sum times no power steering when I turn left ?

[freight shaker]

when turn left sum times my power steering goes out ? but when its raining its fine or if im really light or bob tailing its fine what could likely be the cause steering box, kingpins, I dont think its the pump but im not a mechanic ?

[Kranky]

Something in the steering linkage or axle kingpins is binding when turned to the left.

Rain makes it easier to turn the wheels because the tire/road interface is "lubricated" with water, reducing the effort needed to overcome the binding parts.

Running bobtail or lightly loaded also requires less steering effort to overcome the binding.

If it was the pump, the problem would exist whether turning right or left.

But:

It's pointless to discuss this here.

That truck should be in the shop now, before it kills somebody.

[Rev.Vassago]

Possibly the poppet valve in the bottom of the gearbox.

[freight shaker]

thanks guys for the reply I just need a general idea of what it could be before i take it to a shop and let them charge me hours in labor to find the problem.