Hydraulic Maintainence

Bone Saw

I have had this kanga skid steer for about a year and a half, and I haven't done a lick of maintainence to it other than change engine oil. I have some downtime now that I finnished the big fence job and want to go over this machine with a fine tooth comb. I just finnished replacing all pins and bushings and cleaned up the engine (filthy) cleaned up the carb, new ignition coils. Now I want to address the hydraulics. Everything works fine and no leaks, A few hoses I want to replace and orings and seals on the cylinders, but I am unfamiliar with proper procedure for opening up/draining/refilling everything. How do I get the old fluid out of the lines, valves, cylinders? should I even bother ? do I just disconnect lines and preassure and return filters and let it leak everywhere? does the system need to be primed upon refilling??? I'll take any and all hydraulic maintainence input out there. Tia

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PipeGuy

The first thing that comes to mind is: follow whatever recommendations the manufacturer may have. That being said, if you're not looking at fooling with more than 5 or 10 gallons of hydraulic oil, it's probably worth changing it. There oughta' a drain plug on the tank or a 'main hose' that's fairly easy to take off.
We change hydraulic filters every 250 engine hours. We generally won't change hydraulic oil at shorter than 1000 engine hour periods because of the considerable volume involved, the "closed" nature of the system" and the lack of oil exposure to cumbustion by-products. We do however watch for signs of change in the oil color that might be indicative of contamination or degradation.

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tgeb

Hey Bonesaw.

You don't mention how old this Kanga is only that you have owned for about 18 months.

I would most deffinetly drain the planetary drives and refill, (they are what drives the tracks) if you haven't already done so.

As far as the hydraulics, I agree with Pipeguy a simple drain and refill of the reservoir should be sufficient.
Be sure to purge the air out of the system before putting any of the circuits under full pressure. The high pressure can cause any air pockets in the cylinders to burst/explode which can cause pitting inside the cylinders.

As far as replacing "O" rings etc. if they aren't leaking I typically leave 'em be, as opposed to risking introducing contamination to the system. The key thing with hydraulic systems is cleanliness.

If you take something apart and reassemble it make sure it is absolutely spotless...then clean it again to be sure.

Again be sure to purge the air by gently working the cylinders a few times to get the air out before applying full pressure to the system.

Let us know how you do, or if you run into any snags.

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Tom

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Bone Saw

this is exactly what i was looking for thanx guys, how do i purge the lines, can I disconnect spark plug cables and crank the engine??? again tia
btw I think it is 4 years old, I;m guessing purging the drive motors will be easier since they are the lowest???

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tgeb

No, that's not exactly what I meant.

To purge the air out of the hydraulic system you simply need to start the engine and while running at low to moderate engine speed raise and lower the cylinders, dump and curl the bucket. Do this for 10 or so cycles and that should get the air out of the cylinders.

Do not over pressure the system as in letting the cylinder reach the end of it's travel and continue to push oil to it, when at the end of it's stroke stop and reverse flow.

I think draining all the hydraulic oil (cylinders and drives) would be overkill.

As far as the drive motors they may or may not use the same hydraulic reservoir, most likely the share oil with the rest of the hydro system.

What I was speaking of was the planetary drives that most of these type machines have now. this would be "out board" and serviced by draining and refilling the oil.
One on each side of the tractor where the tracks meet the drive gears, an area that holds the sprocket should have a couple of recessed drain plugs that are positioned at 90 degrees from each other.
With one plug at 6 o'clock the other would be at 3 or 9 o'clock. Drain the oil from the 6 o'clock plug, replace the plug and fill through the 3 or 9 o'clock plug till oil runs out. That's should be the correct level.

I have only seen a few of these Kanga's but I am almost certain they have these planetary drives, and these do need to be serviced regularly. Most likely gear oil is required 85-90w or 75-140w something like that, Not hydraulic oil, check the manual to be sure.

Let me know if I haven't confused you yet! I'll put some mumbo-jumbo in the next post.

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Tom

www.gebcon.com

Bone Saw

I'm reading you lima charlie now Tom So the planetary oil is seperate lubericating oil that is not part of the hydraulic circut? thanx again

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690E

drop 80 bucks for the service-op manual and its money well spent. You can make big mistakes without it. Never open up hoses and joints to get oil out, and fix seals only when they die. Change the hydraulic sys filters more often than required, and determine the timing by cutting into them and checking for contamination. If you want to save oil, build a oil filtration cart and fine filter the res when the machine rests.

It may interest some of you to know that John Deere has a service bulletin out that says to use DELO or similar in the 690e and other excavators hyd. systems because it has more anti-oxidants in it. Since than, I buy DELO [or local equiv.] by the 55 gallon drum and use it in all machines hydraulic systems and engines and even in backhoe-loader transmissions. Much easier inventory plan and no goof ups with goober putting hydraulic oil in to engines. Use it in all trucks and autos in the yard too. I will never go back.

And yes the Planetary drives need gear oil as they are seperate from the Hydraulic system. I do have a Ford backhoe that takes DELO OR gear oil in the final drives, transaxle . Get the book!