PowR Kraft 4 Ton Electric some jitter, loss of power

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Jerry_NJ

Minister of Fire
Apr 19, 2008
1,056
New Jersey USA
I got my 4 ton PowR Krart out today to split some green Ash rounds that were about 16" in diameter and 16" long, very heavy I'll guess 50 pounds or more.

For the first time I was using the splitter on a 50 12 Ga extension cord.

First problem, the splitter stalled on the first split with the splitting wedge going in no further than 1/2" (estimate, I used a sledge to knock the round free). Then I noticed the hydraulic ram had some "jitter" when it was moving toward the split, as well as when it was retracting. I don't recall if that is normal, anyone else notice the a jitter?

While the spits are larger than the size limit specified for the splitter I was surprised it didn't do better, even split the round.

I have used only on softer rounds, Birch and White Pine, and some smaller hard wood pieces, and in the past I always the splitter plugged directly into the house electric outlet. Would a 50' 12 ga extension cord cause enough power drop to be noticeable? I believe 12 Ga is recommended for extensions up to 50'.

I am running on the original hydraulic fluid, and estimate it has no more than 25 hours run time on it.
 
Have you check hydro level?
 
Yes, but the fluid is so clear it is hard for my (old) eyes to see. It looked to be 3/4th of the way up the rod between the top/bottom groves running around the dip stick.. a rather simple dip stick...just a rod.

I assume it takes the same hydraulic fluid as a auto floor jack or an air compressor.

Do you think low fluid would cause ram jitter I mention? I don't use the splitter often and my memory isn't great, but I think the jitter is new.
 
If it didn't get super hot and blow a breaker I would bet big on low hydro fluid.......;)
 
The owner's manual is available online, at the PowR'Kraft site, and gives you the exact specs for the oil. I use a 25' 10 gauge cord on my 7-ton. I don't know what the manual specifies for the 4-ton. I will say that splitting fresh-cut wood generally seems easier than bucked wood that's been lying around for months. Also, I have better luck with the wedge going in a fresh-cut end than one that's weathered, even if the wood has been sitting out for months.
 
Wow, I see in the manual the 4 ton holds almost a gallon of hydraulic fluid. It calls for a change of oil at 100 hours, I think my unit is less than half that amount of run time.

The manual also suggests bleeding the system and that air in the loop could cause the problems I am asking about. Unfortunately the manual either doesn't show of I can't find the bleed valve. I assume it is the "wing nut" next to the dip stick that is left a turn or two open when the unit is being used... that should cause an automatic "bleeding" of air, or is the bleeder vallve somewhere else?
 
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I would add some fluid ,then Bleed it ,as per manual instructions cuz it can't hurt and may be all U need to do
With My 7 ton, U stand it up, remove the dip stick and cycle it a few times ,to bleed it
If it's jerking, extend the ram, hurry up !! and smear some grease on the the ram, and be sure the other rods are lined up right and not twisted,
hope the last part makes sense
 
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Thanks, I figured just operating requires that a valve be opened (closed for movement to prevent leaks), so that couldn't be the bleeder (or removing the fill/check rod), but operating the unit in the vertical position could make The difference.

As for adding oil I wonder about comparability. I'll look again but I recall the manual (downloaded yesterday) give a list of satisfactory oils and then said not to mix.
 
Cycling the system a few times should really eliminate any air in the system unless you are introducing new air. Low hydro fluid will also cause the stuff you are reporting (and can introduce air). One question - do you hear a change in motor tone when the ram jerks? Like the pump picks up oil (primes) and then looses the prime?
 
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I'll listen when I start again, not splitting today, but I have several large (for me and my small splitter) Ash rounds yet to split. The three rounds and some other small stuff I split yesterday were first split with a maul/wedge then the 4T splitter split the pieces easily. This in effect cycled the system at least 15 or 20 times, but I will look to adding some oil at least do a better job checking the level.

I found in the manual on start up of use:
4. Before starting the splitting operation, cycle pressure plate of the log splitter three to four times back and forth by pushing and releasing switches, to help remove any air
that may have mixed into the hydraulic fluid during handling, storage, etc. Always warm up the unit before use during cold weather by cycling 4 -5 times more.

That said, it must auto bleed. I will confess I used it a few times last time without the bleeder valve open. Not sure if that causes any damage or problems. I just forgot.

I also wonder it the rounds will split easier if they are allowed to dry/season for a month or two before splitting.
 
My electric splitter has 2 support rods running up the sides. I had the jitters once when the nuts worked loose on the end of one of them.

Good point. Check your manual to see if there is any lube requirements for anything that moves.
 
I've read on this site (but have no personal knowledge) that operating the splitter with the bleed valve closed can cause blown seals. I don't know what symptoms that would produce.
 
I've read on this site (but have no personal knowledge) that operating the splitter with the bleed valve closed can cause blown seals. I don't know what symptoms that would produce.

External seal = leaks
Internal seal = loss of pressure (power).
 
Thanks, lots to think about and check. I know I have operated with the bleeder valve closed. I just forgot which way it should be and "logic" told me it should be closed. After running a few splits, I'll guess not more than 10, I check and leaned the closed position if for transport, not for operation. Still, the unit has worked fine until yesterday. But I suppose the operating error could have damaged a seal that didn't fail immediately. Still lots to check and I plan to sharpen the splitting wedge/end tool My recent experience with Fisker splitting axe showed me the value of having the splitting edge sharp.

