Reply to "Heat causing caliper rub?"

Khan,

If your brake master cylinders have what are called "residual check valves" in them, then this could be the reason for the brake "drag" when hot.

The residual check valve causes a small amount of pressure (~2 to 5 psi) to be retained in the brake lines when the brake pedal is not depressed. The brake fluid in the lines heats and expands, but the residual check valve allows any excess pressure that would have built up in the brake lines to be bled back into the master cylinder.

Let's say that the check valve has a rating of 2 psi. This means that the max pressure that will be present in the brake lines will be 2 psi (when the brake pedal is not depressed).

As the brake fluid heats and expands from whatever heat source (engine, exhaust, brake pad friction....), the check valve will only allow 2 psi to remain in the brake lines. When the engine is shut off, further heating to the brake fluid may occur due to the engine's "heat soak". But the max pressure in the brake lines will only be 2 psi.

When everything cools, the brake fluid contracts, and the pressure in the brake lines drops below the 2 psi check valve rating.

This may not be the cause of your brake drag issue. Just the normal expansion of the pads, rotors, and calipers caused by normal braking will cause some drag when hot and less drag when cold.

A heat shield certainly won't hurt and it may solve your issue. You might try a temporary heat shield held in place with straps (of some sort) as a test before fabricating a nice clean sexy looking permanent one.

John