Help! F250 disk brake problem-new pads too thick

[kknip]

I bought new rotors for my 72 F250 Camper Special,new pads from Advance Auto,the pads are too thick,they both won't fit in the caliper.I talked to the guy at NAPA and he found on his computer that the rotor should be 1 inch thick,mine are exactly 1 inch.The calipers say dayton on the sides,and the pistons are pushed in all the way.Advance only showes one pad avalible,they looked in 4 more boxes,all are the same thickness.I thought about finding a NAPA store local that has some pads in stock to see if they are the same thickness.If they are I might put mine on the belt sander to make them fit. They don't need much removed,but I shouldn't have to do that.Any ideas?......

[fordman]

usually it is the pistons not pushed in all the way. since your are i am not sure what to say without seeing them. maybe the rubber is bunched up around the pistons and not giving enough clearance.

[kknip]

I will check and see if the rubber is the culprit tomorrow,I didn't think it was in the way,but it might be. Thanks Fordman.

[convincor]

are the pistons compressed all the way back with a c-clamp?
The lip of the piston should be flush with the caliper.
They could be rusted up at the bottom of the bores. You may want to concider rebuilding/replacing them.
See if they can bring in a rebuilt for you to do a comparison.

[kknip]

Well,I removed my calipers and tore them down,they had some rust and goo in them,but were pushed all the way in.I ordered the seal kits and pistons today.I put two of the pistons in the caliper without any seals after I got everything cleaned up,temporarly installed them and tried to put the pads in.They still would not go in.The pistons were not flush,but were all the way down.I called several napa stores to see if they had pads in stock and if they would measure the thickness.None had them in stock,so I called auto zone,they had a set in stock and the guy measured them with a dial caliper.They measured almost an 8th smaller than the pads I had! That means almost a quarter of an inch clearance that I needed!!I went down and bought them,and stuck them in place where I still had the caliper temporarly installed and they fell right in!!! I am going to take the other ones back to advance when I pick up my seal kits and pistons tomorrow and show them the difference.I guess if you had wore rotors,they would fit,but not new ones.Man,I'm glad that mistery is solved!!!