I was in the process of rebuilding the calipers on my 65 mustang. One side was fine, the other side was different internally, so the rebuild kit is not working. In the piston cylinder on the 65-66 caliper, there are 2 grooves, One for the seal for the piston, the other groove for the piston dust cover.. This caliper is fine.. The one Im having problems with, only has 1 groove in it, and there is no spot for the dust cover. There is a serial number, but its not a ford part number, so i have to assume its a after market caliper. It looks like it might have a spot externally to put a dust cover, but hard to tell. Anyone know what im talking about or what i need here? Or am i EFF'd and need to buy a new caliper?