Bad PTO Solenoid?

[SpringHollow]

My PT1850 PTO circuit is not working (does not turn the bush hog). Checked the voltage at the valve and it gets 12V when the pto switch is on (goes to 0 V like it should if you try to start the tractor). Checked with a clamp-on DC amp meter and both the positive and negative wires show about 3 amps. No clicking sounds when you turn the switch on and off. Sound like a bad solenoid? It seemed to magnetize though - piece of metal seemed to stick to it - I will have to check that more carefully.

Ken

 

[ponytug]

From other posts, it sounds as if the solenoid is very touchy about torque, and I presume, alignment. When I spoke to Terry at one point, he mentioned to correct torque on the nut, which was tiny 8-10ft-lbs, but don't quote me. You might also check to ensure that the valve is clean internally.

All the best,

Peter

My PT1850 PTO circuit is not working (does not turn the bush hog). Checked the voltage at the valve and it gets 12V when the pto switch is on (goes to 0 V like it should if you try to start the tractor). Checked with a clamp-on DC amp meter and both the positive and negative wires show about 3 amps. No clicking sounds when you turn the switch on and off. Sound like a bad solenoid? It seemed to magnetize though - piece of metal seemed to stick to it - I will have to check that more carefully.

Ken

 

[SpringHollow]

Well, it magnetizes the end, so i have to yank the valve and see how dirty it is.

Hi Peter, yes the nut says 10 ft lbs

Ken

 

[Bob999]

My PT1850 PTO circuit is not working (does not turn the bush hog). Checked the voltage at the valve and it gets 12V when the pto switch is on (goes to 0 V like it should if you try to start the tractor). Checked with a clamp-on DC amp meter and both the positive and negative wires show about 3 amps. No clicking sounds when you turn the switch on and off. Sound like a bad solenoid? It seemed to magnetize though - piece of metal seemed to stick to it - I will have to check that more carefully.

Ken

For some significant period PT was overtorqueing the nut on the PTO solenoid and it caused quite a few failures of the valve--overtorqueing elongates the valve body/solenoid and causes it to bind. It happened to me and was impossible to diagnose by inspecting the valve--it still moved when the PTO was actuated and I could not detect a visible difference in the movement between the replacement which worked and the one that didn't. Terry required me to rule out all other possible causes--a lengthy and fairly arduous process-- before sending out a replacement valve.

The fact that you cannot hear a click when it is actuated suggests that you may find something in the valve preventing it from operating properly rather than a bad solenoid.

 

[SpringHollow]

I think my valve only has 3 - 4 hrs on it at most. I am pretty sure it was replaced at the factory but I can check. I have not used the PTO in over a year. Tearing it apart might help determine what is wrong.

Ken

 

[Marks481]

Terry required me to rule out all other possible causes--a lengthy and fairly arduous process-- before sending out a replacement valve.

Thanks for being the guinea pig. When my PT422 arrived with the PTO dead on arrival in June 2005, he wouldn't even let me finish describing the symptoms... just told me flat out what the issue was and sent me a new solenoid. I

Maybe he had just finished up the long troubleshooting process with you....

Here is the link to my thread on PTO problems:
http://www.tractorbynet.com/forums/power-trac/60509-my-power-take-off-doesnt.html

 

[Wayne County Hose]

Ken,

You can also remove the coil and the valve, put the coil across a 12v battery and watch it operate. It should be real snappy, if you know what I mean. No sluggishness. I have seen these valves have a little piece of gank holding them up. Just stick a little pick or tiny screwdriver in there to move the plunger and blow it out with air if that's the case. If your coil is magnetized, you just verified that the electrical circuit is fine.

 

[Bob999]

Thanks for being the guinea pig. When my PT422 arrived with the PTO dead on arrival in June 2005, he wouldn't even let me finish describing the symptoms... just told me flat out what the issue was and sent me a new solenoid.

I would like to accept the credit but my problem happened in 2007 and occured with 180 hours on the machine--most of it using the PTO.

 

[Bob999]

Ken,

You can also remove the coil and the valve, put the coil across a 12v battery and watch it operate. It should be real snappy, if you know what I mean. No sluggishness. I have seen these valves have a little piece of gank holding them up. Just stick a little pick or tiny screwdriver in there to move the plunger and blow it out with air if that's the case. If your coil is magnetized, you just verified that the electrical circuit is fine.

I think the advice to remove the valve and operate it where you can observe the action is good. However I will repeat the caution that I was unable to observe a difference in the operation of the failed valve and the replacement valve--both moved the same distance and the "snap" of the movement seemed to be the same.

 

[SpringHollow]

I do not think I can purge the circuit after putting the valve back in - is that ok?

And I assume I just take the solenoid off and then loosen the hex at the base of the shaft where the block is?

Ken