zullo

I'm trying to determine how much drag is acceptable between pads and rotors. I've been having problems warping rotors (track duty) and it has been suggested that my pads are dragging.

Well, they are dragging but I don't know if too much... When I remove a (front) wheel and turn the hub, there is fairly stiff resistance. No way could I spin the hub freely. With the wheel on, however, I can spin the wheel easily.

Too much? I've tried adjusting the brake pedal but have been unable to free the rotor up appreciably. All advice appreciated!

ArcWelder

It's easier to spin the rotor with a tire mounted because you have a mechanical advantage. You can measure the amount of dragging by wrapping a rope around the lugs, pull the rope with a pull guage and read the amount of force it takes to turn the rotor. I don't know if Mazda has a spec listed in the manual however.

The brakes should be self adjusting if everything is working properly.

Possible things to look at are:

Sticky pistons. You may need to rebuild the calipers.

Stuck brake pads. They should be able to move in and out freely.

Check the free play in the brake pedal. It should be adjusted so that there is no pressure exerted on the pads when the pedal is at rest.

zullo

Thanks, yeah, I understand the mechanical advantage thing Just trying to provide some relative measures of "drag".

This is my concern. You say "no pressure exerted on the pads". I have some pressure (certainly enough to draw heat, which could cause warping). Since I've tried adjusting the pedal, it looks like a caliper rebuild is my next step.

---> just making sure there really is a problem before I spend the time and money on the rebuild. <---