one could be the lines need bleeding
A blown out rear axle seal will cause grease to leak out into the brake drums
Brake wheel cylinder or axle sealBrake wheel cylinder or axle seal
Excessive brake pressure, or brake pressure imbalance Front/Rear.
You have to remove the center of the axle plate and the axle to remove the brake hub.
loosen up the rear axle nut and loosen up the axle adjusters so the rear wheel moves forward, Now remove rear brake caliper from rear brake caliper mount and the remove rear axle and lower rear wheel and slide belt off rear pully. and remove the rear wheel. http://www.ronincycleparts.com
Most likely cause is a failed rear axle speed sensor. It is located on the top of the rear axle. Without checking codes it wil be hard to know for sure.
To replace a rear axle seal in a Nissan Titan, first, lift the vehicle and secure it on jack stands. Remove the rear wheel and brake components to access the axle. Then, remove the axle nut and pull the axle out of the housing. Finally, replace the old seal with a new one, ensuring it's seated properly, reassemble the axle, and reinstall the brake and wheel components.
Not unless you also change the wheel hub. This might require a complete rebuild of the rear axle.
It could be at the wheel brake cylinder or a junction at the rear axle.
Proportioning valve
Proportioning valve
Proportioning valve