Woodtractor1
Member
Hi,
I have a 1978 omc mustang 770 loader that barely creeps up the slightest incline or up a small curb.
I just replaced the Ford 172 diesel engine with a Ford 172 gas engine.
I drained the hydraulic fluid amd replaced with tractor hydraulic fluid from the local hardware store. I didn't replace the filter at this time. I couldn't find one. Went to 5 stores today and ended up with a part number and a special order that will be here in a week. The current filter looks relatively clean.
The power was lacking before the engine swap but not nearly as bad as now. I ordered a replacement filter and will do another hydraulic oil change next week. The vacuum gauge sits somewhere around 2 when warm to 5 when cold, so not very high from what I understand.
The loader has a series 23 sundstrandt hydrostatic motor and similarly looking sundstrandt hydrostatic pump but I haven't laid eyes on the pump nameplate for the model.
1. How do I troubleshoot whether it's the engine's clutch, the hydrostatic pump,or the hydrostatic motor.?
The engine revs high and does not bog or stall when I am trying to go over a small bump or incline, but there's just no power. It will make it if I back up and get momentum. Engine oil pressure is 45-50. All my other hydraulic functions seem to have plenty of power.
2. If I need to install gauges where would I install a pressure gauge to the sundstrandt pump or motor?
3. Do I need to bleed the system? How do I do that?
I drove the 770 for a week and still had the same symptoms.
Thanks so much!
I have a 1978 omc mustang 770 loader that barely creeps up the slightest incline or up a small curb.
I just replaced the Ford 172 diesel engine with a Ford 172 gas engine.
I drained the hydraulic fluid amd replaced with tractor hydraulic fluid from the local hardware store. I didn't replace the filter at this time. I couldn't find one. Went to 5 stores today and ended up with a part number and a special order that will be here in a week. The current filter looks relatively clean.
The power was lacking before the engine swap but not nearly as bad as now. I ordered a replacement filter and will do another hydraulic oil change next week. The vacuum gauge sits somewhere around 2 when warm to 5 when cold, so not very high from what I understand.
The loader has a series 23 sundstrandt hydrostatic motor and similarly looking sundstrandt hydrostatic pump but I haven't laid eyes on the pump nameplate for the model.
1. How do I troubleshoot whether it's the engine's clutch, the hydrostatic pump,or the hydrostatic motor.?
The engine revs high and does not bog or stall when I am trying to go over a small bump or incline, but there's just no power. It will make it if I back up and get momentum. Engine oil pressure is 45-50. All my other hydraulic functions seem to have plenty of power.
2. If I need to install gauges where would I install a pressure gauge to the sundstrandt pump or motor?
3. Do I need to bleed the system? How do I do that?
I drove the 770 for a week and still had the same symptoms.
Thanks so much!