Solenoid valve problem

[Welder Dave]

Does anyone know what would cause a solenoid valve to only work one way but intermittently work the other way? Both coils are new. It was working good but now one side basically doesn't work. It's for articulating a grader.

 

[pumkinhead]

is it a double acting solenoid? do you have any photos. do you have proper power and ground at the solenoid and are there any debris caught in the orifices on the valve portion

 

[Welder Dave]

Yes it's double acting. One side works fine so it's not a ground issue. It's like the spool is stuck inside and won't move. It would have to be taken apart to check for debris. First pic. is the valve when I initially took it out without the coils. Second pic. is a similar valve for aux. hyd's. Both have new coils so it's not a coil issue. I suspect it's a problem in the stem with the plunger or something.

 

[pumkinhead]

I would pop the valves off and make sure theirs no debris and check that the plunger moves properly in the stem, maybe swap valves and see if the problem follows sides

 

[Welder Dave]

It's in an awkward place to work on and a pain to remove and put back in. I found an old parts breakdown online. I'm wondering if the stem(s) could be taken off and checked without oil spewing everywhere?

 

[pumkinhead]

im sure its going to leak,how much is hard to say but looks like it wouldn't be much. make sure pressure is of the tank and have something to plug the holes, you cold put a vacuum on the tank to slow it down and if the problem switches sides you know its that stem

 

[Welder Dave]

I just remembered, the old manual for the valve mentioned it is surrounded by oil which is supposed to give it longer life. I think I'll need to drain a bunch of oil before taking anything apart. We just got snow here so it will probably have to wait till it warms up.

 

[funwithfuel]

I would remove the magnets from the stems, polish the stems and reassemble. I've had rust pinch more than one stem. The other consideration, since you'll have em off anyway, swap em. See if it's a weak magnet.

 

[Welder Dave]

I came home and looked at the brochure and service bulletin. The valves use a wet plunger design that's supposed to give trouble free performance even in continuous duty applications. I swapped the coil with one off the other valve I'm using for the ripper and no difference but the ripper went up and down so I know the solenoid coils are good. The valves are mounted on the machine. The problem valve is in an awkward position. I might be able to take the tube/stem off but it says the spring and spring retainer may fall off. Being a wet plunger I'm thinking it will leak oil. I'll carefully read the service bulletin. I have a feeling parts might not be available but I think the O-rings are probably standard. It's strange that the valve was working fine and got intermittent and then quit earning all together. I really don't want to have the pull valve out again. Didn't hardly lose any oil at first but after sitting lost about 40 litres. I had plastic caps on the lines but I guess they can still leak over time. First I'm going to try and find an easy way to push the manual overide pin in and
maybe doing that a few times will free up the plunger and clear potential debris that is prevented the plunger from moving.

 

[funwithfuel]

Does the stem have a dimpled plunger on the end of the shaft. Some will have brass inner stem with a dimple in the center to give you something to push on to mechanically force the valve open without removing the stem from the valve body.

 

[Welder Dave]

There is about a 1/4" pin that sticks out the end of the tube assembly. It needs to push just below flush to move the spool enough to work. It needs a pretty good push. We got it to work briefly a couple times. I thought maybe if I could push it easy enough I could work it several times and potentially clear any debris that might be holding it up.

 

[funwithfuel]

Are both stems equally 'stiff ' to push in?

 

[Welder Dave]

Yes, they're both pretty stiff to push in. I'm thinking pushing the pins back and forth several times may get it working again.

 

[heymccall]

If I didn't know any better, I'd say that this stem is bent.

 

[funwithfuel]

If I didn't know any better, I'd say that this stem is bent.View attachment 297288

Great catch. Wow!

 

[Welder Dave]

That's for the aux. valve not the articulation and I did straighten it. It works fine. I straightened the stems on the art. valve as well it was working properly. Then it was intermittent and now seems to not work at all but only turning left. Turning right works fine. Something appears stuck either in the stem or the spool itself. I'm not sure if running the machine with fluid going through the valve might dislodge possible debris or if manually overriding the valve several times might do the same and/or get it working again.