Did a flush on my 07 Duramax Hydroboost system today. The fluid was most likely in there since truck was new (bought truck a few months ago).
The old fluid smelled burnt and was black black black..
The results were amazing. Steering is much smoother and brakes feel much better.

I used the procedure detailed here:
http://www.duramaxforum.com/forum/di...ost-flush.html

It's super easy. Takes abt 15 mins and cost me just under $35 for new fluid and 7' of 5/16" fuel line.
I'll be doing it at every fuel filter change from now on.

Think this would also work / same hose on the 6.5 Turbo Diesel?

Thanks for sharing. I've never heard of this, but I'll likely give this a whirl on my 2500HD/8.1 with 100K miles.

Have you done anything with the steering shaft bearing?

I'm not familiar with the 6.5's, but I wouldn't be surprised if it had the same hydroboost sys.

With 100K miles on that fluid, I'm sure you'll feel a significant improvement.
A few notes abt the flush procedure in case you didn't read the entire thread:

1: Remove the p/s cap before removing the hose shown in the pic and do not re-install the cap on the power steering reservoir until you're all done. Both can make fluid come out the disconnected hose.

2: Make sure the drain hose you connect is connected securely to the nipple. I used a screw-type hose clamp. One poster mentioned his popped off and and made a big mess.

3: When the brake pedal is released rapidly, there's some recoil on the drain hose. Enough to possibly shoot the hose out of the drain pan and once again, make a big mess. I pushed the drain end of the drain hose thru a large 1/2" drive socket then ty'wraped it so it could not easily come back out. Worked fine. Actually the ty'wrap was over kill since if was a pretty snug fit to begin with.

4: If you buy a 1 gal jug of P/S fluid, use a tranny funnel to put the fluid into the P/S reservoir. I tried using a small funnel and made a mess.

5: Don't omit the step that says to put something over the sharp edge shown in the pic. That edge on my truck is VERY sharp. There's also a clip nearby that lay'ed open one guy. Doesn't take much now days to have me bleeding and not even know it!!

My steering shaft bushing/bearing (green one above the brake pedal) was making a scary loud rattling/clunking sound when I bought the truck.
Sounded/felt like something major was loose.
Tried the hose clamp fix but it popped off after a couple of days. Used a 2 1/8" muffler clamp and I haven't heard a pep out of it since.

Ref post #22 of this thread:
http://www.offshoreonly.com/forums/t...duramax-3.html

Brian,
I'm surprised at you being the keyboard jockey that you are, and un-aware of all this info! Did you get hit pretty bad from the storm? I need to do the hydro-boost flush myself, never really liked the pedal feel on my truck. It stops fine, but just different. I always figured it was the GM system.

been doing this for years. the thing you will most immediately appreciate is the improved pedal feel!

I really don't use the brakes much since I installed the train horns; and no issues with high speeds steering either.




My area of VA got around 14" snow, 2" of ice, and another 3" of snow; back to back to back. It made for a mess, but my CheBroLet loved it. I had to rescue a friend in the middle of the night when he lost the transmission on his Nissan Frontier trying to navigate an unplowed road with his wife and kids in the car. Once I got them home, I pulled a couple folks out of ditches on the way back home. The DC area got beat down REALLY bad, 28-36+ inches. It's the 2nd worst I've ever seen here (Jan/1996 being the worst). Everyone knows how well the government works here, and folks are NOT happy with the response. Some folks I know around DC had not been plowed 4+ days after the storm stopped.



Back to the truck...
I've been experiencing some steering sluggishness/restriction as if my PS might be dying; but only once in a great while.
I'm going to try this flush trick.

In fredericksburg we got over 2' killed business...back to this yes the P/S like any other oil will break down over time, some vehicles use a cooler and some do not, but as you know most all boat setups, using about the same pump do use a cooler, years ago when I worked for ford, when the new(at the time) CII pumps came out(plastic housing) they would kill fluid very quick and turn black, did lots of flushing and adding additives back than..

Steering rattles usually from two areas. The most common is the shaft as its collapsible in the event of a collision. GM uses a grease to "dampen the rattle". (inside the shaft)

We would change them out but the rattle returns after engine heat moves the grease to bottom of the shaft..

Just remove the shaft.. Move it in and out 15 times to re-align the grease already in there and problem solved.

The lower column bearing thunk noise has no option other than replacing it. do the steering shaft first see if that helps

Just to confirm, this procedure, right?:

https://www.youtube.com/watch?v=THA4HoLPKfc