Hydraulic oil question.

Mick!

TreeHouser
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Hi Gearheads,
I have had a small issue with a chipper I have, it's new to me so I'm just sweeping up some issues of neglect.
Because I've been up the tree I've been unable to use it much but I've (when I say "I" it means the Dutch engineery sort that works for me) noticed the roller motor gets hotter than it should, plus, although I cannot 100% confirm this, he says crushing power diminishes a bit.
He is of the opinion that the hydraulic oil is finished and too thin, I hope he's right as it's an easy fix. So I've drained the oil and taken off the filter ready for the motor factors to open Monday.
I have an unopened 20 litre can of tellus s2v 46 the manual calls for ISO 32. Is this compatible? I've no objection to buying the right stuff but wanted to check it's not the same.
As usual, thanks in advance.
Mick
 
Mick, 46 is a higher grade than 32 anyway. What you dont want is to run 32 in equipment specced to run 46.

Hydraulic motors do wear, and as they do, they loose power when they get hot. New motors on a small chipper are cheap enough though. What model is it?
 
46 Should work fine in your application. Your not running any high speed motors or spindles.

If the heat issue persists, check for a stuck pressure relief valve. Also installing a couple pressure gauges lets you see what changes between cold and hot operation.
 
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  • #7
Thanks, first stop tomorrow is a hydraulic specialists where I'll get a tester, a filter and a price on a couple of new motors.
If they don't break the bank I might just throw them on.
 
Also, any restriction -- such as a flow limiting orifice, or valve -- will generate a tremendous amount of heat. I'd look for something that is restricting the oil flow, such as a valve that may have been installed as a way of slowing down the in-feed rollers.

Joel
 
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  • #14
Ahhhhhh, interesting you say that, there is a turn valve for slowing down the rollers, and it was whilst mucking around with that the problems started. Yesterday I changed the oil and filter and took it out the back, I spent 15 minutes running big wood through it, the rollers were great (apart from the bottom one occasionally stopping and only restarting once reversed, but I put that down to a stuck chip behind it)
The hydro motor warmed up a bit, I don't really know what level would be normal.
I think we take it out for a few days, leave the turn valve alone on medium setting, and see what we see.
Thanks for all the help.
 
Mick,

You can use that speed limiting valve to help warm up the hydraulic oil during cold weather operation. Close down the valve at engine idle. Let the system run a few minutes with that roller speed limiting valve set in the nearly closed position, then open it up for normal operation. Cold hydraulic fluid is very difficult to move. Warming the oil up a bit prior to heavy use will help a whole lot.

Joel
 
The hydro motor warmed up a bit, I don't really know what level would be normal.

Anything over 250F will start to cause damage to the oil.
My rule of thumb with hyd's is I should be able to touch it bare handed for a split second. May not be able to hold on to it, but still touch it with out burning.

Which in the winter is a nice way to warm your hands.
 
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  • #17
Well it seems to me that the motor is nice to touch, warm rather than hot.
It never gets that cold here TBH.
Like I say we'll rag her for a couple of days, get to know the machine a bit better and I'll report back.
 
I've seen the paint melt on the hydraulic tanks of really big chippers and forestry machines when the oil gets hot. If your motors are just warm, chances are there's no problem.
Also, always leave the speed valve fully open.
 
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  • #20
I suspect you're right Ed, no real issue, the thing is with having the rollers flat out it seems to push the wood on to the cutters too quickly, yes it has a stress control but it's all a bit well....dramatic, maybe it's my imagination, we've only used it for a couple of hours max. Today space was tight so we took the 6 incher.
 
Typical timberwolf, only time you might want to turn it down is for very wet conifer or something that might not trigger the stress control but the volume and stickiness of the material might clog the chute.
 
My hydraulics troubleshooting book states in bold letters.....Hydraulic oil should never exceed 175 degrees F.

Temps exceeding 175 will quickly take out seals in pumps, motors, valves and cylinders. The heat will eventually cause catastrophic hose failures. Heat will also cause the hydraulic oil to degrade, destroying its lubrication properties.

If temperatures routinely exceed 175 degrees F, it will be necessary to install an oil cooler in the return line // increase the size of the oil reservoir // or both.

Joel
 
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