Top Link Hydraulic Cylinder Woes

[Industrial Toys]

This is the rake that I am having trouble with. I used an old 2-1/2" top link cylinder that I had built almost twenty years ago for my little JD 770. It would not stay put, either extending or retracting on it's own. I figured the cylinder was not up to the task and FINALLY got a new 4" custom made link from the guys that make cylinders for Wallenstein.



Alas, the new cylinder does the same thing, but not as bad, plus I have much better/slower control. It mostly happens (on both cylinders) when the load on the cylinder changes from pulling to pushing or the other way around, but MORE when changing to pushing in.

But it's not a constant issue, leading me to believe, it's not the AUX valves that are leaking. It's like it has air in it, but there should be none left in there. The cylinder ports are on top and the cylinder has been cycled quite a few times.

 

[Spanner]

It would not stay put, either extending or retracting on it's own.
...
Alas, the new cylinder does the same thing, but not as bad, plus I have much better/slower control. It mostly happens (on both cylinders) when the load on the cylinder changes from pulling to pushing or the other way around, but MORE when changing to pushing in.
.

Cylinders do not self-energise. they are slaves to a control input from somewhere.

To make a ram extend it must get oil from a control valve upstream. A double-acting ram will need oil from either direction to make it move.

A single-acting ram needs oil to extend and pressure from gravity on a weight/load to move the other way when a valve is opened.

On this basis it seems to me you have a faulty control valve. SCV.

I see your welder (V.nice) Did you make the Roll Frame?

 

[Industrial Toys]

It's the force of gravity either pushing or pulling on the Ram that makes it move depending on 3PH position. I notice it most when parking it. Drop the rear trailing wheels to the ground, lower the 3ph arms and then you see the top link cylinder press in a couple of inches.

It does make me start to re-question why some top links have the check valves and most do not. No one has been able to answer that to my satisfaction.

Needless to say, this has been disappointing.

The welder frame I got at auction with the welder. I modified it slightly and mounted my plasma underneith to make it more handy, and less prone to growing legs. Both are on a single power plug. The total affair is quite handy, if not possibly dangerous for tipping! I'm surprised a large company allowed that.

 

[Spanner]

Welder trolley is v.nice. - I meant the frame on the tractor.

Suggest you try the ram on another tractor and confirm the issue?

 

[Industrial Toys]

That's actually a piece of junk I bought cheap at a Richie auction. Then, modified it slightly in width.

I hate 3ph implements but this makes it bearable.

 

[Spanner]

I see that.
No, I was referring to the OPS (It's not ROPS?) frame on the tractor in Pic 1. Hinged with beacon.

 

[MtnViewRanch]

Do yourself a favor and get 2 restrictors that are .060. One for each line. This should take care of your problem.

 

[Industrial Toys]

Thanks. But please elaborate. What is causing the "squish" if you like. And what of the check valves?

 

[ovrszd]

I've had this problem for several years.

Restrictors slow the movement of the cylinder. Did nothing to change my issue.

Following to see if a fix appears.

 

[Industrial Toys]

I will try reversing hoses in case one (valve) side only is leaking.

I may try a different SCV although that is difficult as there is a toggle switch atop one SCV lever to control the electric valve on the rake.

I noticed that the rake angle doesn't always stay where put and always figured it was oil getting around the (worn) seals, but maybe I have another issue going on. It's a closed hydraulic system.

Another thought. I have problems with Air getting into the single acting hoist cylinder of my dump trailer. Maybe there is an issue with the tractor. It gets worse when things warm up.