The Forestry Forum

General Forestry => Sawmills and Milling => Topic started by: POSTON WIDEHEAD on July 20, 2011, 06:48:41 PM

Title: Hydraulics ?
Post by: POSTON WIDEHEAD on July 20, 2011, 06:48:41 PM
On my LT40HD why is it that when I lift a 20" d x 12 foot white oak or heavier, the cap comes off of the hydraulic pump and fluid shoots up like a gusher????

This always happens on heavy logs.

The cap on the pump does not screw on, it just snaps on.

I have to stop, clean up the mess, put in more fluid and by then I'm really HOT!

I'm fit to be tied!!!!

Thanks for your help. David



Title: Re: Hydraulics ?
Post by: Bibbyman on July 20, 2011, 06:55:52 PM
I don't know.  I never had that happen.  I'd guess that there is some back presure coming back through the pump.   Is your mill a standard HD with one pump or a Super with two pumps?
Title: Re: Hydraulics ?
Post by: POSTON WIDEHEAD on July 20, 2011, 06:57:05 PM
It only has 1 pump.
Title: Re: Hydraulics ?
Post by: jackpine on July 20, 2011, 07:30:12 PM
I have not had that happen either and have loaded much larger and heavier logs on my lt40hgd. Maybe someone from Woodmizer has seen this before and can answer.
Title: Re: Hydraulics ?
Post by: Magicman on July 20, 2011, 07:35:53 PM
I would call WM.  It sounds like the weight of the log is forcing hydraulic pressure back into the pump.  Something is leaking back somewhere.  Please keep us informed about what you find.
Title: Re: Hydraulics ?
Post by: bandmiller2 on July 20, 2011, 07:54:35 PM
Probibly wear in the pump,with the heavy load the pump is cavitating and forcing oil out the breather.  Frank C.
Title: Re: Hydraulics ?
Post by: millwright on July 20, 2011, 07:59:22 PM
Is there a lot of hours on your mill? It may be possible one or both cyls might have an internal piston seal leaking letting fluid get on both sides of the piston at the same time and forcing the fluid to go thru the valve backwards. I had this same problem on a john deere tractor.
Title: Re: Hydraulics ?
Post by: POSTON WIDEHEAD on July 20, 2011, 08:17:25 PM
My mill only has 144 hours on it.
Title: Re: Hydraulics ?
Post by: Dan_Shade on July 20, 2011, 09:10:49 PM
I think a call to customer service will help you.
Title: Re: Hydraulics ?
Post by: Buck on July 20, 2011, 09:14:44 PM
David, I have an 88 with 5400+ hrs that doesn't do that. I'll trade ya! ;D  I bet you'll feel much better after the call. Breathe....
Title: Re: Hydraulics ?
Post by: Log-ic on July 21, 2011, 03:56:00 AM
Hydraulics normally work pretty straightforward.. The fluid is brought under pressure and beyond the working device the pressure is released and the oil goes back to the tank.  If the log is too heavy, and can't be lifted the system would just refuse, leaving the log in place. Operator  >:( It looks like in your system the pressure is carried forward to the return line & tank instead of internal bypass.  This can be caused by many things, usually internal leakage somewhere. Has the pump ran dry? too little fluid in the system? cavitation? contamination? cloaked line? wrong fluid?  Some time ago I subscribed to the 'Inside Hydraulics Newsletter' from Brendan Casey in order to get a little more insight in hydraulics.  I have to admit that the content is often a few flightlevels too high for me to understand everything, but I did learned a lot, and I am less depending on what the chaps in the repairshop are telling me.  
http://www.hydraulicsupermarket.com
Title: Re: Hydraulics ?
Post by: bandmiller2 on July 21, 2011, 07:38:17 AM
Piston40, your not overfilling your resivour are you,those units have a rather small tank. Frank C.
Title: Re: Hydraulics ?
Post by: POSTON WIDEHEAD on July 21, 2011, 12:18:37 PM
I'm not over filling it. In fact the problem happened the first time when I only had 43 hours on it. It was delivered with the proper level of fluid in it. The first time it happened was the first big log I put on it. A 22 inch d X 12 foot pine. Fluid just started running out the bottom of the HD box. I refilled it to 3/4 of an inch from the top. It never did it again because I was sawing smaller logs. But when you lift a big log....GUSH......here it comes!
Title: Re: Hydraulics ?
Post by: terrifictimbersllc on July 21, 2011, 06:21:08 PM
Overall, what seems to be happening is that more fluid is coming back in to the pump than is going out of it.  I'm sure I don't fully understand  fluid pathways, but I'm thinking there  is a check valve not operating right, one that's supposed to be shut to the low pressure return pathway to the pump.  Do you get the same "gush" when you operate some other hydraulic function at maximum hydraulic system pressure? Like  continuing to operate the clamp AFTER it has reached its limit, either in or out?  You normally wouldn't do that very long, so maybe you didn't notice fluid coming out.    If you tried each function in/out like this, while looking at the pump vent hole, maybe you could find some differences which would help narrow down or suggest what's happening. Hoping WM will chime in soon.
Title: Re: Hydraulics ?
Post by: POSTON WIDEHEAD on July 21, 2011, 07:21:18 PM
I have tried all the other hydraulics and put them under pressure by holding down on them. Normal actions happen.
The only time fluid gushes up is when I lift a BIG 'OL log like 20d x 8 foot or longer. This should not be happening.
I called the WM reps in N.C.
Mr. Joe was really nice and is checking into it for me with the WM folks in Indiana.
Title: Re: Hydraulics ?
Post by: Bibbyman on July 21, 2011, 09:28:48 PM
I never thought about calling the area guy.  I just call Indy.  Force of habit I guess.  We've worked with them long before there were service centers and sales representatives.
Title: Re: Hydraulics ?
Post by: shelbycharger400 on July 22, 2011, 07:06:50 PM
im not familar with what you have goin on,  but is that a single stage pump or dual stage pump. ?
also what hydraulic fluid are you using in the pump?

