Need help rebuild little control valve

[lhfarm]

We have a Newgren lift on our 49 Willys CJ3a. It provides hydraulic lift for standard 3pt implements. We were testing a new pump (another posting coming) and the control valve stuck. Couldn't lift. I took the lift off the jeep (it sits under the rear cargo area) and removed the control valve. It appears the return side plunger is sticking. I don't have a good (operative word) hydraulic repair shop within an hours drive, so I'd like to rebuild the valve with your help. I'm a rookie and there is no known documentation (other than installation instructions) for the lift and valve. So I'm hoping that with some photos someone (or many) might step me through the process.

The lift off the jeep is in the first picture. The "L" shaped control sets on top of the reservoir. The leg bolted to the control is moved by two rods. The top rod goes to the rear of the unit and jeep and the second rod is next to the drives seat. Pushing forward on that raises the lift, pushing back lowers it (gravity).

The next photo shows how the control sets on the reservoir. The next pictures show the "return" side (fluid back to the reservoir) plunger in the "out" and "in" position. I can move the plunger with my finger, but it doesn't move as easily as I think it should.

I'll post additional pictures.

 

[kennyd]

You could try removing the spool and polishing it with some #0000 steel wool and diesel fuel.

 

[lhfarm]

The first two pictures show the plunger operation on the pump input side. This plunger moves easily. The third shot is of the output to the ram. Beneath the screw (head visible on the fist two shots) is a steel ball.

I'm not familiar with control valves, so not sure what to expect when I start to disassemble. Should I be looking for "O" rings or seals? I may have to fabricate those or find something that will work.

How should I proceed? Just take the control lever apart so the plungers can be removed?
Any and all advice appreciated.

Thanks,

 

[lhfarm]

You could try removing the spool and polishing it with some #0000 steel wool and diesel fuel.

It would probably help if I had the right terms. Which part is the spool? Is there a general description of a valve around that might help me understand how this works?

Thanks,

 

[kennyd]

The "spool" is the part of the valve that slides in and out to direct the fluid flow. User AKKAMAAN has posted some great detailed pictures recently, search his post's.

 

[lhfarm]

The "spool" is the part of the valve that slides in and out to direct the fluid flow. User AKKAMAAN has posted some great detailed pictures recently, search his post's.

Wow, that lead to a morning's worth of reading! I sure have a lot to learn.

We are trying to keep the lift original. Had the cylinder totally rebuild, which meant a new body. The crank driven pump is NOS, but leaking. I'm hoping the valve is not completely worn out and can be renewed with a cleaning and new seals or O-rings.

The pump has no identification markings, other than Patent Pending and an "S" on the body. I'm trying to find some documentation of the pump size and flow, but no luck. The lift was most likely made in the late 1940s or early 50s.

I think I'll try to disassemble it to the point I can remove the spools, taking pictures along the way.

Thanks for the information.

 

[lhfarm]

Here is the disassembled valve. I can't find anything that looks like a seal. Is it possible that none were used? What should I use to clean the entire unit? Diesel was mentioned earlier. Should I use air to blow the dirt from the body?

Sorry for the brightness of some of the photos.

Thanks,

 

[beenthere]

Looks like you are making progress. And good pics too.

A good polish of the inside parts with close tolerances (try not to change them) would be recommended. I'd be careful with blowing things around inside the body but get it clean. Bothers me to see inside parts lying there with the 'outside' dirt. But I'm **** about that.

 

[lhfarm]

Looks like you are making progress. And good pics too.

A good polish of the inside parts with close tolerances (try not to change them) would be recommended. I'd be careful with blowing things around inside the body but get it clean. Bothers me to see inside parts lying there with the 'outside' dirt. But I'm **** about that.

My mistake. I did move them to their own storage bag as soon as I took the pictures.

This thing is really small. I'm wondering how I should clean the inside. Don't know if a Q-tip dipped in diesel will leave residue. You can see in the fourth picture that both spools have very small ends. I haven't been able to see well enough inside the housing to determine what I'm dealing with. Next step is cleaning.

 

[wdchyd]

I'm wondering how I should clean the inside.

Carb Spray from Wallyworld (or AutoParts Store)