When I drive the truck the brakes are dragging. I can park on a slight incline and the truck will not roll unless I press on the gas. I jacked up the truck and the wheels will not respond at all. The wheels Are very hard to turn. I just replaced a rotor on the front passenger side and the caliper. All the wheels were working fine And it drove fine for about a day. Now I am puzzled because all four wheels are not turning. Is there a chance it could be the master cylinder I’ve never heard of a master cylinder doing this. When jacked up you can’t really turn the front two wheels but with a lot of strength you can turn the back but not the front.
It could be the brake booster or the check valve. Start the truck, pump the brakes. If the are still locked after you release the pedal disconnect the vacuum hose to the booster. If the brakes release the check valve is bad. If the brakes are still locked pull the pedal up by hand or foot. If the brakes release the booster is bad.
Truck fixed!!!! I replaced the ABS Module (easy on my truck) and I drive the truck for a while and all okay. I drive the next day and again with the locking of all four breaks. Stumped again. So now I loosened the master cylinder line bolts and this released the locked breaks. I then replaced the master cylinder and now all is good. Wether it was only the master cylinder or the master cylinder and the ABS module I will never know. I would recommend that if your breaks are locking up all four or just two unscrew the master cylinder break lines enough for fluid to drip out and see if that unlocks them like mine did.