I replaced the front brake pads on the RKC yesterday. When I went to install the stationary pad, I noticed that the threads were missing in the mounting hole. I took it back to the dealer, thinking it was defective until he told me it was self tapping. I would never have thought that, since I assumed the backing material was steel.

What is the backing material made of? Some sort of ceramic? That self tapping screw hole seems kind of cheesy to me. I also figured that maybe the MoCo switched to something other than steel due to heat build up problems.

 

Did you try a magnet on the backing plate? They've been self tapping since I've been riding Harleys, at least 22 years.

The bolt is a "tri-lobe" thread that is slightly triangular in shape when viewed from the end and it's a very hard alloy steel. It has no problem rolling a thread into the softer backing plate. What I do is start the bolt into the hole with the brake pad laying flat on the bench, then, when I have some starter threads, I remove the bolt and intall the pad. The bolt goes in easier this way and there's less chance of starting the bolt crooked.

 

No, I didn't try a magnet. When I looked at the hole closely, it looked terrible. Kind of like what a hole would look like if you drilled into mud or plaster. It was wallowed out badly for the first 3/32" or so then looked better down into it. That's why I was thinking ceramic. I've never seen a hole drilled into steel that looked like that. Maybe there is some coating on it that's throwing me. I also figured that triangular bolt to be fairly cheesy. The parts guy showed me the triangular shape.

Well, a guy learns something new every day.