in a little more detail i'll explain what the last guy meant.if your truck is pulling to the right for example,it could be one of two things.whichever of the two things i list will be on the left side if it pulls right or the right side if it pulls left.that being said one cause could be the caliper slides on the left being stuck and not allowing the caliper to slide or the piston in the caliper could be stuck either way if the left side is not grabbing and the right is,there is the reason for the pull on braking.the other could be a clogged brake hose on the left side,not allowing fluid to the caliper causing the left not to work hence the right pull because only the right is working. hope this helps.should be relatively inexpensive the brake parts for these trucks are way cheap.