I'm no expert and I have Fisher plows. One place moisture gets in is condensation, there is an air gap in the reservoir, every time it gets colder water condenses and sinks to the bottom where it can't evaporate. Wide temperature swings combined with warm moist air exacerbates the problem.

If you remove your reservoir (perhaps get an "O" ring to have handy in case the old one is rough) you may find that there is ice built up on the inlet and outlet screens. Clean them with a brush, and clean the magnet in the can while you are in there.

There may be rust on the reservoir "can" that prevents the O ring from sealing properly.

I'm sure there are other ways for moisture to get in, but that's where my problems have come from.

 

John
Sorry you are having a problem. BOSS plows are usually not having issues like this but i think i can help. Moisture is usually caused by heat in the hydraulic system and when it gets hot it is coming in contact with the cold air (since it is not in direct contact wit snow like Stargazers Fisher) How old is you plow? If the pump is getting weak and it is getting the oil too hot and breaking it down it can draw moisture (not water)through the vent and it will condense in the hot oil. The wayer you found in the lift cylinder could be residual from when the moisture was in the system

 

Moisture is usually caused by heat in the hydraulic system and when it gets hot it is coming in contact with the cold air (since it is not in direct contact wit snow like Stargazers Fisher)

I'm curious what you mean by "in direct contact with the snow". It seems to be a closed system except for the air breather. All outdoor air contains moisture, which condenses if the air is cooled enough.

If that is the only problem, it is not moisture. Sounds like it is low on oil with both angle cylinders fully extended IMO.

~Chuck

I agree. I have however had the symptom of starved for oil be caused by the screens being plugged with ice. This takes a lot more than 20 hours, more like a year.

 

Thanks for the information both of you. I'm not blaming the Boss design, as I've had nothing but good service from 3 others, and this unit in every other regard. It is a 2006 plow, and has had this issue since new. The 2007 model I sold off this last fall didn't and still does not have the isse (I sold it to my best friend, so I am still maintaining it as he is new to plowing and, as a career government pencil pusher, will soon know the difference between some of the tools in the toolbox - but that's another story ........)

I am using Esso J-13 oil from a 20 litre pail. I haven't brought that oil to 212 degrees to ensure there isn't water in the oil, but I will next with my candy thermometer.

 

It may not necessarily have water in the oil in the pail. If the pump is slipping or the screens are partially plugged or something and the oil is getting extremely hot and forming condensation in your reservior and then building up enough to be come water is what i was thinking but it could be coming from the source. You can have your pump pressure checked to see if it is coming up to specification (a vee dead heads at 2500 lbs) to get an idea of the health of your pump.
Does your old oil smell burnt?
Is your old oil dark and discolored?
Is it actually "milky" from water intrusion?
How long does it take from a fresh flush and change before symptoms re-appear?

 

Thanks for the interest John. To give you more info, I figured that the pail of oil may be a source, as it has been open for two years now - it takes me a while to pass 20 litres through the pumps, but the oil pours off the top and and water would be on the bottom. I figured that ensuring "dry" oil wouldn't hurt .

The old oil isn't burnt, milky nor discoloured, infact I recycle it into my oiling can for penetrating oil as it is pretty light.

From a fresh flush to symptoms is typically about 20 hours of plowing. I don't think the pump overheats, as I am typically plowing in -10 to -20C (just above 0 degrees F). Is it likely that the wiper seal on the lift cylinder is allowing moisture to pass? Should a repack of that cylinder be considered?

 

If it is not milky, it is not likely moisture. One other thought though, is that the (insert brand here) oil has alcohol in it to prevent freeze ups. Not shaking the large can you have had for so long, maybe the alcohol seperated and it too is near the bottom of the pail? A long shot, but possible. Moisture is usually pretty easy to see when you drain the fluid. Drain the fluid into a clear jar/bottle and let it sit a week or so, and the water will go to the bottom slowly if it is there.

~Chuck

 

I am still getting moisture issues in that the plow will not lift when in full scoop mode - it will chatter in the hydraulics. Once the oil is refreshed, that symptom goes away.

If that is the only problem, it is not moisture. Sounds like it is low on oil with both angle cylinders fully extended IMO.

~Chuck

 

John
When you flush it this time buy 4 quarts of new oil and give it a shot. I don't trust oil that has been opend that long and as Chuck said, make sure the fluid is Full becaused the chattering is a definite sign of low oil with both wings extended

 

Thanks again guys. The oil level isn't low, as I have repeated this flush just months apart for 3 years now. The system is still like new, and there are no leaks. Perhaps the oil has separated.

What I did notice last night plowing (at -13 degrees C, which must be 3 or 4 F) is that it will do this chatter only to a certain point, say when the blade reaches 10-12" off the ground, then it stop chattering and will speed up and go the rest of the way up without complaint and at full speed. This is with just one push of the Up button.

Stargazer, when I mentioned the lift cylinder is in the snow, it is because the Boss inverted chainless cylinder is in the snow when backblading and the snow boils up behind the plow. I figure that a warmed up cylinder rod from the hydraulics would melt some snow, and that water would sneak past the seals on the cylinder and into the system when the plow lifts. Other than the oil separating as Chuck suggests, I see that as likely.

When this first became a big enough problem two years ago that I pulled the cylinder apart, I found water droplets on the walls of the lift cylinder. They had not turned the oil milky. I'm thinking that the water will make the packing stick inside the cylinder down low, where the water would settle, and not bother it so much higher in its lift stroke. I don't know, but its what I figured based on how it acts and what I saw upon disassembly. That brings me to suspect the wiper seal. ??

 

I know you keep thinking it might be the wiper seal but honestly it would be the first one i have heard go bad unless the rod got bent or the oil seal blew

 

Isn't the chattering in Johns case from the filter getting plugged with ice crystals and therefore not allowing enough oil to the pump. I've had that happen to a couple Eblings this year. Worked fine when warm but chattered alot when really cold. A little gas line antifreeze will fix it but some people don't recommend it.

 

A little gas line antifreeze will fix it but some people don't recommend it.

I wondered about that too - a small dose of methyl hydrate should take care of any moisture issues, just wonder what the "side effects" would be.

 

On Jerre's advice, I added a tablespoon of isopropyl to our western when it was icing the filter. No problems after that.

 

I'll give it a little shot of methyl hydrate to get me to March 31st. It will get its teardown then. I'm glad John that in your experience, that seal doesn't present a problem. Thanks everyone.