Shaver HD8 Post Driver Not Working

[jgbanshee]

I have an older Shaver HD8 post driver hooked up to a Ford 4000 that is not working. The cylinder does not want to extend on its own. If I push up helping it a bit and pull single spool valve lever back the cylinder will lift slightly, approx. a couple inches to a foot. After that when I push the single spool valve lever the other way the cylinder will not retract at all. The springs are in very good condition. Hydraulics are plumbed from tractor remote and dumps back into rear axle for return. The lines are hooked up properly. I cracked the line at the cylinder and oil squirted out when pulling lever. The post driver guides/frame are oiled generously. I took the top nut off the cylinder and removed cylinder from the driver, pulled the control lever and cylinder extended with no problem. What is left to check on this to get it working properly?

 

[JimRB]

Have you replaced the seals in the cylinder? Or at least inspected them?

 

[jgbanshee]

Have you replaced the seals in the cylinder? Or at least inspected them?

No I have not.

 

[hodge]

It's a simple system. A cylinder, a valve, and your tractor. If it's hooked up correctly, and you have sufficient hydraulic fluid in the tractor, it's very likely that it's the cylinder seals.

 

[jgbanshee]

It's a simple system. A cylinder, a valve, and your tractor. If it's hooked up correctly, and you have sufficient hydraulic fluid in the tractor, it's very likely that it's the cylinder seals.

Pulled the cylinder apart. The seal in aluminum threaded cap seem to be in okay shape but will probably replace while doing this. The rod guide lock nut at other end was loose and guide is able to spin. Will this create the problem Im having? There are no other seals I could find. Does the rod guide act as some sort of gland to push the rod out as well as a guide?

 

[Bkeys1932]

how lose was the nut? So I have the same driver you do, the piston by the nut is supposed to be able to turn. I learnt that the hard way when I rebuilt mine the first time it will not function properly if the piston nut is tight piston has to rotate slightly. So that’s normal for that specific cylinder. I’d try a different tractor if possible or try your ford 4000 on a different hydraulic implement. That will quickly help you eliminate if it’s driver or tractor. Also if cylinder is out hook hoses up with cylinder unhooked free just to eliminate any binding. I know mine will bind at times with no clear reason why.