[DaBlue1]

Originally Posted by kennetht

.....Why would it stick in cold weather in the mornings, but when its a warm morning, it does not stick?

Rubber hoses freeze and become very stiff when it's below freezing. They can also alter pressures in a pressurized system.

Is your bike stored outside? What is the condition of your brake hoses?

Another interesting fact about brake fluid-
"One of brake fluids most important characteristics is in fact its ability to absorb water! It is designed to absorb water! Diffusion allows moisture in the air to permeate microscopic pores in the rubber brake hoses and the various seals in the hydraulic brake system. This moisture would then rot out the internals of our brake system if it wasn’t absorbed by the brake fluid. In extremely cold weather it also stops this water/moisture from freezing in the brake system. This feature comes at a cost, which is, that water contaminated brake fluid reduces its performance. But brake fluid composition and therefore its effectiveness can also be altered by its working environment, because the brake system generates extreme temperatures, some of this is transferred off the disc pad and rotor into the brake caliper holding the disc pad and this heats up the brake fluid that flows within the brake caliper. To give you some idea of this in action, should your brake system have 3.7% of water trapped within its brake fluid, the boiling point level of your standard brake fluid is reduced from 205 degrees Celsius to 140 degrees Celsius a thirty percent reduction! So we now know that moisture will reduce the effective boiling point by almost 1/3. There are many different types of brake fluids with many differing effective temperature ratings to handle this event. "