Power steering not working; Need help diagnosing (GC 2310)

[twaugh]

Hey everyone,

I was advised to post this in the MF forum. Hoping to get some input on diagnosing this problem.
Just picked up new to me GC 2310, 'assisted' power steering does not work, does turn manually, just hard to turn.

Couple things so far; steering wheel is wobbly (rubber bushings failed), the orbitrol appears to have been leaking from the shaft seal, leak appears old and does not appear to be leaking anymore. Someone before me has had the valve removed. Valve is a Danfoss OSPM 50; pn: 150L2084


I downloaded the service manual here:

https://assets.danfoss.com/documents/50338/AX152886482726en-000303.pdf

I consulted this generic Danfoss orbitrol valve schematic:


My spidey sense is telling me someone may have replaced the seals in this valve before and I am wondering if they got the timing wrong when they reassembled the valve, specifically the spring/ball check valve at pump line in. The assembly instructions for the valve give some detail on proper orientation.

Before I disassemble the valve, a few questions I was hoping to get answers to;

- How can I safely confirm flow from the pump (Line P)?
- Is it possible this valve is simply pooched and can't be fixed? It seems it is only oil and seals
- Will I need to bleed the hydraulic system once reassembled?

Looking for input from anyone who may have been down this road before. Any tips you can think to add would be appreciated.

-Ty

 

[Dmacleo]

never dealt with it personally but service manual for a 2400 says this:

FIGS. 33–35: The steering orbit roll (1) controls the flow
of oil to the steering cylinder (2). When the steering wheel
is motionless, pressurized oil travels from the control valve
(3) thru pressure hose (4) to the orbit roll pressure port
(P). Return oil travels from the steering orbit roll tank port
(T) thru return hose (5) to the front transmission cover (6).
Whe the steering wheel is turned to the left, the orbit roll
will send oil from port L, thru the LH steering hose (7) and
move the steering cylinder rod so the wheels turn to the
left. When the steering wheel is turned to the right, the
orbit roll will send oil from port (R) thru the RH steering
hose (8) and move the steering cylinder rod so the wheels turn to the right.

can you check for return flow to see if fluid pressure actually going into system?

 

[twaugh]

Hey Dave, thanks for that info.

If I am understanding correct; when the steering wheel is motionless, flow is travelling into valve through 'P' and out through 'T'.

I will see if I can check for flow tonight. Only way I can think to test is to start tractor and crack a line loose and see if fluid is passing.

I will give it a shot. Thanks again.

 

[Dmacleo]

thats the way I read it but I have not had a chance to visually look at mine on the 2400 to properly orientate myself.

 

[Tinhack]

Only way I can think to test is to start tractor and crack a line loose and see if fluid is passing.

That's death looking for a body!

Keep in mind that hydraulic fluid can be injected into the skin and warrants an immediate trip to the ER. In some cases, the only treatment is amputation.

 

[WranglerX]

Seems to me it would be safe to put temporary "T" fitting the "L" or "R" port line and attach pressure gauge to see if the is any activity ... Something must be happening because only way to turn front wheels is through hydraulic pressure in ram on front axle... There is no other mechanical link up...

IF someone was in to the valve assembly before you. I would be highly suspicious of how it was "repaired"......

 

[DMW]

​

- How can I safely confirm flow from the pump (Line P)?

Do yourself a favour and get a pressure gauge and fitting to connect to the lines. Check the P line and all outputs. Isolate the issue. Could it be a bypassing steering cylinder? A gauge will help.

- Is it possible this valve is simply pooched and can't be fixed? It seems it is only oil and seals

Seal kits are available. If the pump has been previously disassembled, were all the parts replaced? you won't know until you have taken it apart. Parts from the manufacturer/hydraulic shop can be significantly cheaper than from MF. I've read $600 difference if the pump needs to be replaced.

- Will I need to bleed the hydraulic system once reassembled?

No, just cycle through the cylinders, all the air will be eventually be expelled.

 

[twaugh]

I have been researching some more about orbitrol valves and hydraulic steering and came across these bits of info: Thought I would share as some may find useful for future.

"Manual Emergency Steering—A ball check valve allows manual steering in emergencies when pump flow is interrupted."

"Q: When the engine stalls or the pump fails, is it possible to turn with hydro steering ?
A: Yes, with most steering control units. There is a small check valve in the steering unit that acts as a pump and will supply enough fluid to the cylinder for limited manual steering in emergencies. The effect is very similar to standard power-steering with the engine off - i.e. with big tires at low pressure and locked axles it is VERY hard to steer, but it can be done, and if rolling at a good speed, isn't too too bad."

Also as per the Danfoss OSPM service manual for this valve assy, the assembly instructions mention:
"Place the emergency steering ball in port P." Port 'P' is line in from main hydraulic pump.
-> Obviously now I need to confirm there is flow coming from the main pump.

These remarks describe my symptoms exactly.

That's death looking for a body!

Keep in mind that hydraulic fluid can be injected into the skin and warrants an immediate trip to the ER. In some cases, the only treatment is amputation.

Yeah... I didn't feel comfortable doing this in the end either.

Seems to me it would be safe to put temporary "T" fitting the "L" or "R" port line and attach pressure gauge to see if the is any activity ... Something must be happening because only way to turn front wheels is through hydraulic pressure in ram on front axle... There is no other mechanical link up...

IF someone was in to the valve assembly before you. I would be highly suspicious of how it was "repaired"......

I like the idea of an inline 'T' fitting.

A couple of other questions if someone can help:

- Would it be fair to assume there IS flow going into the valve (Line 'P'), because all other hydraulics work on the tractor?
- Will hydraulics flow as the engine is cranking over even if not started? So...
- If I disconnected Line 'P' (from main pump), and rolled engine over but didn't start, would that confirm flow? I figure this would be safer


I did call a local supplier for Danfoss, he did confirm aside from seals and oil there are mechanical parts that can fail in these valves that Danfoss will not sell separately, meaning a new assy would be required. Also, time to arrive is almost 4 months away due to COVID. They were much cheaper than dealer however.

I am starting to suspect the orbitrol/controller/column is faulty and will require replacement however just want to be sure before I shell out the bucks. Tractor stuff is expensive.

I will keep this updated as I move along.

-Ty

 

[dmo4sho]

Were you able to get the power steering fixed? The pressure line on my gc2300 blew and after I replaced it the power steering isnt working. Wondering if you had any tips.

 

[Dmacleo]

Were you able to get the power steering fixed? The pressure line on my gc2300 blew and after I replaced it the power steering isnt working. Wondering if you had any tips.

Maybe air in system? I'll see if service manual has procedure for steering in few hours