2000 Mustang 2070 Not Turning

[Cavemanj]

Greetings,

I recently purchased a 2000 Mustang 2070 with about 1500 hours. She is not in the best of shape, but the engine runs well and the hydraulics work alright. However, the right hand drive will not go forward. Left hand goes backwards and forwards no problem, and the right hand goes in reverse, just not forwards. When I push the stick, it makes a higher pitched whining noise, but there is zero movement. I swapped what I believe to be the RHS forward relief valve with the LHS reverse, but to no avail. I tried monkeying around with the hot oil shuttle valve, taking it out to make sure it has movement, but that also didn't change anything. I really need to plug the drain port and test it then, but as of now I know its not stuck. I'm not sure what the next angle of attack should be. Any thoughts would be appreciated.

Attached are some pages of the relevant section in the manual.

Thanks,
Joe

 

[Firefighter]

Assuming u bought it with this issue, does the left side and right reverse have decent power, leave the
brakes locked and try driving, u should get a strong equal resistance from the pump on the steering in both directions.
i would recommend capping the hi pressure hoses (dead heading) the pump, or if u have a pressure gauge u could check output pressures on the side that is weak, 4500-5500 Psi
if u get equal pressures or feedback in both directions, more than likely the motor needs rebuilt, possibly having a faulty teflon directional seal, or shuttle valve fault

 

[Cavemanj]

Thank you for the information, and yes I bought it with the issue. I have a 5000 psi gauge on order.

I tried putting it in park and operating. The left side moves forward and backwards slightly before I get the whining noise and no more movement. Same with the RHS reverse, but the RHS forward doesn't move at all. I'm not sure what that tells me.

When I opened the shuttle valve port, it appeared to only have a spring on that one side and not on the other, which seems like a problem to me. Aren't there supposed to be two springs, one on each side to center the valve? According to the parts manual there should be. I'm toying with the idea of cracking open the functioning motor to see what it should look like.

 

[River Fluid Power]

Thank you for the information, and yes I bought it with the issue. I have a 5000 psi gauge on order.

I tried putting it in park and operating. The left side moves forward and backwards slightly before I get the whining noise and no more movement. Same with the RHS reverse, but the RHS forward doesn't move at all. I'm not sure what that tells me.

When I opened the shuttle valve port, it appeared to only have a spring on that one side and not on the other, which seems like a problem to me. Aren't there supposed to be two springs, one on each side to center the valve? According to the parts manual there should be. I'm toying with the idea of cracking open the functioning motor to see what it should look like.

There is supposed to be a spring on both sides. The one further in only comes out from the inside when the motor is apart.

 

[Cavemanj]

Progress!

The right hand motor is not original and was replaced at some point with the upgraded LPS motor. Consequently, the machined ports for the hot oil shuttle leak off and the case drain are not identical on the left and right motors. The shuttle valve hose seems to be screwed into the correct port, but I suspected the case drain hose was incorrect, as it screws in inline with the shuttle valve. The one fuzzy diagram of the shuttle valve shows a plug here instead of the hose, and just by looking at the system it didn't make sense for there to be a leak off here. I plugged this port and sure enough I now have forward power on the righthand side. Excellent!

The issue is now I'm not sure where this hose is supposed to go. The two other available machined ports are smaller and won't accept the hose fitting. I've scoured the LPS website trying to piece it together from the pictures or the small bits of information, but no luck. Perhaps the new and improved motor is supposed to operate without the need for a case drain?

Thank you for confirming the existence of two springs, at least I can cross that out.

 

[brdgbldr]

Progress!

The right hand motor is not original and was replaced at some point with the upgraded LPS motor. Consequently, the machined ports for the hot oil shuttle leak off and the case drain are not identical on the left and right motors. The shuttle valve hose seems to be screwed into the correct port, but I suspected the case drain hose was incorrect, as it screws in inline with the shuttle valve. The one fuzzy diagram of the shuttle valve shows a plug here instead of the hose, and just by looking at the system it didn't make sense for there to be a leak off here. I plugged this port and sure enough I now have forward power on the righthand side. Excellent!

The issue is now I'm not sure where this hose is supposed to go. The two other available machined ports are smaller and won't accept the hose fitting. I've scoured the LPS website trying to piece it together from the pictures or the small bits of information, but no luck. Perhaps the new and improved motor is supposed to operate without the need for a case drain?

Thank you for confirming the existence of two springs, at least I can cross that out.

Try giving LPS a call. They have always been very helpful with questions.

 

[Firefighter]

Try giving LPS a call. They have always been very helpful with questions.

These diagrams may help u with the new motor

 

[Firefighter]

Progress!

The right hand motor is not original and was replaced at some point with the upgraded LPS motor. Consequently, the machined ports for the hot oil shuttle leak off and the case drain are not identical on the left and right motors. The shuttle valve hose seems to be screwed into the correct port, but I suspected the case drain hose was incorrect, as it screws in inline with the shuttle valve. The one fuzzy diagram of the shuttle valve shows a plug here instead of the hose, and just by looking at the system it didn't make sense for there to be a leak off here. I plugged this port and sure enough I now have forward power on the righthand side. Excellent!

The issue is now I'm not sure where this hose is supposed to go. The two other available machined ports are smaller and won't accept the hose fitting. I've scoured the LPS website trying to piece it together from the pictures or the small bits of information, but no luck. Perhaps the new and improved motor is supposed to operate without the need for a case drain?

Thank you for confirming the existence of two springs, at least I can cross that out.

These diagrams may help u

 

[Cavemanj]

These diagrams may help u

Those answer my question perfectly. Thank you.

Oddly enough, I was just on the phone with a gentleman at LPS, and he told me the the drain line should be connected right next to the shuttle valve port, which it specifically shows should be left capped in the one diagram there. I think I will follow the diagrams and just remove the drain line.