Still wonder about mixing fluids, the Pow R Kraft lists a number of hydraulic fluids but doesn't tell what is in the factory unit.

My unit has two round rods on either side of the ram, and there is a handle on the "top" end, but must be some bolts holding it all together. I'll also look at adding some light grease to those rods.

I think I read a consensus that the ram should not Jitter when moving in either direction. Mine does in both directions suggesting it something to do with a sliding surface not with the hydraulic pump.
 
I also wonder it the rounds will split easier if they are allowed to dry/season for a month or two before splitting.

Yeah with those size rounds let'em dry out a little for sure. I have the exact same splitter but only use it for re-splits during burning season. I will try to remember to plug it into a 50' 12 gauge and see what happens. Shouldn't make a difference.
 
On my 7-ton, the nuts securing the rods are on the handle (the silver ones, on the right of the black handle). P1020057 (1024x575).jpg
 
Went out to check out the great inputs.

Hydraulic oil looks okay, about midway between the upper/lower rings marked on the rod.
Found one of the 21 mm nuts on the back side of the handle loose, and the other not real tight. Thanks Maple 1. This may be the jitter issue. I would not have checked those as looking at the handle and seeing the two stop washer (plastic nut inserts) nuts on the top I figure all is tight. but I shook it by hand and felt some play, looking underneath (splitter sitting on its back end in a vertical position) I found two "stop" nuts and one was at least a turn loose. The other not so loose but I got a half turn on it with a wrench.

I'll have to power up to see what those rods do, they must travel along with the ram to balance it on the two sides. The piston is inside the center housing and looks bright and oiled just looking at the 1/2" or so that sticks out the end when the ram is in the home position.

This doesn't answer the power problem, and that may be simply the 4 ton can't split green Ash in a 16" diameter. The manual states limit is 12". I believe Ash is one of the harder (and better) fire woods.
 
The rods are for re-enforcing strength, I believe. (That likely wasn't the right terminology but anyway).

If the nuts on them get loose then the rods get sloppy and things can get out of alignment with back & forth movement which can cause the jitters.

Easy to check - just see if you can move either the rods or the nuts, by hand. Any looseness or wiggling means get a couple wrenches & tighten the nuts - while holding things straight. Not rocket surgery by any means - I could temporarily get rid of the jitters just by hand tightening the nuts 'for now' until I dug a wrench out.

I've got a 4 ton but it's a different make - post a pic of yours if you can.

EDIT: Ooops, sorry, missed your last post.

EDIT AGAIN: Dirt & woodchips etc in around your beam/rods/moving parts can also contribute to jittering.
 
Here's a picture, I'd sure like the larger wheels I see on the recent model. PowRKraft.jpg

I am yet to give it a try following the tightening of the nuts on the rods, the RH one was very loose - RH looking down at the handle.
 
Here's a picture, I'd sure like the larger wheels I see on the recent model. View attachment 107163

I am yet to give it a try following the tightening of the nuts on the rods, the RH one was very loose - RH looking down at the handle.

The two rods pull the ram (and thus the log) toward the splitting wedge. All of the hydraulic force is transmitted through those two rods, so if they're not equally tight, they'll be pulling at an angle to each other. Seems to me that could certainly cause your jitter.
 
Dan, I hadn't thought about the push/pull nature, but what you say sounds right. The hydraulic piston is in the center and it pushes on the "handle" and thus pulls on the two rods, as you say. The ram must also rest on the beam, but it hasn't lost any noticeable paint.. hum, I'll take a closer look.

I like the big wheels on your 7 ton. I considered that one and assume it, like my manual hydraulic 10 ton unit) has two speeds/powers. It uses the faster pump until the load gets too great then it shifts to a slower speed, i.e., a smaller more forceful, piston/pump... and so we can still get by with the 15 amp service.

I'll also give the axle a closer look to see if I can retrofit larger wheels. I have to pass over a section of gravel driveway and the factory wheels work, but not great. Your carrier/work table looks to be even better... one has to really bend over to put a round on the beam - I'm 6' 5" adding to the stoop distance.
 
Has anyone mentioned the fact that if the wedge end of the splitter is low, the pump will starve for fluid and stall? Make sure that the wedge end is level with or slightly higher than the motor end. Did you hear any change in the sound of the pump? A starving pump will make a kind of rattling sound from cavitation (air).
 
Thanks for the tip on level, I was operating on the open ground and didn't pay any attention to which end was higher, surely one was, the ground is not level.

I like the hand-truck idea, I may cut some plywood to fit my hand cart and strap the splitter to it. Great improvement for moving.

Dan, to you split with the splitter on the hand truck? The straps would have to be moved, so what holds it down//on? If so used.
 
The ground in WV at my cabin is very rocky, so I put the splitter on the hand truck to move it from the shed to where I split. I'd like to have even larger wheels on mine...they work fine on pavement, but not on rough ground. Let me know if you find a way to put larger wheels on!

As to splitting, I remove the splitter from the hand truck to split, putting the splitter on the ground with the wedge end elevated slightly. I've found that I can put a really heavy round on the hand truck, park it next to the splitter, lay it back horizontally, and then roll the round from the hand truck onto the splitter. They're almost exactly the same height, so it makes for easy handling of rounds that weigh over 100 pounds (even 50 pounds is rough on your back, when you're bending over).

The photo was taken the first day I used the splitter. I tried using it while it was still on the hand truck, but it was too unstable. You can see the boards I put under the handle of the truck, to elevate that end slightly.
 
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