This has been an ongoing problem...often, though not all the time, when applying the brakes, the steering wheel pulls to the right. I've checked the rotor and pads on both sides and all seems ok...

When jacked up, If I step on the brakes and release them, the wheels will both be locked up and the free to spin as expected.

What else should I look for?

 

my brother in law has the same problem with his 95.. he replaced the left caliper and had no luck.

I am guessing the problem is a collapsed left brake line (the rubber one)? or could it possibly be a brake booster?

any help is appreciated

 

Mine pulled a bit when one of the bearings was going.

Also the hoses die after enough life and cause unequal application pressure. Sounds bunk, but I've heard lots of reports on here that the problem finally went away with new brake hoses.

 

Adjust your rear brakes, if one side is too tight it will pull to that side. Simply adjust the other side, in your case adjust the driver's side rear brake tight.

Mine will start pulling to the right a little when braking. When I'm a work after closing I'll back across the long parking lot and hit the brakes repeatly for about 200'. This adjusts the rear brakes and makes the right pull go away.

 

Tommy has it right, check the rears first.
Most important thing when backing up to self adjust is to come to a complete stop. I've had better success using the parking brake to self adjust than the foot brake.
Be forewarned though, these trucks are notorious for the self adjuster to not work. Many times you have to jack the rear and adjust manually.