Need advice hydraulic fluid change wood splitter

[Knot2fast]

Hello I'm looking for advice on how to change hydraulic fluid in homemade wood splitter that I got. After motor blew it sat for many years unused outside before it was given to me. I replaced the motor and tires and got the rust off the beam and rebuilt the Pusher block so now everything works. Since it was homemade there is no manual and I have not changed hydraulic fluid on a splitter before. Fluid looks okay but I would rather start fresh so I know what I have no telling how long it's been in there. do I have to get fluid out of RAM, or just drain the tank. How do I keep air out of the hydraulic lines and if I do get air in them is that a problem?

 

[ValleyForge]

Just drain the tank and refill with AW32 grade hydraulic fluid. if you think the fluid has water in it, then drain the ram by removing the fitting to get out as much as you can. my splitter holds 25 gallons, so the ram isn’t that much of the total and I don't bother with it.

 

[Knot2fast]

Wow! that was A quick Response,thank you!

 

[husky455rancher]

It could have atf in there too.

 

[angelo c]

My Timberwolf calls for aw46 fluid.

Just saying

 

[Knot2fast]

Yesterday I picked up a 5 gallon pail of VP racing hydraulic oil from Tractor Supply, the label listed all sorts of equipment that it's suitable for hydraulic systems and log splitters. I just looked at the label and it does not say anywhere aw32 the only viscosity or weight that I can see on it says SAE 20 or ISO 68 do I need to return this and keep looking for aw32 or is it the same thing

 

[ValleyForge]

My Timberwolf calls for aw46 fluid.

Just saying

AW32 is more for pump systems but they are interchangeable..It’s a homemade unit, thus the recommendation…

 

[ValleyForge]

Yesterday I picked up a 5 gallon pail of VP racing hydraulic oil from Tractor Supply, the label listed all sorts of equipment that it's suitable for hydraulic systems and log splitters. I just looked at the label and it does not say anywhere aw32 the only viscosity or weight that I can see on it says SAE 20 or ISO 68 do I need to return this and keep looking for aw32 or is it the same thing

Are you going to use it in the winter or summer? 68 is a bit thick for my liking is pumped systems when it’s cold out…

 

[Knot2fast]

Spring and summer, I rarely split anything in the winter. I've been hand splitting since I was a kid this is my first log splitter

 

[BrettS]

I've been hand splitting since I was a kid

Yep know that one, still do until I go to the farm and use their splitter.

 

[cookies]

iso46 is middle of the road and what I went with over 32 for better protection in higher temps. iso32/46/64 etc are all 20 weight oil but the polymer additives thicken them up once heated above 160ish degrees f. Since it sat so long I would grab a 5 gallon bucket of the tractor supply/ menards etc store brand hydraulic fluid and use that as the flush and run it a few hours hard incase it starts leaking or shows contamination after use then if its in good shape put a high quality fluid in and change the filter and your ready for long term use.

 

[northmanlogging]

drain it, replace with AW-46, cheaper and easier to get then AW-32, thicker too so it won't leak as fast.
if you're concerned about moisture in the cylinder, only fill it about half way, then run the ram a few times, drain repeat.
It won't get all the water out in the first try, but make sure everything is sealed up, or at least covered then get it nice and hot for an hour or 2 and any remaining moisture will hopefully evaporate out.

Absolute worst case, water got into the pump mechanism and corroded stuff, or into the cylinder and corroded around seals. But only way to find out other then complete tear down is to just run the damn thing and see what it has to say.

 

[ValleyForge]

Spring and summer, I rarely split anything in the winter. I've been hand splitting since I was a kid this is my first log splitter

I just noticed you’re in the northeast, so I would tend to recommend a thinner weight oil, just to be safe. I don’t think tractor supply has aw32 since it is primarily a pump oil,

aw32 = 10 weight
aw46 = 15 weight
aw68 = 20 weight

I'm fixated on the fact that your unit is homemade, not that that is a problem but I immediately think hydraulic line sizing. The most stressed part of an hydraulic system is the pump suction and more often than not, it is undersized on home made units. I am still sticking with my original aw32 recommendation. I usually get it from NAPA If that helps

 

[Knot2fast]

These oil viscosities tend to get confusing for me but what you're saying is the aw32 is thinner than the 68 so it would be easier for my pump if I have an undersized pump to push . does that coordinate to slower push speeds or faster push speed?

 

[davidprivett]

while you have it apart kinda have you thought about adding a hydro filter in the system to catch any debris in the system?

 

[Knot2fast]

It has one

 

[ValleyForge]

These oil viscosities tend to get confusing for me but what you're saying is the aw32 is thinner than the 68 so it would be easier for my pump if I have an undersized pump to push . does that coordinate to slower push speeds or faster push speed?

That’s a complicated question, log splitter pumps are typically positive displacement which means they ‘pull’ a unit of fluid in and ‘push’ that same unit out. The pull fluid in is the concern with these pumps. Thicker fluid is harder to pull in and that side of the pump is not pressurized and only has the atmosphere to assist in its movement. That’s why the suction line is usually the shortest and biggest diameter to reduce pressure losses to atmospheric pressure. These losses rob engine power which reduces rpm and adds heat. Reduced rpm and increased pressure losses from ‘working‘ on the suction side of the pump translates to reduced flow and pressure available to the ram where you want the work to happen.

many people say the added heat is why they need a more viscous fluid, but it’s the viscous fluid robbing power and adding heat. It’s a viscous hydraulic circle. That is why you see the better splitters have huge hydraulic tanks, to manage the heat better and allow taking advantage of a lower viscosity fluid which maximizes power available at the ram.

 

[Knot2fast]

Ahhh, that makes a lot of sense. I understand it much more thank you.

 

[ValleyForge]

Ahhh, that makes a lot of sense. I understand it much more thank you.

That looks like a nice machine for home made…it should serve you well.

 

[Knot2fast]

That looks like a nice machine for home made…it should serve you well.

The frame is oil reservoir and cap has a hole in top, I put a bolt in the top hole to close it so hydraulic fluid doesn't leak when I move the splitter. do I need to keep that open when it's running as a vent ? There wasn't anything in there when I got it.