Been having a few issues with the back brake on my 99 RKC. It has Performance Machine calipers all around. Recently I had to do some work/maintenance to the caliper, replaced the pads, flushed the fluid. Well, at first, the brake was dragging, but the rear rotor and caliper were very warm to the touch. The fronts were cool. I thought I had a bad wheel bearing, turns out it was the brakes. Re-bled the lines, thought all was good. I'm still getting quite a bit of heat from the rear, although I don't hear it like I did before. Is heat normal for the rear? To be honest, I never checked it before, so I don't know if they normally run hot. Should I just rebuild the caliper? Any thoughts or advise would be appreciated!

 

Heat is not normal. You are probably suffering from either the pads or pistons not retracting properly. You may solve the problem by simply cleaning the caliper around where the pads fit, to make sure they are not catching on the caliper body or pins, also carefully cleaning around the pistons, so they can move freely.

 

You may have a caliper piston sticking.

 

would it be worth it to flush out the current fluid and upgrade to DOT 5 when I rebuild the caliper?

 

Use the correct brake fluid for your bike. If it has DOT4 on the reservoir lid (and in your owners manual), use that. DOT5 is not compatible with any of the other DOTs and the shouldn't be mixed with them, but DO use it if your bike says you should.

 

Every bike I've owned, the rear rotor runs hot. Obviously, temp depending on how much the rear brake was used and when you check it after you ride.
Jack the rear up, put in neutral and rotate wheel, listening and feeling for noise and resisitance. The wheel should not be hard to turn but wont spin freely like the front. You'll hear a slight drag from pads and belt sound.
If your brakes are working good and no excessive drag or rotor bluing, I wouldnt worry about the heat.

 

Digger, what PM caliper do you have on the rear?

As mentioned, bluing is the best indication of too much heat. Be sure to do the maintenance on all your calipers that Graham suggested.