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Author Topic: Hydraulic fluid a bit thick I guess  (Read 965 times)

Offline furu

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Hydraulic fluid a bit thick I guess
« on: February 21, 2018, 02:04:16 PM »
Went out to saw a bit yesterday.  Did not think it was really that cold.  Barely could get the saw head to go up, very slow.  Would go down pretty well.  Traveling on the track was an exercise in patience.  All of this just while trying to set it up for the first cut.  Looked at the hydraulic fluid temp and it was below 0 C /32 F by several degrees and decided that was the problem.  Put a stick in to the levers for the log turner and left for 20 minutes.  Came back and ran the mill up and down the tracks about 4 times and it started to become normal.  Don't think I have ever seen it that sluggish before.  I know some of you folks mill at temperatures well below what I experience.  What do you do to warm up the hydraulic fluid to where it flows normal when cold?
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Offline mountainlake

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Re: Hydraulic fluid a bit thick I guess
« Reply #1 on: February 21, 2018, 06:13:11 PM »

 It really shouldn't be that sluggish at 32f,  check the drive belt on the pump for slipping.  Steve

Offline starmac

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Re: Hydraulic fluid a bit thick I guess
« Reply #2 on: February 21, 2018, 06:26:01 PM »
This is not on the mill, but the principle is the same.
On our equipment in the woods, once we have the engine warmed up, we will sit there putting all the hydraulics through their paces for several minutes, including lifting one side at a time and running the tracks for a while,, spinning the grappel, extending all the cylinders several times, the whole works.

I have never used my mill in cold weather, but the original owner did and it has heater pads installed on every cylinder.

We also use aircraft hydraulic oil up here.

Offline bandmiller2

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Re: Hydraulic fluid a bit thick I guess
« Reply #3 on: February 21, 2018, 06:37:30 PM »
Furu, you would probably be best served with synthetic hydraulic oil, its expensive but helps in the cold and heat. Frank C.

Offline drobertson

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Re: Hydraulic fluid a bit thick I guess
« Reply #4 on: February 21, 2018, 09:35:46 PM »
My 40 super ran slow when first starting in cold weather,, I did the same as starmac, I would run it through the cycles while the engine, and myself warmed up, I cant' remember the coldest I've sawed, but know it was well below freezing, in the teens for sure.  As I got older and following two back surgeries,  I struggled to saw at times around freezing, but mainly due to windy conditions, not a fan of the wind and cold. Plus I have Raynoids, and my fingers go bonkers, plum shut down if I go to long,  i'd say frank may have the best idea yet,,

Offline furu

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Re: Hydraulic fluid a bit thick I guess
« Reply #5 on: February 21, 2018, 11:02:53 PM »
This is not on the mill, but the principle is the same.
On our equipment in the woods, once we have the engine warmed up, we will sit there putting all the hydraulics through their paces for several minutes, including lifting one side at a time and running the tracks for a while,, spinning the grappel, extending all the cylinders several times, the whole works.
We also use aircraft hydraulic oil up here.

That is basically what I have done.  Run the log turner motor continually until the other motors warm up enough to run back and forth then run the mill head up and down and then down the track and back etc. 

Today I checked the hydraulic temp when things seemed normal, the hydraulics did not run well until fluid temperature got up to 5C/41F.
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Offline mountainlake

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Re: Hydraulic fluid a bit thick I guess
« Reply #6 on: February 22, 2018, 04:17:10 AM »
 

 Check that drive belt.  Steve

Offline Ox

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Re: Hydraulic fluid a bit thick I guess
« Reply #7 on: February 22, 2018, 10:47:47 AM »
How about running ATF in these hydraulic systems?  It's a good oil that doesn't thicken to the point of sluggishness unless extremely cold and has good cleaning and anti-wear properties.  It's what we run in cold weather systems here in the cold and it saves money over "special cold weather oil".

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Offline furu

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Re: Hydraulic fluid a bit thick I guess
« Reply #8 on: February 22, 2018, 10:50:42 AM »


 Check that drive belt.  Steve

Yes I did as you suggested because I agree that it should not be that sluggish at 0C/32F temperature and belt tension is fine.

