, but my compressor is undersized for extended blasting. I'm ready to powder coat and put the calipers on my chassis so for $40 I went ahead and dropped them off to a local media blaster. They were already split into halves and bare. I included a single set of small pistons and a single set of large pistons with seals and explained to the guy when I dropped them that they could easily drop the set into each half as they blasted to protect the bores. His response was that the stainless bores are much stronger then the cast metal and they've never had any problems blasting around them unprotected.

Got a call last Wednesday that they were done and I could pick-up by 6 or they will be closed the rest of the week for the holiday and will be open again Monday. I picked them up just before close. They were all in a box together like I left them and looked nice and bare. I took out one half and the cylinders looked fine. Not until the next day did I really go through them to find that the two halves that I left the pistons and seals in had issues. Looks like whoever did them had pulled the rubber seals of the tops of the pistons and just blasted away into the bore. When I pulled out the gritty pistons, the top half of the bore was completely blasted leaving the lower smooth.

The way I see it they ruined 1 front caliper and 1 rear caliper. I know the brake hone I have is not for stainless and not sure if there is a worth while way of polishing them back smooth. Even then I'm concerned with the size of the bore after and it sealing well.

...Going to make a phone call this morning and see what they say. I expect replacements Delcos as mine were original. Hopefully it is not too much of a battle.

 

the bores dont seal the brake fluid, they are a reservoir for it, the o-ring or lip seal on the piston is what does the work. not sayin they did a good job , but if the sealing surfaces are ok , there may not be an issue

 

I understand that. It is the majority of the stainless steel sleeve that is now rough blasted where the o-ring would seal against. If I was to assemble as-is the o-ring would be torn up in no time.

...I realize I used "bore" and "cylinder" throughout my explanation. By each I meant the stainless cylinder wall.

 

have a machine shop replace the sleeves.

 

And send the bill to the idiot who blasted the bores all to hell!!

What kind of "media" did they use?? I worked in the vacuum coating industry for many years, and we used either steel grit or glass beads to clean off our chambers' interior parts. I have a PhD in blasting, and all I'll say is that it takes a TOTAL MORON to screw up stainless steel parts.....