Gresen 550

[VAFarmer6]

I have a 1967 Oliver 550. It has a front end loader that uses one way cylinders on each side of the tractor to lift the bucket and a pull cable to dump the bucket, about as simple a setup as you can get. One hose from the bottom of each cylinder leads to a controller marked "Greson 550". The only other markings there are "8/12/68" which I assume is the year it was manufactured. Looking at the controller handle, the lower left side has a port labeled IN and the lower right side is marked OUT. Hoses in and out of these ports lead to the tractor's hydraulic sump. Each of the two hoses from the cylinders lead to a separate port on the top of the contoller. This setup/system lifts huge loads very quickly without any jerking or binding of any sort when you pull the lever...and when you push the lever, the bucket goes down, but slower than it seems like it should...and much much slower that it does if you turn the tractor off and then push the lever in. A friend says it is plumbed wrong and both hoses should be plumbed through a T fitting to only one of the ports on top and NOT one hose to each of the top ports as it is now. He is convinced it is magic that it works at all plumbed like it is. I can find no information on a Greson 550...am wondering if maybe it is a Greson made specfically for the Oliver 550????? Anyone familar with this controller and how it should be plumbed to handle two one way cylinders? Thanks for any help.

 

[J_J]

Perhaps some pictures might help ID the valve.

Do you want a new valve?

You can do the same thing with a single spool, single action valve, or a DA single spool valve , with the A work port plugged.

 

[VAFarmer6]

Perhaps some pictures might help ID the valve.

Do you want a new valve?

You can do the same thing with a single spool, single action valve, or a DA single spool valve , with the A work port plugged.

Loader lifts fine...and would like to keep it as stock as I can and still use it.....really does go down slower than I think it should though...NOt sure if problem is it is plumbed wrong or that a 45 year old valve needs new rubber/springs/cleaning out????? Would it hurt anything if I hooked both hoses to a T and tried it out using one top port and plugging the other and the reversing the two to see if one worked better than the other????
Hope I figured out how to upload the pictures, please bear with me, here....

 

[J_J]

It appears that that is a DA hyd vale and they are using it in a SA cyl configuration.

I don't know your hyd pressure, but you should be using hyd fitting instead of the water pipe fittings.

The one pressure work port should be be going to a tee which will go to each cyl.

If the QD is in the return flow, it might be slowing things down.

When your cyl are lifting, you provide flow to the SA cyl, and when you lower, the flow flows back through the same line to the other work port and to tank.

The flow from the cyl should be at very little pressure, and pass through the return line uninterrupted.

When the valve is in neutral, the flow goes in the IN port and through the OUT port to tank.

Where is the pull valve you mentioned?

 

[VAFarmer6]

Service Manual says system operates at 1500 psi.....add 45 years to that and it is probably still high enough I should get rid of the water pipe...some of those fitting may well be 45 years old as well.

Pull valve??? I was talking about pulling and pushing the lever on the controller...don't remember/see anything about a pull valve. Not sure I understand the DA, SA, QD terms, but understand you agree with my friend that is should have a tee on one port as opposed to having each cylinder hose being attached to its own port. Would it make any difference if I used the port closest or the furthest from the handle...would experimenting to see if one worked better than the other potentially hurt anything?

 

[J_J]

Both cyl should be connected to the same port.

You said pull cable. What is the pull cable pulling on.

The way most double action valves are used with a single action cyl, is when you push the lever, you cause fluid to flow to the cyl base end, raising the loader.

When you pull the lever, the other work port will allow the fluid to flow to tank.

What some people do is plug the A work port and only use the B work port to raise and lower the loader.

When you use the valve like this, you cause fluid to flow out the B work port to raise, and when you pull the lever back, the B work port dumps the fluid to tank.

Fluid should be going to both cyl at the same time. One hose from one work port going to a tee and then to each cyl.

QD = quick disconnect

 

[Leejohn]

Are you 100% sure the pressure line is pressure from the tractor? The reason I ask is most of the time the return is low on the sump. Make sure there isn't pressure on both lines, if there is only one hose getting pressure the loader would be tristing real bad with any load at all. The cyls plumbing has to be changed.

 

[J_J]

Go ahead and connect the two cyl to a TEE and run the one line back to the B work port.

Run the other work port to tank.

If you want to find out which line is the pressure line, remove both lines from the valve and place in a bucket. Start tractor and you will see which one has flow.

Where is the QD line going?

 

[J_J]

Go ahead and connect the two cyl to a TEE and run the one line back to the B work port.

Run the other work port to tank.

 

[oldnslo]

If the loader is lifting correctly you have pressure going to both cylinders so it would make me question why it would require plumbing changes. With a normal DA valve spool only one cylinder would be getting pressurized and the loader would only lift with one cylinder causing it to twist like leejohn stated.

Gresen did make some some oddball and or special valves. It is possible this is one of them. To check the valve function will require removing the hoses from the valve and them determining flow path with valve handle pulled and pushed.