I have a 94 pickup that seems to be predominantly using one side for braking and wonder if anyone could suggest some causes. The front pads were worn down to the audible indicator so I bought a set of pads but only installed one because upon inspection the pads on the other side were almost the thickness of the new pads. When braking normally, I do not notice anything unusual, but when braking uncommonly hard, there is a noticeable pull.

 

if one side was “almost new” while the other was worn, the new side (with the unworn pads) isn’t working properly. could be seized pistons, the pads could be frozen, the lines could be blocked or soft. you’ll need to determine the actual cause by testing.

 

The caliper isn't hard to work on.
Some caliper rebuild kits don't include the o-rings between the two caliper halves, so check the kit before you break it down that far.
I used a small wheel cylinder hone to clean the cylinder walls.
Toyota has a rubber grease that works well on the pistons and rubber seals.(08887-01206 Lithium soap glycol grease)

Sometimes techs would use clamps to pinch off the brake hose to minimize their brake bleeding when done with the repair. These aren't great. Pinching a rubber hose like that can break down the inner lining of the hose and eventually clog the caliper.
If the hoses are questionable/old/show signs of pinching it might not be a bad idea to just replace, regardless if they're an issue now,

​​​​​​​Let us know what you find.