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SmilinSam

Loader hydraulics question

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SmilinSam
On these small garden tractor loaders , would it be advisable to put a oil filter setup in the system? None of them have them , not kwik-way, , Johnson, nor the simplicity loaders. It wouldnt be hard to add one in, just dont know whether or not doing so would create any problems? Also, if I do add one in where do you put them? Most I see go on the return side of the control valve where the oil is on its way back to the resevoir. Thanks Sam

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Kent
Yes, Sam, I think it is advisable -- though I'm certainly no hydraulics expert. I've had to learn a lot about them with my all-hydraulic Power Trac. I'd recommend a 10-micron filter in the low-pressure line. One option is the return line but another is in front of the pump, to protect it from contaminants. As long as you deal with the low-pressure side of the system, both the mounts and the filters are inexpensive. Napa Gold 10-micron filters are typically are in the $10 range. Putting it in the return line is safe for the filter and the system -- but all it does is clean the oil. It doesn't really protect the pump or cylinders from contaminants -- it's filtering contaminants out after they've been through both the pump and the cylinders. Putting it in front of the pump, in the supply line protects both the pump and the cylinders. Just don't let a filter in front of the pump get clogged, or you'll ruin the pump when it cavitates from lack of oil flow... If you put a filter in front of a pump, on the suction side, you need to change it regularly and religiously. My Power Trac calls for replacing the filter every 50 hours.

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D-17_Dave
The only filters in front of a pump will be simple full flow strainer style filters. They will protect the pump from large debris that could cause a catastrophic failure y locking up the pump. Any other would likely starve the pump flow as Kent described. NEVER place a cartridge filter in the high pressure side of any system as they are only good for around 100psi. There is usually little to no back pressure from the valve to the tank on the return line so this is the logical place. The thoughts here are that any debris will come from the pump, motors, cyl's, or lines so if you catch it before it returns into the reservoir then your covered. This work as long as kids aren't filling the tank with dirt, pencils, or whatever else is lying around. The exception is water contamination. Condensation will collect in these tanks and turn the fluid to a milky looking flow. This will also lead to rusting inside the tank and any other long term exposed component.

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Kent
My Power Trac has a filter on the intake (ie suction) side of the charge pump for the main variable-displacement drive pump. But, like I said, it requires changing the filter every 50 hours or you'll void the warranty, etc.

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SmilinSam
quote:
Originally posted by D-17_Dave
...... This work as long as kids aren't filling the tank with dirt, pencils, or whatever else is lying around....
OOOOOO I think I will definately put one in, but on the return line. Dont want to worry about CRS wrecking the pump. Any filter is better than none I guess when it comes down to it. Will have the hydraulic lines all torn apart anyhow to move the control apparatus around on the tractor, so it will be an easy addition. Thanks Kent and Dave for the help.

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HubbardRA
Most dirt is picked up from the rods of the cylinders. The first time this dirt is introduced to the fluid tank is from the return fluid from the cylinder. A return filter is totally adequate for this dirt. Just be careful when adding fluid to the tank so that you do not introduce any dirt that will go through the pump and valve before getting to the filter.

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KSever
Good question and I learned allot Sam, Thanks for asking and Thanks everyone who responded. I am just about to install my loader and pump on my Ford Jubilee, I didn't even think about a filter but I am now.

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SmilinSam
OK, I have another filter question....8) I see I have some water in my hydraulic oil ( ATF) as its pink in color rather than red. I have the filter and have to go back to the store for some different fittings tomorrow. Should have it on tomorrow evening. Question is, will the filter work to gradually trap the water at all in the bottom of the filter? And one more.. The tank has a solid plug and no breather. All the cylinders are double acting cylinders, and as I have read elswhere, the tank should not need vented in this case. Is this correct?

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BLT
quote:
Originally posted by SmilinSam
OK, I have another filter question....8) I see I have some water in my hydraulic oil ( ATF) as its pink in color rather than red. I have the filter and have to go back to the store for some different fittings tomorrow. Should have it on tomorrow evening. Question is, will the filter work to gradually trap the water at all in the bottom of the filter? And one more.. The tank has a solid plug and no breather. All the cylinders are double acting cylinders, and as I have read elsewhere, the tank should not need vented in this case. Is this correct?
As the oil heats up you need some room for expansion. My gut feeling that a breather would be needed, especially with ATF as it expands a lot when heated. I can't find my hydraulics book now to confirm it. You can get breather that offers filtration. As far as spinning water out of ATF, I have not seen anything to cure that. You can do it with #2 Diesel fuel and that's about it. If there was something available , you'd see it in the heavy duty automotive market and the military and I have seen nothing yet.

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HubbardRA
The heating up of the oil will produce some pressure in the reservoir tank, but not enough to cause any problems. This is why usually even the return hoses will take around 400 psi. Pressure in the tank does not have to be zero. If you put a breather on the tank, then you will be letting moisture in from the humidity in the air. With all double acting cylinders the volume change is relatively small and you should not need a breather.

