Engine Noise during Braking

[DonG]

I have had my new 2003 GMC 3500 D/A for only three weeks now so I am still getting used to the "normal" noises it makes.
Today with the engine running at idle with the hood open, I could hear a strange noise when my wife pressed firmly on the brakes. I could not identify the source except the front of the Duramax. The noise is hard to describe also, maybe like a soft hiss.
Is it possible the added load on the brakes added a load to the power steering pump and then to the serpentine belt? Never heard it before and I can not hear it while inside the cab.
Has any one else heard this before???

Thanks, Don

[chiefsshop]

the load you are refering to is due to the fact that these trucks use a hydraulic brake booster. Your power steering pump provides the hydraulic pressure to the booster unit, so when you hit the brakes the power steering pump gets under a load.

[DonG]

Thanks chiefsshop,

I knew there was a tie between the brakes and the power steering, but I had never heard this sound before. The brakes work fine and I even tested the ABS system. Worked as expected.

Don