brakes

The pins can carrode but if the truck is being used they shouldn't bind up. This type of truck is prone to the brake hose collapsing at the bracket crimped around it to hold it clear of the tire. The hose will collapse on the inside holding preasure on the caliper. To check this jack the tire clear of the ground and spin it. Press and release the pedal and check the tire again if it won't spin then wait 5 min's and try again. If it spins then it the hose. The preasure drains back slowly through a bad hose. Steve

worn brake calipers or rubber lines are clapsing