How can I test pumop pressure without valve?

[James Eric]

I just added a loader to my Cub Cadet 1250. I have a power steering pump from a 1987 Acura Legend that is v-belt driven.

I'd like to install the pressure gauge and lines and test for maximum pressure before I get the control valves. I want to make sure that the relief valve operates within the range of the pump. The joystick valve that I like starts at 800 psi and I am not sure what the pump will deliver on the tractor.

How can I test it with out causing damage to the pump or system?

Thanks,

James

 

[Soundguy]

to test a pump , if you have a guage and a relief valve, plumb the gauge in series with the outlet of the pump and the valve, and set it tup so you can deadhead the pump THRU the relief. keep in mind many ag valves have reliefs near the 2500 psi area as that is a common ag pressure.. yet many PS pumps may be making much less.. like 300-800 psi.. and might not like pushing against a 2500psi relief

 

[James Eric]

This is what I received from the company that rebuilds the pumps.

IMP. P/S FLOW SPECS

---RPM---- : ----------PSI----:-------FLOW/PSI-----:

----------------:------------------:----------------------:

600 (+/-25): 100(+/-100):= 0.9 TO 1.4 GPM

1500(+/-25): 100(+/-100):= 1.3 TO 1.7 GPM

600 (+/-25): 600(+/-25): = 0.8 TO 1.4 GPM

2700(+/-25): 100(+/-100):= N/A GPM

600 (+/-25): 0 = 1125 TO 1275 PSI

1. Can someone tell me what this means?
I understand the column headings but I do not understand the relationships. The relief valve on the joystick controller has a minimum setting of 800 psi. 2. What happens if the pump keeps running and the valve never opens because I can not get 800 psi?

Thanks,

James

 

[RickB]

It tells me that the pump is too small and the relief is too low to be of any value powering a FEL. Find pressure and flow specs for your loader and compare them to the pump info.

 

[J_J]

A hyd system can work using any pressure and volume. A hyd pump, a controlling valve and something to use the fluid being pumped.

However, you should know that high pressure hyd can work better than low pressure and is putting more potential energy to work. Hyd volume make things work faster.

Power steering in a car/truck uses hyd to do the steering, and doesn't need much pressure or volume to work. A dump truck for instance needs large GPM's and high pressure to accomplish all that it does.

When you put a hyd system together, you have to know all the specs of all the components in the system and try to match things up such as pressure and volume.

 

[RickB]

A hyd system can work using any pressure and volume. A hyd pump, a controlling valve and something to use the fluid being pumped.

.

If the system relief pressure won't lift the load in the bucket and the flow rates are too slow to be tolerated, the assembled system is a waste of time and money. And that's where this is headed.

 

[J_J]

Best thing to do would be to get the steering valve from the 1987 Acura Legend, connect it to the pump and turn the pump at about 3600 rpm. Add a hyd gage to the PS unit, and when you hold the valve on, and the cyl is fully extended, the pressure should relieve at the end of the cyl stroke, and you can see the pressure relief setting.

When you turn the wheel in a car and hear that whining sound, that is the relief going off.

You could also go to the repair manual for that car and see how to test the PS pump.

If that pump can develop about 1500 psi, then a 2 in cyl 1 in shaft, can push with a force of 4,712 lbs, and then you have to take into account the mechanical relationship between the bucket pin to cyl mounting distance, and the loader arms to the frame distance and angle.

A test object could be a 55 gal drum filled with water, and at 8 lbs per gal, the 55 gal drum would weigh about 450 lbs plus the drum at 30 lbs = 480 lbs.

500 to 1500 relief valve.

http://www.surpluscenter.com/item.asp?item=9-6135-75-L&catname=hydraulic

 

[Egon]

It tells me that the pump is too small and the relief is too low to be of any value powering a FEL. Find pressure and flow specs for your loader and compare them to the pump info.

Sounds right to me.:thumbsup:

Looks like maximum pump pressure may be +/- 1200 psi at zero flow.

 

[James Eric]

Thanks for the comments and suggestions. Last night I did some research on pumps and pulleys. It appears I can get a pump and pulley for less than $75 from Surplus Center.

However, reading this thread am I to understand that the pressure only builds with a load? In other words, the pressure will build until the pump or system fails unless I have a relief valve set below system failure.

Thanks,

James

 

[oldnslo]

This is what I received from the company that rebuilds the pumps.

IMP. P/S FLOW SPECS

---RPM---- : ----------PSI----:-------FLOW/PSI-----:

----------------:------------------:----------------------:

600 (+/-25): 100(+/-100):= 0.9 TO 1.4 GPM

1500(+/-25): 100(+/-100):= 1.3 TO 1.7 GPM

600 (+/-25): 600(+/-25): = 0.8 TO 1.4 GPM

2700(+/-25): 100(+/-100):= N/A GPM

600 (+/-25): 0 = 1125 TO 1275 PSI

1. Can someone tell me what this means?
I understand the column headings but I do not understand the relationships. The relief valve on the joystick controller has a minimum setting of 800 psi. 2. What happens if the pump keeps running and the valve never opens because I can not get 800 psi?

Thanks,

James

James,
the way I interpret these specs is that at 1500 RPM @ 100 PSI the pump would produce 1.3 - 1.7 GPM

Bottom line of specs to me indicates relief pressure of 1125 - 1275 PSI.

Does this PS pump have the built in relief valve? It may also have a built in priority flow control. This is to keep steering speed relatively constant with varying engine RPM. That would also explain the small change in flow at 600 @ 1500 RPM.

Yes it will work for FEL, just may be slow and not have the lift you desire.

Roy