what type if hydraulic system does my rig run? ?

[J_J]

A pump flow test will determine if the pump is putting out the advertised GPM's .

The pressure test will determine if the pump can maintain the pressure developed by the hyd component.

You need to know if the pump is performing at spec.

You need to know if the motor is using the GPM's provided.

Knowing the displacement of the hyd motor and GPM's, the motor will turn at a certain speed.

If the hyd motor is worn and bypassing fluid, it will not produced the advertised speed.

 

[CCWKen]

Most of those trenchers had an adjustable bypass or flow valve to control speed. I've rented three different styles and all had some type of ground speed control independent of the trencher chain speed. They went from creep to transport speed. The most basic was just a knob that controlled ground speed. Follow the motor circuit and see if there's a valve/diverter somewhere.

Some pumps have a valve body or gears that can be reversed to change drive direction. Running a pump in reverse usually produces little results because of the porting in the pump. Post a picture of the pump. Someone may be able to identify the type.

Here's a link to a video that show an example of changing pump drive direction on a gear pump.
https://www.youtube.com/watch?v=A8_r1tgyLgE


Here's another for a vane pump.
https://www.youtube.com/watch?v=wOqJor92r44

 

[muddstopper]

You say the pump is spinning backwards. Do you know what kind of pump you have, some of lower cost gear pumps and vane type pumps can be converted to run either direction. Usually you just need to take the caps off each end and turn the center section around. Some of the higher volume and high dollar gear pumps, have plates inside the pump that have to be swapped as well. Sometimes the plates can just be swapped and sometimes they have to be replaced with a different type, so its not just a matter of spinning the pump backwards and reversing the inlet and outlet hoses.

 

[CCWKen]

I thought that's what I just said.

 

[muddstopper]

I thought that's what I just said.

Yea, I think we where typing at the same time

 

[farm boy00]

Thanks a bunch guys! ! Can get pictures tonight. Just left for work. Talked to my dad to and we are thinking that it's the hydraulic motor. We have amazing power to the loader and even to the steering to turn the tractor. We got to talking about it and it seems like the motor is getting weak. Yesterday I was shovelling some old horse manure and was stalling hydraulic engine when scraping 2-4in of light stuff that has sat for 4-10yrs. It seems like only the hydraulic motor has a problem keeping up and stalling with light loads

 

[muddstopper]

Before you go replacing the motor, make sure it is getting the correct pressure. Its very possible that the motor could be on a separate relief than the rest of the system. You might only need to tweak that relief a bit to get where you want to be. Also as CCWKen pointed out, the motor might use a flow control to adjust speed. Check to make sure the flow control is open and the pressure is correct before replacing expensive parts.

Edited to add, you say the tractor does not have a power beyond port, you should really think about swapping the first valve out for a valve that does have PB. The way the machine is plumbed, the first valve is providing oil for travel and steering before any oil is sent to the lift and curl cyl's. If you are trying to travel and work the lift and curl at the same time, there simply isnt any oil going to the lift and curl circuit, except what ever oil is being passed thru the travel motor. Weak travel could be a sign of pressure build up on both sides of the travel circuit as the lift and curl functions are being activated. If the fluid exiting the travel motor is meeting resistance before it flows back to tank, such as the lift and curl functions, this would reduce travel speed as it restricts flow, and reduce power because of pressure equalization on both sides of the motor.