Hydro steering issues

OK, I've exhausted all resources I can on my steering issues. Has anyone running hydro steering with a double ended cylinder had this issue? When the front is locked in you can't steer the truck and going down the track the steering locks up? It use to do it a little when I had the d60 under the truck and a single ram cylinder. Last winter I went and put a rockwell under the truck and a new dual ram cylinder and it made it way worse. With the front unlocked I can barely steer the truck. Locked in can't steer it at all except straight. Swapped orbital valves and it made it worse. Just had the pump tested and it dead headed at 4k psi. Dad forgot to check the flow so he is going back in to have that check. Could it be possibly air in the cylinder still? Any help would be great before I scrap this entire setup and start over. What PSI are you running?

I don't know if this will help, or is related.
My stock 97 setup used to do something similar. I swear it would lock it up, not just cut power to the assist. It would be worse when I was using the brakes as well, and that's what scared me (hit the brakes in an emergency and now you can't steer).

I started with a fluid flush. It didn't do much (maybe it helped a little).
Then I swapped my power steering pump to AGR's largest drop-in pump. That made it go away.
Then it came back kind of and I noticed a leak at the hydroboost. It had a slight crack by the threads, so I swapped it with a used one, and filled everything back up.
It hasn't come back since.

I did notice that this issue was much worse in the winter. I'm thinking maybe the fluid being less viscous in the summer helped.

Sounds like it's not your pump, so I'd check lines, and confirm you don't have air bubbles. They can be a *****. I make a plug for the return into the reservoir and then just drop the return off the gear box into an oil pan. Then I start it up and cycle with making sure the res is full. A Motive Pressure Bleeder might work well on that too.

Are your U joints phased? Mine would jam up a little last year when I had it at a full turn in the pits because it would bind. I imagine it'd be even worse with a drop box that you can't disengage. Mine is still with a transfer case.

what is your complete setup?

Tee a 5000 lbs guage into 1 side of the steering cylinder, see how much pressure is actually getting there.
My system runs less pressure than yours and works fine, running a single 2" diameter cylinder.

As far as trapped air, usually just makes steering delayed, have to turn steering 1/8 turn before anything moves.
To get rid of all trapped air turn steering cyl ports straight up and crack fittings with steering pump running.

Trapped air causes situation where you can't seem stay in front of sled also.

You can tell if all trapped air is gone if after system is shutoff for awhile, you can turn or attempt to turn front wheels with pump off.
If steering wheel spins without turning front wheels, there is trapped air in cylinder part of the system.

You may check pressure and all it will be getting to cylinder, then you will have to change cyl geometry.

Make sure full voltage is getting to hydro unit, low voltage or if batt gets low will make steering go away too.

Looks like Northern Tool electro hyd unit has 3000 lbs relief valve setting.
Thats what I've been running.

Thanks guys. After tearing Everything apart I think I found the issue. I HOPE!!!! It seems when I did all this originally I used the auxiliary return port on the pump which was 8 yrs ago. So yesterday I took everything apart to find that the aux return is smaller then the main return I wasn't using. So I'm switching to the main return to see if that fixes all this. What it appears to be happening is the pressure side is moving way more fluid the the return can get rid of and locking up my orbital valve. Once pressure bleeds off on the return I can steer it again. The port pictured is the aux which is on the side under the pressure port. The main return is on top according to schematics I found for this pump.

DISTURBED said:

Thanks guys. After tearing Everything apart I think I found the issue. I HOPE!!!! It seems when I did all this originally I used the auxiliary return port on the pump which was 8 yrs ago. So yesterday I took everything apart to find that the aux return is smaller then the main return I wasn't using. So I'm switching to the main return to see if that fixes all this. What it appears to be happening is the pressure side is moving way more fluid the the return can get rid of and locking up my orbital valve. Once pressure bleeds off on the return I can steer it again. The port pictured is the aux which is on the side under the pressure port. The main return is on top according to schematics I found for this pump.

Click to expand...

Nice! That makes sense. Hopefully that's it.