The reason I chose not to rebuild the calipers is that I had non matching calipers (like that when I got it), and I tried to rebuild one of the bendix ones, and I couldnt get the dust boots back on. Then I decided to buy an ATE caliper and try rebuilding that one, but the pistons wouldn't come out. I only have one day off a week, so just to rebuild a caliper could end up being a 3 week project, and I already wasted money buying 2 calipers I couldnt rebuild, and 2 rebuild kits for the bendix calipers. And the price for rebuilt ones is about the same as buying a junkyard caliper and rebuild kit. BTW, I called and politely but firmly asked yo be sent a label to return the incorrect caliper and they did send it, so thats taken care of at least. Now I just hope I don't have to replace any of the flex lines, because I don't think they will come off without destroying the fitting on the hard line. I don't intend on even trying it unless I have to.