View Full Version : pump or wheel motor?

02-02-2008, 06:09 PM
Is there any way to determine whether I have a bad pump or a bad wheel motor on my old Scag stz52?

02-02-2008, 07:12 PM
The proper way would be to take it to a dealer and have them perform a pressure test on the system.

The only other way I know of is swap the wheel motors from one side to the other and see if the problem changes to the other side.

02-02-2008, 08:55 PM
Is there any way to determine whether I have a bad pump or a bad wheel motor on my old Scag stz52?

Yes tis will cost you about $60 but it will let you know

02-02-2008, 09:15 PM
Thanks a lot

02-02-2008, 09:56 PM
Any hydro leaks? When my pump went bad it leaked excessively. :cry:

Correct me if I'm wrong but don't pumps go up more often than wheel motors.

02-02-2008, 10:01 PM
When you have a problem like this. cross the lines from one pump to the other. you will pin point the problem rapidly.:drinkup:

02-02-2008, 11:14 PM
When you have a problem like this. cross the lines from one pump to the other. you will pin point the problem rapidly.:drinkup:

That's a good idea.

02-02-2008, 11:14 PM
Well chew on this before you go moving wheel motors. Most manufactures with pumps and wheel motors are separate systems meaning the left side cannot contaminate the right side and vise a versa when there is a failure.
What if your pump grenades and is sending metal down into your wheel motor causing both to go bad and now you take your good wheel motor and stick it inline with your bad pump to test and you now send the cr@p from the pump into the good wheel motor.
Bite the bullet and take it to a reputable dealer who can pressure test your system and get you back up and making money.

02-02-2008, 11:16 PM
How do you pressure test the pump an motor?

02-02-2008, 11:23 PM
Your right MM,
I felt a little funny when typing that part but for some reason it didn't soak in till you mentioned it. :hammerhead:

Guess I owe ya one http://www.xtremesystems.org/forums/images/smilies/thumbsup.gif

02-02-2008, 11:37 PM
I found this link online once before think it still works, pages 8 through 10 are the test procedures.
and that is the proper test tool averages $200-$300 for the tool.

And you test just the pump, if it works your wheel motor is bad:hammerhead:
if you test the pump and it fails then you pull it and tear down and check for excess material that may have traveled and contaminated the wheel motor

02-02-2008, 11:40 PM
Guess I owe ya one http://www.xtremesystems.org/forums/images/smilies/thumbsup.gif

No Prob Rob, I got your back buddy:drinkup:

02-03-2008, 01:12 AM
Simple check of the motors. Jack up the mower and turn the wheel by hand. If it turns easy, likely the motor is gone. And while it is true that most times one pump going out won't kill both motors. It does in rare cases. Any system that shares a return line from the motors to the reservior can have it happen. Most makes have 2 lines ( 1 for each side ) for returns and it takes a bad filter to contaminate both.

02-05-2008, 01:36 PM
A flow meter test will tell you if it is the pump or the motor. The stall test using the flow meter will tell you if you have a bad wheel motor. In short.....you have the meter hooked up and stall the machine...like against a tree or unmovable object as the brakes are not strong enough for this test...If a leak down reading is show of more than .07 gal...the motor is shot. Don't cross run hydro hoses as it was mentioned before you will contaminate the good motor. A good flow meter and knowing how to use it will take the guess work out of hydro troubleshooting.

02-05-2008, 01:52 PM
From manual....
Initial wheel motor test.
1. A good wheel motor should turn hard in forward. With unit jacked up and jack stands under unit, grab the tire and try to rotate it forward.
2. A good wheel motor should not turn in reverse.
3. If the wheel motor turns easily and or clicks while turning, the wheel motor may have internal damage.

Wheel motor stall test.

1. To check wheel motor leak through, install a bi-directional flowmeter at the inlet port of each wheel motor.
2. With flowmeter plumbed in, put the machine up against a solid object. Run the engine at full throttle.
3. Move the drive handle in the forward direction. Watch the pressure gauge on the flowmeter, when it reaches 3000psi, read the flowmeter. There should be no more than .5gpm registered. This is the allowable limit.
4. Rotate wheel 45 degrees and repeat test. Repeat this process eight times for each wheel.

You need to test the pump first to make sure you have a viable pump to do this test. Hydro system temp also needs to be at normal operating temp....from 160 - 210 degrees.

This is just a sample of one of the testing procedures...each pump and wheel motor mfg has their own procedure.

Hope this helps.