Oil & Fuel Tips / Techniques to changing Hyd Oil

[Bob999]

I was told that if you mess with the wheel motor circuit you should put on a 3 micron filter.

Bob--I don't doubt that you were told that. However I don't understand what the thinking and logic behind it could be. Because the hydraulic filter specified by PT is a 10 micron filter and the charge pump is continually injecting some new oil into the wheel circuit it seems to me that 10 microns is the relevant number--that the system would rather quickly reach an equalibrium of 10 microns even if the initial charge in the wheel circuit were cleaned to 3 microns.

 

[KentT]

Bob--I don't doubt that you were told that. However I don't understand what the thinking and logic behind it could be. Because the hydraulic filter specified by PT is a 10 micron filter and the charge pump is continually injecting some new oil into the wheel circuit it seems to me that 10 microns is the relevant number--that the system would rather quickly reach an equalibrium of 10 microns even if the initial charge in the wheel circuit were cleaned to 3 microns.

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Bob999,

What would you think of plumbing in a 10 micron, high-pressure filter on the PTO return line back inside the tub, rather than up front? Then, you'd be filtering 8gpm (on the PT422/425) at all times...

 

[Bob999]

Bob999,

What would you think of plumbing in a 10 micron, high-pressure filter on the PTO return line back inside the tub, rather than up front? Then, you'd be filtering 8gpm (on the PT422/425) at all times...

I think it is a great idea if you can figure out how to do it. I installed a filter on the return line on my mower--it is presently the only attachment I have that uses the PTO. I put it on the mower because there was space for an easy installation. I could not figure out where to install a filter on the PTO return line on the tractor--the PTO line is 3/4" hose and with the filter and fittings it just took too much space.

 

[J_J]

I think it is a great idea if you can figure out how to do it. I installed a filter on the return line on my mower--it is presently the only attachment I have that uses the PTO. I put it on the mower because there was space for an easy installation. I could not figure out where to install a filter on the PTO return line on the tractor--the PTO line is 3/4" hose and with the filter and fittings it just took too much space.

Bob,

I believe that one of the PT guys has already installed a high pressure filter in the PTO circuit. If not, there are two places that I can think of that a high pressure filter could be installed. A filter could be installed in the output line of the PTO solenoid manifold. When the PTO switch is off, the fluid is routed through the manifold and returned to tank. A filter could be installed in the PTO pressure line on the lift arm. Just cut the hose and install new fittings to accommodate the filter, and when you are using the PTO, you are filtering the fluid going to the hydraulic motor on the attachment. If no attachment is installed, just connect the PTO hoses together and cut the switch on, and fluid will go from the pressure side, through the quick disconnects, through the filter and back to tank. Just be sure that when you turn the PTO switch on, that you have a hydraulic fluid path to tank. If you do turn the PTO valve on, and the fluid has no place to go, the engine will stall, or the relief valve will activate, and you will know that something is going on that is not right.

 

[BobRip]

Bob--I don't doubt that you were told that. However I don't understand what the thinking and logic behind it could be. Because the hydraulic filter specified by PT is a 10 micron filter and the charge pump is continually injecting some new oil into the wheel circuit it seems to me that 10 microns is the relevant number--that the system would rather quickly reach an equalibrium of 10 microns even if the initial charge in the wheel circuit were cleaned to 3 microns.

I don't understand it either and I don't know of anybody who has done it.