2nd Gen Non-Engine/Transmission no steering when braking

[Mopar_Tim]

for a while i have been fighting steering issues when i was slowly turning the steering was super tight ... but when i revved the engine and kinda powerbrake it it got easier so i figured the power steering pump was on its way out ... .



i changed that today pita ..... and now the idle steering is great unlike before but now when i step on the brakes and try and turn (not moving) i cant hardly move the wheel ... . but as soon as i let off the brakes i can steer the truck with one finger





i am assuming i have hydro boost problems ... . but i want some of your opinions



thanks in advance

 

[Gary - K7GLD]

This could be interesting! :-laf

 

[Mopar_Tim]

why do you say that ... .

 

[bnbrown]

I am assuming the system is full and air bubble free...
the problems I have had with the hydroboost gave me no PB, but steering worked fine.

 

[Mopar_Tim]

well i think so, i filled up the res. and with the wheels off the ground i cycled the steering about 50 times

then i started the truck and cycled them about 50 times with the wheels on the ground ... made a hell of a mess for a while till it stopped over flowing

then i want out and drove it in my neighborhood and made zig zags in the road for like 10 mins /\/\/\/\/\/\/\/\/\/\/\/\/\/

its not making any bubbles anymore

 

[DLausche]

I wonder if the screen filter on your PS pump could be partially plugged or something like that.

 

[Gary - K7GLD]

why do you say that ... .

Because the vacuum pump gets drive power ahead of the power steering pump, and it's all mechanically driven thru the same shaft - so it's hard to imagine a condition where the act of using the brakes can have any significant effect on the power steering pump ONLY when brakes are applied.



The only remote issue *I* can imagine, never having actually seen how it all interconnects internally, and to the drive gear at the front of the engine, is IF the drive gear is somehow loose on the vacuum and steering pump shaft, but still drives the steering pump OK until the added drag from the vacuum pump when the brakes are applied causes the gear to slip on the drive shaft.



But that's a WAAaay out there theory - like I said, this could be interesting!

 

[bnbrown]

On the 24valves the PB is hydroboost from the power steering pump vaccum pump only runs cruise control and HVAC selector. I would be suspicious of the screen... or it could be the pump is no good... when I replaced mine the first one I installed was no good (I was cheap and got one from Autozone after the one I got from NAPA was the wrong model and would have to wait over a week to order in the right one).

 

[Gary - K7GLD]

On the 24valves the PB is hydroboost from the power steering pump vaccum pump only runs cruise control and HVAC selector. I would be suspicious of the screen... or it could be the pump is no good... when I replaced mine the first one I installed was no good (I was cheap and got one from Autozone after the one I got from NAPA was the wrong model and would have to wait over a week to order in the right one).

That's right - I keep forgetting the power brakes on our '02's aren't the older vacuum operated ones...

 

[bnbrown]

That's right - I keep forgetting the power brakes on our '02's aren't the older vacuum operated ones...

Still not sure if it was a good thing... really annoying to not be able to steer or stop when something goes wrong...

 

[AKAMAC]

Try pumping the brakes w/o the truck running to bleed any air out of the n2 back up system. Maybe there is enough air trapped in the hydro-boost system to cause problems. Can't hurt.

 

[monkeyman]

Check your Hydro Boost, if its goes bad, that is one of the symptoms. When mine went all my brakes locked up and I lost steering.
Rick

 

[Mopar_Tim]

pumping the brakes did not change anything ... . how do i check the hydroboost ? i actually have another one in the garage that i planned to use on my project truck ..... but the 02 is more important



but i really dont want to change it if it is not the problem







but i have a feeling it is b/c 2 pumps doing the same things

 

[bnbrown]

The only test I know for the hydroboost unit is primarily for testing the N2 part. That test is to go to a nice open area and get truck moving i think it is 10mph shut it down and toss in neutral (so PS pump isnt turning anymore) and hit the brakes... if N2 is good you will still have PB... if not, no power brakes.

 

[BDaugherty]

Stock Dodge Cummins PS pumps just don't have enough flow to run the hydroboost and steering at the same time. The flow from the pump goes through a priority valve in the hydroboost which will provide flow first to the brakes and second to the steering. If your brakes are using all or most of the available flow, you won't have enough flow left over to provide steering assist. I've had 2 2nd gen Cummins trucks. One was automatic and one was 6spd. The auto was the worst steering offender due to the fact that you're always riding the brakes when slow speed manuvering. I took both pumps off the truck and sent them to PSC to be rebuilt and upgraded for increased flow. It made all the difference in the world and I tell everyone that I talk to that it was the single best thing that I did to either truck. I didn't have any problem with my truck being down for a week, but if you need yours to remain driveable, you can just buy their pump and send yours in as a core. I would also replace the seal at the rear of the vacuum pump while I had to PS pump off.

 

[bnbrown]

PSC are good folks to deal with, used to have problems steering especially when spotting a trailer, blew up a couple PS pumps. wouldnt steer at all unless you gave it some throttle to get the RPMs up, and then it would steer, until the pump blew up. I bought one of the PSC steering boxes and that made a huge difference for my problem.

 

[Mopar_Tim]

well today i drove it up to work again ... . now it wont turn at idle sitting still with or without brakes ... . and with brakes its almost impossible

i guess that's what i get for buying a parts store rebuilt ps pump

 

[Mopar_Tim]

i called and talked with the guys at psc ..... and i ordered there pump ... ... here is where i cant figure it out ... ... it was cheaper then the rebuilt pos and there are no used parts on it all 100% brand new