PSC load-reacting/return to center orbital

ROKRIG · Oct 12, 2009

After my last trip to Reiter when my full hydraulic steering control completely disappeared and sent me off the road and over the side of the hill, I purchased some new parts thinking there may have been a few components and layout issues that could have contributed to my roll. I've got a brand new 2" bore x 8" stroke ram installed, all new -6AN hydraulic lines with new fittings and decided to get a brand new 4.5 c.i. "orbital" from PSC as that is what had been in the rig when I bought it (as opposed to when I rolled, I had a 5.9 c.i. "orbital" from PSC installed). There were also two 90 degree bulkhead fittings in the floor previously that the L and R hoses utilized. I removed those, cut a larger hole in the floor and just ran straight lines from the "orbital" to the ram.

So, I was hoping this week that I might have fixed all the possible problem areas after completing these changes but as soon as I finished the top-off/air removal procedure and drove the rig around the block, I quickly realized that the problem was still there. Basically, sometimes when I'm driving (at any speed) I'll begin to rotate the steering wheel and it just spins giving no input to the wheels and absolutely no resistance at the hands. Of course I apply the brakes and sometimes, the control will come back and other times, the steering wheel just spins. A lot of time I have to just come to a stop, wait for a bit and then try rotating the wheel again to see if I get resistance. When I do I can steer normally and everything might be fine for quite some time. The problem is this lack of steering control just happens unexpectedly.

A very experienced buggy owner/driver (w/ full hydro) drove my rig around this weekend at Reiter assessing what he was experiencing as well as my reservoir, pump, orbital valve layout. After removing the ram, lines, reservoir and pump as potential culprits (based on their height positions, proximity to each other, proximity to heat (i.e. my header), the presence of an in-line cooler,etc) he seemed to think that there must be something with the load-reacting/re-centering "orbital" I have installed that is causing the condition I'm experiencing. He also mentioned that neither his nor anyone elses rig w/ full hydro he's driven has the "return to center" feature.

Sorry for the rambling but I'm baffled and it's just plain scary and frustrating to now be getting this condition a second time around. Does anyone have any suggestions? (btw, yes, I did call PSC and the gentleman I spoke to didn't have a solid explanation other than suggesting I get a much more expensive ram from them along with their 11.3 c.i. "orbital")

Terry

super samurai · Oct 12, 2009

what about the resivoir? the bottom tube feeding the pump is gravity feed only, so if the angle is to flat or it is not flowing could be an issue as the pump doen't suck the fluid in. other than that it could have a bad pump or to small of pump.:hi:

Binder · Oct 12, 2009

Many people including myself have that same orbital. It's not really self centering so I would forget about that....Are you sure you have the hoses hooked up correctly to the orbital valve?

johny5 · Oct 12, 2009

I did have a problem with my homemade steering column, mine was a stubby column that had an extension welded to it with plug welds in the side of it,

It would hold with some resistance but under a load it would spin.

On another note how many turns lock to lock 4.9 ci cylinder?
I ran a small one and it was 6 turns lock to lock, now I run a bigger one and its 2 1/2 turns , really nice when you need to turn

benw1 · Oct 12, 2009

Are you running a single ended cylinder? You're not 'supposed' to run a load reactive valve with a single-ended cylinder. Lots of people do it without issue, but the unequal volumes on each side of the piston in the cylinder are theoretically a problem for the load reactive valving.

Money Mark · Oct 12, 2009

Binder said:
It's not really self centering so I would forget about that....

I was the one to suggest that after driving it for a few minutes on Saturday......it deffinatly "goes back straight".:eeek: Why does it do this then? Not one single rig I've owned or driven have has this feature.

Binder · Oct 12, 2009

Money Mark said:
I was the one to suggest that after driving it for a few minutes on Saturday......it deffinatly "goes back straight".:eeek: Why does it do this then? Not one single rig I've owned or driven have has this feature.

It's a load reactive orbital which means you will feel feedback in the steering wheel from the front end. This gives it the ability to be used in a return to center system but more often then not offroad rigs have the front alignment and such in a way that it won't return anyways. It really should only return when on flat ground with equal traction side to side. Front locker engaged should make it worse too.......I doubt the load reactive feature has anything to do with the problem but who knows?

Pook · Oct 12, 2009

He could have lots of castor...

DSI is running the same orbital in his Ultra4 car, with no issues.

Mog9buG · Oct 12, 2009

If the problem occured with both orbital valves then the issue is probably something different. Does this system run a suction line from the res to the pump?

ROKRIG · Oct 13, 2009

Mog9buG said:
If the problem occured with both orbital valves then the issue is probably something different. Does this system run a suction line from the res to the pump?

