Log splitter ram creeps forward.

[sqdqo]

I have an older hydraulic log splitter where the ram inches forward on it's own. It's a problem when you are lifting a heavy log on to the splitter and the ram has moved forward and is now in the way. I thought it was the valve getting worn and fluid leaking internally so I replaced the valve. Nothing has changed, it still moves forward on it's own. This cylinder powers both forward and backward. Could there be some sort of leaking fluid inside the cylinder?

 

[J_J]

Using logic, the ram should not move when the valve is in neutral. The only thing I could think of is maybe air in the ram. When the return lever is kicked back to neutral, this is done with pressure, so if air were trapped inside the cylinder, since it is now under pressure, the cylinder might move. I don't think it would move a whole lot. Does the ram move any after shutdown? That would tell you if maybe air was causing this.

Even new valves leak to some degree, perhaps this one does.

If the kickback does not put the valve exactly in neutral, it could leak some.

Do this. Remove the hose from the bottom part of the ram. Note if any fluid or air escapes. Place the end of the hose in a clean bucket, and start the splitter. Don't touch the valve lever. You should only see fluid that was in the hose. Let the splitter run for 10 min, and the amount of fluid in the bucket will provide you with the answer.

In neutral, the fluid just travels in a loop, not doing any work. So if the ram is moving, there is a force behind it, leakage or air pressure.

 

[sizzami]

I agree w/jj the problem is almost certainly air check the fittings on the return end too they may be drawing in air .

 

[J_J]

Check the fluid level, and the suction line. If the suction side draws in air, it will add a good bit of volume to the fluid, and you can compress air, so as air tries to come out of suspension, it will expand. When the log splitter valve goes back to neutral, the work ports are closed off, so any air in the system will expand and possibly move the cyl..

 

[AKKAMAAN]

I have an older hydraulic log splitter where the ram inches forward on it's own. It's a problem when you are lifting a heavy log on to the splitter and the ram has moved forward and is now in the way. I thought it was the valve getting worn and fluid leaking internally so I replaced the valve. Nothing has changed, it still moves forward on it's own. This cylinder powers both forward and backward. Could there be some sort of leaking fluid inside the cylinder?

You said it was an OLD splitter??!!! Worned Warning!!!

Make sure that the control valve really goes back to NEUTRAL....If the springs, that center the spool, are going bad, spool can stay off center in neutral....and cause movement

Does the cylinder move when pump is shut down??
How fast is that piston moving?....inches per minute?...
Does it keep on moving to the end of stroke?....
What size is the cylinder? Bore diam?...Rod diam?

Answers on these questions can tell if air in the system is an realistic cause or not........trapped air under pressure cant keep moving a cylinder "for ever"....and something have to come out from rod side....air in oil usually dont come out at the low point....

If air is out of the picture..... then I think it is oil pressure from returnline in combination with a worned out spool valve, that causes this.....resistans in control valve, kinked lines, fittings and a clogged filter etc.....that can easy cause a 15-20+ psi pressure....if control valve is old and worned, this "pressure" can creep into ports and start the movement.....it only need leekage into capped side port in spool valve, if piston seal is bad....15-20 psi can easily overcome break out friction and the piston will move.

 

[J_J]

He said he installed a new valve.

 

[AKKAMAAN]

He said he installed a new valve.

Woops ....Alzh*)()(*&(&^ers kicked in again...sorry....

well check the Piston seal then....extend to end....then disconnect rod side hose on the valve.....plug valve port and put hose in the bucket....all like JJ said....BUT then hold control valve on extend at end of stroke for a few seconds (by pass thru releif valve is max pressure)....slow dripping "can" be OK, but pouring is bad....if piston seal is bad, then also check the rod seal....retract and the disconnect capped side hose....plug vale and capped side hose.....hold retract for a few sec's and check for leak thru rod seal...


If rod seal is GREAT (no leak at all) .....only rebuild with a new piston seal....check out piston rod for straightness and divots before replacing a bad rod seal kit....