Front Brake Problem, please advise.

i had that problem on a pete dumptruck. the drum was warped really bad as if it were bent.

lift the front off the ground and spun the tire, you could actually see the spacing between the brake and drum vary. mine was the right side.

 

as drums get warped. they require more and more pressure. becuase the drum isn't perfectly round. so it's not making 100% contact with every square inch of the brake shoe. the more it warps, the less actual contact.

since you've only got one drum with the big problem. it's not working as hard as the other good drums. your applying more pressure then needs to be to get the one drum working. so the other drums are working harder then need be. which means wearing those brakes faster, making those drums hotter and they'll eventually start warping.

if you want to keep the repairs down to a minimum. best to fix the problem. cuz problems only get worse.

one of my first cars i had was a 75 plymouth duster. 4 drum brakes. brakes sucked, pedal was like hitting a brick wall. had all 4 drums machined. brakes worked like a champ afterwards.

unfortunately, truck drums don't get machined, they get replaced.