only thing i can think of right now is either a cheapy blended oil  boiling .   sounds crude, but at 3-5000 psi, wont take much or pump is spiking due to something wrong in the pump, and a safety is blowing off? vrs blowing hoses.

its kinda out thier but working pressures and a temp guage will help.      find a way to put a guage on some line , and see what norm is,  then see what happens when you LOAD it up with a heavy log.    this will help the tech guys too.   maybe the pump spikes?  ect... then you know
Title: Re: Hydraulics ?
Post by: POSTON WIDEHEAD on July 22, 2011, 11:14:06 PM
I called WM today. The Rep and I went through the whole HD info. With in an hour, WM has me a brand new pump on the way!
I will send the bad pump back and they will do an autopsy on it to see what is wrong.

I'm telling ya, Woodmizer People will have a special place in Heaven!
These guys made me feel so much better.

I'll let ya know what was wrong with the pump if they let me know.

Thanks to all of ya'll for your support!

David
Title: Re: Hydraulics ?
Post by: Magicman on July 23, 2011, 08:36:15 AM
To me, that is the joy of dealing with a high end manufacturer, with top notch employees that are also owners of the company.  I have always found them to be very concerned about your problem and very interested in getting you back up and running.   :)
Title: Re: Hydraulics ?
Post by: Buck on July 23, 2011, 08:48:44 AM
Keep us posted on any more feedback you may get. I'm interested in the rest of the story. "Yessir", Woodmizer and the folks there are TOP NOTCH. smiley_thumbsup
Title: Re: Hydraulics ?
Post by: POSTON WIDEHEAD on July 26, 2011, 03:57:14 PM
I got my NEW HD pump today from Woodmizer. I installed it....filled it with fluid.....put on the heaviest white oak log on the yard and......BAM.....worked just like it was suppose to. NO leaks, no air in the lines or bag pressure gushing from the vent.

Michael Eichenberger was the rep. at WM who helped me. The people at WM are very helpful and will talk to you in a way that would calm a mad hornet down! Thanks Michael!

I am now back on line and the saw dust is flying.

If they tell me what was wrong with the old pump, I will let ya'll know.

Have a nice day ya'll. David
Title: Re: Hydraulics ?
Post by: Mooney on July 26, 2011, 05:01:45 PM
Awesome!  8)

I let Mike know you were singing his praises online ;-) Guess we'll keep him on the payroll a bit longer?

Title: Re: Hydraulics ?
Post by: POSTON WIDEHEAD on July 26, 2011, 06:04:25 PM
Thanks Mooney! I hope I have 40 more years.....so please renew Mikes contract.  LOL!