Nader Fotouhi

I have a 01 GMC 3500 Duramax dually with Allison trans. I drove the truck back from SP yesterday and when I started it this morning to go to work, the steering and brake act as is if I am trying to turn the wheel (does not turn) or brake (no power assist) with the engine off. I had the belt and tensioner replaced last week. I am guessing it has something to do with the computer, as I do not think that brake and PS fluids are the same or the cerpentine belt affecting the operation of the brakes. Has anyone else had this issues before?

Veloce Raptor

Brake is based on vacuum IIRC. PS is based on a belt driven pump.









Professional Racing and Driving Coach

SundayDriver

Diesel engines make no vacuum so there is a vacuum pump. I assume that is driven off a belt, as is the power assist for steering. Look for a thrown/loosen belt.

Veloce Raptor

Ah, it's a diesel....I didn't catch that, my bad.









Professional Racing and Driving Coach

Nader Fotouhi

Mark,

The serpentine belt and the tensioner were replaced last week. I have not noticed another belt, so I will check it out to see if needs to be tightened.

Thanks

the flyin' scotsman

The power brakes on the Duramax and previous Chev diesels get their assist through the pwr steering pump.

After the serp. belt and tensioner check I'd look at the pwr strg pump and the fluid lines leading to the brake master cylinder.

A pic of the 'booster' and pwr strg lines:

Nader Fotouhi

^

Thanks. I just finished reading the PS flush DIY at the "Diesel Place" site. It seems that I may have found the cause for, not only this problem, but also the "low boost" of my brake. The way I see it, it could be fixed with a simple flush, or I need to change the pump.