Hydraulic Filter Question

[Mace Canute]

I'm building a log splitter and am to the point of putting the hydraulic system together. My question is about the return line filter. All I see available from Surplus Center for return line filters are typical canister filters of varying sizes but they all pretty much say max 200 psi operation. How is it possible to put a 200 psi filter on a system that has all other components rated for 3000 psi ???? My novice approach is to put every component rated for the same max psi.

Please help.

The splitter will be : 25 gallon tank, 16 gpm pump, auto-cycle valve, 3/4 in lines, splitting cylinder, log lift valve, 3/8 in lines, log lift cylinder, return filter.

Thanks,
-unixkid

Put the filter in the return line.

Anything in the suction line has the potential to cause cavitation in the pump, a situation that will cause many times the damage than the odd bit of debris might cause and since the restriction is there 100 % of the time, so will the cavitation it causes.

If you want to have a screen, put one in the in the filler neck. That way you can see if anything was in the oil you added to the reservoir and you can remove it immediately. Putting a magnet in the bottom of the reservoir to catch any metallic particles that may be present never hurts and can always help.

So many people get hung up on filtering the oil before it goes to the pump but the wear particles that are in the oil come from the system, not from the reservoir...doesn't it make more sense to try to filter them out before they get into the reservoir? Besides...you aren't dumping dirty oil into the reservoir that you have inspected to make sure it was clean from the manufacturer, eh.

Back to the filter...the only thing you have to be careful of is that the filter base has a bypass built into it. The bases I have seen have had a bypass pressure of 25 PSI.

 

[ilander]

Thanks for your in depth reply, very informative. The manual for the DX25E recommends only one hydraulic oil. I just looked up that filter that spits past the gasket in extreme cold weather, it's a 10 micron. The NAPA folks fixed me up with a 20 micron for extreme cold. Also, the filter on the suction side of the pump is a 20 micron. What I have done with this tractor since new is not to work the tractor until the engine temp is normal.

I did some extensive work the the DX25e last summer which included replacing the trans-axle case (it was cracked), it meant complete total disassembly of the back of the tractor. I realize all those gears and bearings swim in this oil, but there was little sign of wear. Also the pump pressure was checked and the cylinders appear to travel as fast as when new. That's the good news.

The bad news, and I welcome comments here, is the HST unit appears to be shot. When cold the tractor travels and works OK, winter operation is acceptable. In the summer the line going to the control valve in the cab gets so hot you cannot touch it, and under a heavy load the tractor wants to stall and the HST chatters.

I see this as my fault, because the plastic fan under the tractor cooling the HST lost all it's blades and I unknowingly ran it pushing and dozing dirt up hill on a few hot summer days, and I think that's what fried the HST as that's when the problem started. Also this tractor is weighted down to maximum weight with attachments (heavy duty dozer on front and one of a variety of attachments on back), so even when just driving it around it is working. I now see cold weather lack of lubrication as possibly helping ruin the HST.

I plan on repairing the HST next summer, but before even starting that project I want to install a oil cooler ahead of the engine radiator. That filter that gives problems I discussed is between the engine driven main pump and the HST unit, I plan on tapping into that circuit just ahead of that filter to plumb that cooling radiator.

Do you see any issues with where I plan on tapping in for the cooler?

Another question, I can disengage the gear transmission and run the HST during cold weather warm up if I want to. I've thought of doing this to circulate and warm the oil because even with the engine warm, when first using the tractor in cold weather it is sluggish until the oil gets warm. Do you see any issues with this running of the HST during warm up? These parts are so expensive I only want to do repair it once, so I want to do anything preventive.