Q: The brake pads were changed about 1 month ago, but until yesterday, the truck was driving fine. Now all at once, both front brakes have seized up and I'm trying to figure out why. It doesn't make sense that both calipers would fail at EXACTLY the same time. My father suggested that the master cylinder is bad, but I don't want to jump to conclusions... Has anyone ever had this problem before? What should I check first? And if all else fails, how can I be positive that the master cylinder is bad? The metal brake lines were recently changed and flushed by the dealer, and there is plenty of fluid in the master cylinder. Any and all opinions are very much appreciated! Thank you in advance. markusfarkus, what you described is exactly the same as the problem I am having. I think that you may be right and I'm going to check this first thing tomorrow morning.
A: This happens alot. DOT 3 brake fluid absorbs moisture over time a corrosion ridge forms on the caliper bore and or piston. Water is heavier than brake fluid and falls to the lowest point in the system. When you push the caliper piston back to install the new thicker pads the piston seal is now riding in the area of corrosion. The seal can only flex so far to release. The brakes "sieze" because the piston is stuck in this area of corrosion instead of being free in the bore.. Crack the bleeder, if the piston presses back easy it is a brake hose, if it still wont press back it is a caliper problem.