It does bring up the question of the pump output.  Might I be  having a pump problem?  Would not surprise me with all the issues I have had with this mill.  Would not think that would go away however as the fluid temp comes up.  Might have to put a gauge on to check the pressure.  I don't really have a good way to check flow rate however.
Of course after yesterday's blade breakage I need to figure out how to repair the lube system as the blade took out the system.  Another break at the blade weld.
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Offline mountainlake

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Re: Hydraulic fluid a bit thick I guess
« Reply #9 on: February 22, 2018, 03:34:24 PM »
  Did you look at the belt real close to make sure its not glazed over and slipping, also check the pulley on the pump to make sure its not slipping(not likely but possible) When your pump works good hot it not shot. They delivered my brothers mill when it was -5 f and the head went up and down fast right away , my mill is a little sluggish for about 10 minutes at 0 f with regular hyd oil .  I got rid of that flexible plastic piece of junk for the lube and installed a steel pipe soon after I got my B20 . That steel pipe hasn't moved in over 10 years .  Everyone breaks blades but you should get around 7 sharpening or more.  The 2 worst blade breakers are running the flange on the guide wheel to close to the back of the blade on these high powered mills and worn v belts, after that a bearing going out will also break blades.  Get that flange running at least 1/4" behind the back of the blade when tensioned, measure it, don't guess. Also check on the movable guide the 1/4" back is the same when all the way in and all the way out.   Steve
« Last Edit: February 22, 2018, 03:46:23 PM by mountainlake »

Offline furu

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Re: Hydraulic fluid a bit thick I guess
« Reply #10 on: March 10, 2018, 06:36:42 AM »
I did not post back on this issue as it resolved itself as soon as it hit 33 degrees.  No more issue. 
No belt issue no glazing and no slipping.

It had been getting slowly worse with the colder temperatures and I am now pretty certain that it is in the spool valve (SV ) assembly. 
Whether it is internal to the SV or is external in the linkage I am not positive but I think that it is internal. 
I am pretty certain that the mill uses an open center hydraulic system and not a closed center.  I know when I got the mill and had an early-on hydraulic issue, along with all the other issues, I contacted the tech support folks and the individual I talked to was not able to answer the question as to open or closed.   I was left to resolve that hydraulic issue on my own like others.  It is very dependent upon who you get on the phone.

I need to look at what can go wrong in the SV  that would cause the problems  I had.  At one point I could get one SV to run the log loader but only if I pushed the dog clamp SV at the same time in the opposite direction.  Almost as if it was diverting the fluid.  Normally only one SV on each valve bank can be used at a time because of the prioritization of the system.  Same thing was true of other SV's on the SV bank.  Saw Head would only move up or down if another SV was actuated in the opposite direction. 


As to the blade breakage yes it happens and if run long enough every blade will break.  They should not break in the weld in every instance and not at the frequency that these have.
As to getting 7 sharpenings or more.  ::) 
Well I have 11 "brand new" blades that have never made it to the sharpener even once as they have broken before they have had a chance to get dull.  All in the weld.  I won't openly speculate, as I have no proof, as to why I got 24 included blades with the mill but I have my suspicions.

As to the roller guides, the manufacturer states to set the flange 1/8" back and many people including you, mountain lake, say use 1/4". I measured to verify where mine are at and I am at 7/32 so 1/32 less from the 1/4" that you recommend.  Close but I can adjust them to the full 1/4".
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Offline mountainlake

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Re: Hydraulic fluid a bit thick I guess
« Reply #11 on: March 10, 2018, 08:49:10 AM »

 It does sound like something is sticking in the one of the valves when cold, I'd be pretty sure its a open center system..  Blades breaking at the weld is not the saws problem , its a bad weld most likely not annealed right.  In all of these years I've had maybe 3 break in the weld.  It would be hard to pinpoint which valve is bad. I might try capping off 1 valve at a time and seeing it made a difference.  Steve

Offline starmac

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Re: Hydraulic fluid a bit thick I guess
« Reply #12 on: March 10, 2018, 12:03:38 PM »
If the hydraulics are working like they are suppose to since it has warmed up. It is possible that it was just a sticky valve and it will clean itself up over the summer, and never show it's head again.

Offline Crusarius

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Re: Hydraulic fluid a bit thick I guess
« Reply #13 on: May 30, 2018, 10:32:43 AM »
If thats the case I would change the fluid and do my best to make sure water can't get in it.