wood splitter sudden loss of pressure

[jonsstihl]

My wood splitter lost pressure suddenly today while splitting wood.

splitter is hooked to a remote on my tractor but has it's own valve with it's own relief valve.

I am familiar with hydraulic systems but would like to confirm my trouble shooting steps. the cylinder does leak down somewhat when unhooked but today it leaks down noticeably faster than before.

I hooked up my in line pressure gauge and I got about 450psi but with the system dead headed the remote provides 2400psi

If I cap off the work port on the valve and apply pressure it should tell me if the valve is bad or the relief is out of adjustment.

Is there a simple way of testing the cylinder to see if it needs to be resealed. It has a little external leakage but nothing extreme no drips just wetness.

thanks

 

[BrokenTrack]

Maybe in my brain fog I am thinking wrong, but wouldn't a blown seal on the rod inside the cylinder get what you are experiencing?

You are getting 2400 psi on the pump, but not putting that work on the end of the ram because some of the "push" is blowing by the blown ram cylinder packing and going back to the return side of the pump. You would not see any leaking because it is internally leaking. That would give you your increased leak down, without seeing external leaking.

Since it happened suddenly, I would sooner thing a seal blew out on you. A plugged filter, a relief out of adjustment, and a bad valve would happen more slowly I would think. Since you got some external leakage, I would think the seal experiencing the majority of the forces, is probably now really leaking.

But I am just trying to help you work through this: I might be out of line on my thinking too.

 

[ptsg]

I'm with BrokenTrack on checking the seals.

Either that or since the splitters usually see a sudden shock after the wood splits, after so many times, it can loosen the retaining system of the piston to the rod. Usually it's either a nut or the piston threads it self on the rod. In this case, it would extend the cylinder all the way regardless if you're extending or retracting on the control valve.

 

[crazyal]

Will the cylinder move with no load on it? If so you could extend it and then remove the hydraulic lines on the cylinder and plug the one furthest from the splitting wedge. Simply pushing on the ram to try and contract it shouldn't be possible. It could be more work than just rebuilding the cylinder though.

 

[jonsstihl]

thanks guys for all the tips. my gut says this is the cylinder seal too for the same reasons you guys mentioned. plus this relief valve has a distinctive chatter that you can't miss.

this splitter is no longer made by the manufacturer and My only concern is getting this thing apart and then not being able to find the parts needed to repair. this setup is a 2 inch square trunnion setup.

I dont have a pipe wrench big enough to fit on the 4" od of the cap but there is a 1/4 inch hole in the side of the cap and looking through my scrap pile I found 1/4 inch round stock (lottery ticket time) so I already started making a tool to get the cap off.

If it holds in 450 psi of pressure I don't think I will be able to test the cylinder with air since my air only goes to 125psi.

 

[ptsg]

Any hydraulic shop should be able to provide you all the seals you need for the cylinder.

If you need help taking the thing apart, just post a couple of pictures and we will try our best to help you. Some cylinders are tricky to get the gland off.

 

[jonsstihl]

there aren't usually seals in the valve so it would have to be a catastrophic failure to suddenly not hold pressure.

 

[ptsg]

I meant for the cylinder. Should have add that to the post.

 

[s219]

Can you see or look at the fluid anywhere? My (engine-powered) splitter has a clear hose on the return line. One time when it lost force suddenly, I looked at the hose and could see foamy fluid. So I peeked in the tank and the fluid was full of bubbles. After some diagnosis, I found that the shaft seal on the pump developed a leak and was sucking air into the system. That pretty much defeated the hydraulics.

Was a good reminder/lesson for me, that air in a hydraulic system can cripple it. I am used to those obvious high pressure leaks where pressure forces fluid out, but it's the low pressure leaks which pull air in that can cause real degradation in force.

 

[jonsstihl]

ptsg, thats what I understood, I was just thinking out loud try to eliminate the valve as a suspect.

s219, hydraulic power is provided by the tractor and the loader works fine so I think that eliminates the foamy fluid but I should probably have pulled the dipstick to confirm.

I am tackling the disassembly of the cylinder today. hope I can get parts for a reasonable price.