Give that truck a brake.
Pull the master cyl,pull the wheels off and pull the wheel cyl. which will allow you to also check the brake linings.
REBUILD or REPLACE what is necessary.
I say that because when I bought my truck I drove it home with some brakes, tore it down to find out the rears were froze and the only brake I had was the fronts and the front cyls were in bad shape.
I know it's a lot of work plus money, but how else will you know what the true condition of the entire brake system is, plus your life my depend on those brakes someday.
Depending on how you intend on using the truck will dictate possible upgrades to the system.
Dan
