my 94 k1500 has been pulling to the left when braking and driving and seems to be getting progressively worse...like most problems that go unattended...just looking for a good starting point for diagnosing the problem

 

i had the same problem with my 97 i had to get new upper lower ball joint ty rods and front brakes mayb yours wont b as bad

 

Check your left front brake caliper,they sometimes get "dirty" or corroded and the piston inside the caliper will stick out a little.This causes drag on the left when driving. Also check the brake lines all around. Sometimes the rubber part of the lines swell shut. This disrupts the fluid from going in the caliper. So the piston doesn't come out as fast or far on one side. Causing it to pull when braking.

 

I second big chuck

A swollen or separated line on r/s could also make it pull left. If it is swollen or torn or separated it will sometimes restrict flow to caliper causing the right side not to work as well as the left subsequently pulling to the left.

 

well i got under it today and i have bad ball joints and tie rod ends...brakes seem fine but we'll see when i get the rest replaced

 

Prob Caliper like big chuck states. Mine did same thing. You can some times tell if you feel front rims for heat or you may smell brake pads roasting . if one is notably hot, thats the one sticking. I just took off wheel. sprayed caliper piston area with brake clean, then forced piston inwards with a pry bar on brake pad surface sprayed it with some more brake clean works fine now. If it comes back try a new brake pad That way the piston will ride farther inside caliper if that doesnt work your piston caliper prob needs to be replaced.