Special tools

On the front disc brake kit, the outside of the rotor is sealed by what is called a dust cap. This keeps dust (or more importantly, water, dirt, and other yucky contaminants) from fouling the outer bearing. The cap has a flange that just presses into the rotor.

Here is the rotor end where the dust cap goes.

Like so. Of course, it is not inserted here, I have it just laying on the rotor. You can see the gap of about 3/16".

The cap just gets (for lack of a better word) pounded into the rotor until it is seated. There is an interference fit that keeps the car in place, it doesn't just push in by hand. The cap deforms a little to fit and remain snug. Normally I would just hold the cap and tap around the edges with a hammer, possibly also using a flat tapered punch, or more crudely, the end of a screwdriver, to really get the flange seated tight.

The thing is, the style of wheel I am using does not cover the rotor end and dust cap. They are supposed to poke through the wheel and be exposed, it is part of the look. So I want the cap to look nice, and not have all these little dents showing around the edges. What to do?


Make a special cap installation tool, of course! I must confess, this is not my original idea. I once bought a special set of wheels for my dragster, and they came with a tool like I will make.


At my local home improvement store, I quickly found a PVC fitting that fit over the cap end, registering on the flange. I will put this on the cap flange, and pound on the other end to seat the cap. Except it's kind of a sloppy fit, the cap doesn't center in the fitting end nicely. The fitting is a tad too big.

Ah, here we go. The other end of the fitting is threaded, so it has a smaller inner diameter. Of course, it is a little too small for the cap to fit in.

I chucked a drum sander tool into my drill press. I started sanding out the threads, around and around. I stopped a couple of times, checking the fit of the cap.

Within probably 60 seconds total, I had bored the fitting out to an acceptable size. The cap fits in nicely.

Like so. Now I can use the fitting-pounding-tool and do a nice installation, while keeping the cap unmarred. BTW, the fitting cost $.98, making this simple and economical, just like I like.