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D-17_Dave
If you already have moister contamination in your oil you'll need to flush it out. The filter will only separate the water that is settled from setting stagnant. The problem is once the water/oil passes through the pump it mixes them together hence the pink milkshake you see. If you have this mix you have a substantial contamination problem already and it'll need the flushing. If the filter catches enough water it will block the filter and cause back pressure which will lead to the filter blowing it's casing. Unlikely if it's mixed as much as you say, but it's possible. Also if you have this much in the system I'd bet you have some sort of vent somewhere that has allowed the system to ingest some rain water or as Rod said many years of condensation. The cylinder displacement does vary a little due to the rod taking up some of the displacement when retracted. There are a lot of industrial applications of pressurized hydraulic systems but I've never seen anything but a vented system on such small, light duty systems like this. Kent, is the filter on your hydro on the suction side of the charge pump or on the pressure line from an external charge pump supplying charge oil to the hydro?

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SmilinSam
Heres what I came up with for filter arrangement..
[img]http://i686.photobucket.com/albums/vv227/Smilinsam/Deere/picture064.jpg?t=1244601517[/img]
First fit resulted in two leaks. Second time I have one other drip to deal with. Need more tape on the joint I think. Plumbing is no fun to meC I drained the resvoir and used a suction tube to get the oil water mix from below the drain point. Still, that leaves the contaminated oil in the cylinders and lines to deal with. It seems to run and work fine, despite my vise grip pliers method of operating the broken spool end for the bucket dump. Havnt figured out what I am going to do about that yet.

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Kent
Dave, It's on the suction side of the charge pump. The charge pump is built in to the variable displacement pump. This particular Power Trac (they differ quite a bit from model to model) uses a closed-loop drive system, with no case drains, and the charge pump only replenishes the main pump, and bypasses the rest. I think the charge pump is 4gpm max and the main variable-displacement drive pump is 16gpm max. Like I said, religously changing this filter is the primary maintenance task on the machine, other than greasing it... it's the only filter on the whole system, which holds 10 gallons. Sam, An aftermarker loader valve bank, like a Prince brand, should only cost about $150 or so, if you shop around, and getting a loader back in good operating condition is certainly worth that kind of investment.

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D-17_Dave
Looks good Sam. Kent, the smaller pumps like your using are the same as the built in charge pump models like on my 620. As you get up into the larger pumps they use the outboard mounted gear pumps that work the aux. circuits and split the flow off for charge pressure. I didn't know if your MT had that large of a hydro since it's heavy duty and all wheel drive. Just a case of curiosity.

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Kent
quote:
Originally posted by D-17_Dave
Looks good Sam. Kent, the smaller pumps like your using are the same as the built in charge pump models like on my 620. As you get up into the larger pumps they use the outboard mounted gear pumps that work the aux. circuits and split the flow off for charge pressure. I didn't know if your MT had that large of a hydro since it's heavy duty and all wheel drive. Just a case of curiosity.
It has a total of four pumps, if you count the charge pump as a separate pump. The variable displacement drive pump with it's built-in charge pump hangs off the fan side of the Kohler CH-25, while a pair of piggy-back 8gpm fixed-displacement pumps hang off the flywheel side. One 8gpm pump is for the hydraulic PTO, and is solenoid controlled to bypass back to the tank. The other is split between the loader (two lift, one dump cylinder), the two steering cylinders, and the "Aux PTO" circuit that's used for the hydraulic quick attach cylinder, or on implements such as the grapple on the grapple bucket, the bucket curl on the mini-hoe, etc. I think the larger Deutz diesels hang all the pumps off one end of the engine. I know the newer Robin-powered gas models do...

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SmilinSam
quote:
Originally posted by Kent
if you shop around, and getting a loader back in good operating condition is certainly worth that kind of investment.
No argument with that, my problen thus far is finding one with 1/2" in and out ports and 3/8" cylinder ports. Everything I have seen so far is 3/4" and 1/2". These valves are about twicwe the size of the one being used now. Way too massive. The other problem is that the hoses on this one are not an off the shelf item. If I dont get an identical valve that can accomodate the hoses and fittings on this one, then the cost of new hoses with fittings to adapt to this could be really cashy.

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Kent
Sam, Couldn't you use reducers in the larger ports of the valve bank to adapt them down to your hoses? If the bank would physically fit where it needs to go, adapting the hoses wouldn't seem to be that costly or complicated. Surely they make adapters that'll handle that kind of pressure.

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SmilinSam
Ok, heres yet another question. I loooked on EBay and found some valves. What does size SAE 10 and SAE 8 translate to in terms I can understand with my 3/4, 1/2, 3/8 " pipe thread terminology?XX(

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HubbardRA
Keep in mind that there are three basic types of fittings used on hydraulic hoses. NPT - pipe thread connections SAE - straight threads with O-ring seals JIC - 37 degree flare fittings like is used in tubing. You will need to purchase an adapter to go between one type and another. You can check with Surplus Center for the adapters.

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