Per PSC, I do have the suggested -10AN line coming off the bottom of the reservoir through a swept 90 degree fitting up to the input fitting of the same size on the pump. While the supply line from the reservoir does travel upward 9-10" to the input fitting on the pump, the consistent fluid level in the reservoir is always well above the height of the input fitting on the pump ( I'm assuming this is sufficient to provide the necessary gravity pressure on the fluid to keep it flowing into the pump but I guess since I'm not a fluid dynamics expert, I may be wrong)

I'm running a brand new single ended 2"bore x 8" throw ram from Surplus Center. The ram itself has SAE 8 female bores in which I have SAE 8 male/ -6AN male adapter fittings to which the brand new hydraulic lines are attached. At the orbital, the other end of the hydraulic line runs into the same -6AN / SAE 8 adapter fittings that were supplied with the orbital. These fittings are on the T and P ports as well

The pump is a brand new PSC P-series can-back pump (High displacement 1405 pump per the invoice) that I installed in lieu of the OEM pump that had the piggy-back reservoir. This pump is fed by the SR-100 remote reservoir from PSC.

The return line (or T line per the PSC diagram) does run through a 12" Derale heatsink fluid cooler (as suggested by PSC) before returning to the reservoir.

ROKRIG · Oct 13, 2009

benw said:
Are you running a single ended cylinder? You're not 'supposed' to run a load reactive valve with a single-ended cylinder. Lots of people do it without issue, but the unequal volumes on each side of the piston in the cylinder are theoretically a problem for the load reactive valving.

My next move was to replace the load reactive steering valve with a non-load reactive unit in hopes of fixing this issue

Robinhood · Oct 13, 2009

I would try moving the res. higher. I have seen many problems in steering system cause by the lines being ran below the intake of the pump. And what line are you using on the inlet hose to the pump, if it is not rated for suction it could be crushing under a suction.

briejer · Oct 13, 2009

I second the line from the resevior crushing(it needs to be vacum rated) The resevior has to be higher than the pump and as short of a hose as possible. I am also suspect that you are getting air into your system. You can have air sucking in when the rig is running, but not leak out when not running.

When its running look in the resevior for little air bubbles. Look for them at low rpm, high rpm, steering full left, full right. If you have ANY air bubbles you have a leak.

crash2 · Oct 13, 2009

briejer said:
I second the line from the resevior crushing(it needs to be vacum rated) The resevior has to be higher than the pump and as short of a hose as possible. I am also suspect that you are getting air into your system. You can have air sucking in when the rig is running, but not leak out when not running.

When its running look in the resevior for little air bubbles. Look for them at low rpm, high rpm, steering full left, full right. If you have ANY air bubbles you have a leak.

We learned that one.....

jimboy · Oct 13, 2009

How much spline contact do you have between the orbital and column? Do you have a pic of your orbital/column, mounted on your rig?

ROKRIG · Oct 13, 2009

The reservoir is higher than the pump and in fact, the bottom of the reservoir is about even with with the top of the pump. It's the -10AN 90 degree fitting at the bottom of the reservoir that puts the absolutely lowest point below the inlet of the pump.

The supply line (or suction line) is provided by PSC with the pump and reservoir and is rated for such application.

I've run the engine at idle and turned the wheels from side to side - no bubbles.

The steering shaft is the 11" variation from PSC and it is sandwiched in between the steering valve and the 3/8" dash plate that supports the two using 4 grade 8 bolts. Nevertheless...full spline contact.

I've just ordered a 7.3 c.i. NLR(non-load-reactive) Char-lynn steering valve that (with my ram volume) will give me approximately 2 turns lock to lock.

deerlick · Oct 14, 2009

I didnt know you changed all of those parts since you bought it. maybe with the original parts and the amsoil fluid i recommended you wouldnt be having any problems, it always worked flawlessly

ROKRIG · Oct 14, 2009

with the original parts, the system did work to a certain degree but the orbital was really noisey, I was getting strange feedback through the steering wheel and the reservoir was constantly puking fluid. so, I thought I'd just take care of those issues. well, it's been a little more trouble that I thought it woud be but I enjoy this kind of stuff and after all, it's my $$$ :;

ROKRIG · Oct 16, 2009

after further discussion with PSC, it sounds like the slight uphill climb the fluid has to travel from the reservoir to the inlet of the pump is causing the condition that I'm experiencing. so I guess I'm going to try to figure out how I can get the reservoir higher and still keep it within the boundaries of protection provided by the chassis

super samurai · Oct 16, 2009

super samurai said:
what about the resivoir? the bottom tube feeding the pump is gravity feed only, so if the angle is to flat or it is not flowing could be an issue as the pump doen't suck the fluid in. other than that it could have a bad pump or to small of pump.:hi:

this is what it sounds like to me, seen it happen