My truck is pullinghard to the left when under braking. Any idea what might be wrong?

Thanks Tom

 

A bad flexible brake line or a sticking/draging right side caliper that is getting hot and has reduced stopping power due to fade. Could also be you have a wheel bearing going bad.

 

Mine was pulling pretty good when I bought it. I cleaned and lubed all the moving parts and it has been stopping straight ever since.

 

Worn out track bar will pull when braking and is very common.
Have someone turn the steering back and forth slightly while you watch the driver's side joint.
If you see any play at all in the joint it's time to address it.

 

I had the same issue earlier this summer, ended up being a bad front brake caliper. Replaced both sides with new calipers and have not had anymore pulling issues under braking.