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Hyd. Steering Orbital

5K views 56 replies 10 participants last post by  XJay 
#1 ·
Looking for some help on an orbital valve selection. I just changed my steer cylinder from 2" to 2-1/2" dia. X 8" stroke, 1-1/8" rod dia., single-ended.
I had a Danfoss orbital on the shelf (part #B 200 ON) that I hooked up and the displacement was about perfect, 3.5 to 4 turns lock-to-lock). Probelm is there's an issue with the valve as it will only turn to the left, and I'm not a nascar driver...
Long stroy short, I found out the displacement on that valve is 12.2 cu.in. (200c.c.) So I'm trying to find a Char-Lynn (Eaton) valve with similar displacement and have not had any luck dealing with parts stores or searching the web.
Thx, Jay.
 
#6 ·
Really scratching my head now! New orbital is doing the same thing, turns left no problem, absofrickenlutely won't turn right. The p-steering pump instantly goes into bypass as soon as you try and motion the steering wheel to the right.
Even tried switching the 2 lines going to the ram at the orbital and it will still only turn left (but steering wheel direction is now backwards).

The only thing I can think of at this point is that the orbital is not letting the return fluid to exit the cylinder when trying to retract the cylinder (turn right). It's just odd that 2 different orbitals would do this...

Or possibly my p-steering isn't suppling enough GPM to properly operate the new orbital? It is a PSC P-pump.

At a loss... :confused:
 
#8 ·
Ram is mounted behind the axle so out on the ram, or left turn, works properly. In on the ram, or right turn, no workee...
Steering wheel is hard as a rock and you can hear the pump bypassing as soon as you touch it to the right.
The wheel won't even turn right with the engine off, it'll turn left though.
Also tried cracking the lines at the ram and manually cycled it just to make sure it's working properly. This is the only way I can get the cylinder to retract, but of course it leaks all the fluid out.
 
#12 ·
Here's a quick sketch of my system and how it's hooked up. I can't see it being an issue with the ram or a line because it works with the other orbitals I tried. They were all just too slow for the 2-1/2" ram, not enough fluid displacement.
I did try swapping the L & R lines at the orbital, cylinder will still only extend, it just opposed the direction of the steering wheel.
 

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#14 ·
Ya pretty sure it's hooked up right. Also the orbital is a "non load reactive" type so it's not a "self-centering" vavle.
To me it can only be 1 of 2 things:
1. The orbital is not oppening the port to let return fluid back out of the cylinder on the piston side, when adding fluid to the rod side (turning right).
2. The power steering pump isin't generating enough pressure or flow for the orbital to work properly. Although it works perfectly with a "slower" orbital, it just takes 9 turns of the wheel to turn.
 
#16 ·
Just spoke to Kevin at PSC, he's never heard of such an issue lol. He verified that the PSC pump that I'm running is plenty adequate for my set-up. He also said he doesn't think it can be an issue with the orbital itself since it works properly in one direction and that all lines are hooked up correctly. He said only thing it can be is an issue with the cylinder itself.
I'm going to try putting my old cylinder back on.

One other thing I just remembered from when I was originally setting up my hydraulic system is that I had to put shims (washers) in between the mounting bracket and the orbital itself to space the steering shaft out of the orbital a bit. Without the shims, it wouldn't allow me to turn right or left for some reason??? Almost like the steering shaft splines were bottomed out in the orbital, and not allowing it to turn.
 
#17 ·
Welp, I found the needle in the haystack last night. Not gonna lie was a stupid mistake on my part. Put my old ram back on that I know is good, same issue, can't turn right. Decided put a different orbital on, and while transfering the fittings from the new orbital I just happened to check the fittings over and found that the one on the RH turn port was different than the other 3. For some reason it only had 4 tiny holes inside to allow fluid flow rather than being "hollow" like the rest. See pic below. :ffs:
BTW thanks for everyone's input!


Anyway, now that it's running, steering ratio is about perfect; 3-1/2 turns left, 2-3/4 right. I find it way slower than my old set-up though and takes more effort to turn the wheel. Can't just spin it with one finger anymore. Not really happy with it. I assume the only fix would be a higher output p-steering pump???
 

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#19 ·
I have no idea about the internal function of the orbital but the question was asked when I spoke to PSC and he said that the pump I'm running is plenty strong for my orbital.
When I was running a smaller 2" ram and smaller displacement orbital, I too could turn the wheel fast with one finger. Approx 3/4 of a second per revolution maybe.
Now with the new set-up it's like 2 or 3 fingers on the wheel and like 1.5 seconds per revolution. I was thinking steering effort would be easier with s bigger ram, guess not I'm hoping it'll be better with the fluid at op. temp too. Will take some getting used to I guess.
 
#20 ·
OK took it for a quick ride and I'm really not happy with it. The orbital ratio to steering wheel revs is perfect, but steering is way too slow though. Can't turn the wheel fast enough to keep up with which direction you want to go while driving around.
One thing I found interesting is the more reading I do and the more people I talk to, I'm finding that actaul PSC pumps aren't all that great and lots of people easily burn them up.
A buddy of mine has gone through 2 of them. He switched to 90's chevy P-style pump off of a truck with hydro-boost and hasn't had an issue since. He said he took the upgraded spring and stuff out of the PSC pump to boost pressure, and used the PSC can cause it has the single AN output for the pressure line.
Anyone have any experience with a hydro-boost power-steering pump?
 
#24 ·
Of course a bigger cylinder requires more volume, that's why I went from a 7c.i. orbital to a 12c.i. displacement.
The issue I'm having is that the pump I'm running was verified by PSC to deliver enough flow/pressure for this combination, when it obviously does not.
Unless I'm missing something? Are 3/8" lines too small now maybe?
Also, I would assume a hydro-boost pump would produce greater flow but don't know for sure. Can anyone confirm?
 
#28 ·
I'm not up to snuff on my AN sizes but I think I'm running -6 (.344" ID).
My hyd. hoses all say 3/8" on them and my fittings are all 3/8"JIC. All except for the hose between the reservoir and the pump, it's 3/4"ID and about a 10" straight shot.

The only time I noticed a bit of noise coming from the pump is if I turn the wheel lock-to-lock several times fast, it'll whine a bit after 3 or 4 times doing this.
 
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