GMC 3500 sierra Dully no brakes no steering?

[Liz]

Got in my truck this morning and had no function of the brakes or steering. Worked fine yesterday, what would be the cause of this?
Yes it is a diesel... Is that accessory the same as the serpentine belt?

[Molson02536]

Originally Posted by Liz

Got in my truck this morning and had no function of the brakes or steering. Worked fine yesterday, what would be the cause of this?
Yes it is a diesel... Is that accessory the same as the serpentine belt?

Power Steering/Hydro-Boost
Pump could have failed, sheared shaft…Pull the low pressure return line, is there any fluid movement? Prying out on the PS pulley with the serp belt in place will yield the broken steering shaft if there is movement.

If it's the valve, The PS pressure valve is very easy to replace-- remove the high pressure line at the pump- remove the large fitting that go into the pump- there will be a spring and a valve about 3/4 inch diameter and 1 1/4 long. This is the flow pressure valve. The valve is designed to bleed off the pressure through a small internal ball bearing -- after it reaches a set pressure. If debris gets under the ball, it will not build pressure. Common problem with many vehicles.

Good luck and keep us all posted on what you find, be glad to know you got your GM running 100% again soon, and this should cost about $100.00 for the warranty deductible.