PT 1430 Hydraulic Trouble

[KentT]

Engine oil has one place, a engine.

Can you then explain why Parker-Hannifin tests and records the performance of their hydraulic wheel motors using 10W40 oil? Seems at least one manufacturer doesn't agree with you...

 

[J_J]

One other item I forgot to mention from the hydraulic shop was the owner told me if the wheels on the machine are lifted off the ground, a good indication of the condition of the wheel motors is whether a wheel is easy to rotate. I did this with my machine and they are very easy to turn. If the motors were alright, the wheels should be more difficult turn. Does this make sense?

There is some merit to what the owner said about turning the wheel motors. The only good way to test the wheel motor is to take it to a hydraulic shop and have them hook it up and try to stall it. If it holds pressure, the motor should be OK. The hydro technician might be able to tell you you the state of the motor, by how much fluid is leaking internally.

If you have one wheel jacked up, and you can turn the wheel fairly easy, there is a problem. This is true only if there is no leakage back through the system. Your wheel motor is acting like a pump. If you have all wheels off the ground, engine not running, and you turn one tire, does any other wheel turn? As I have said before, when I have both front wheels off the ground, and I turn one wheel, the other wheel turns in reverse. One wheel is acting like a pump, and the other wheel motor is motoring in reverse. Strange, but true. That front linkage on the tram cable has some adjustment and should be tight. The swivel joint may be worn out.

 

[menchhofer]

I have replaced the swivel joint today and the problem remains the same. I suspect the cable now but am not quite sure. Terry said the cable could be at fault but this is the second one and the machine only has 440 hrs on it. Do they wear out quickly? At $135 a pop I would think not but I assume it could.

 

[DieselPower]

Can you then explain why Parker-Hannifin tests and records the performance of their hydraulic wheel motors using 10W40 oil? Seems at least one manufacturer doesn't agree with you...

Because it's cheap and easy to get. Just because something works does not mean it's the best thing for the application. Let's look at the reverse. Would you run hydraulic oil or UTF in your engine? Probably not. The additive packages of engine oil and hydraulic oils are very different. The hydraulic oil or UTF is going to have a much higher level of zinc (with UTF having about 2X that of hydraulic oil on average), higher levels of anti-foam additives and usually is formulated for better water demulsability then engine oil.

 

[menchhofer]

He would be correct, engine oil does contain additives not found in hydraulic/utf type oils. Problem is the additional ones it does contain have no purpose except in a internal combustion engine. The anti-wear additives can be as high as 4-5 times higher in a UTF fluid then what would be found in a engine oil along with higher levels of anti-foam and friction modifiers. Engine oil has one place, a engine.

I have also owned wood chippers throughout the years and they also run 10w-40 in the hydraulic system and specify the oil is to be used in the machines when replacing the fluid. So for now, I continue to be confused regarding which oil is best in a hydraulic system. I assume the manufacturers would know best.

 

[woodlandfarms]

I have replaced the swivel joint today and the problem remains the same. I suspect the cable now but am not quite sure. Terry said the cable could be at fault but this is the second one and the machine only has 440 hrs on it. Do they wear out quickly? At $135 a pop I would think not but I assume it could.

Can you test it without the cable. Sorry, I don't know your cable system, but there has to be a way to give it a tug at the source...

Carl

 

[KentT]

I have also owned wood chippers throughout the years and they also run 10w-40 in the hydraulic system and specify the oil is to be used in the machines when replacing the fluid. So for now, I continue to be confused regarding which oil is best in a hydraulic system. I assume the manufacturers would know best.

Amen to that. BTW, here's a couple of pages of the Lube info for Simplicity lawn & garden tractors over about a 30 year span. See all the different ones that specify motor oil. Some specify hydraulic oil.

New Page 2

Lube (pg2)http://www.simpletractors.com/service/lube_pg2..htm

Interesting that someone trying to sell something knows more than the engineers who built it. To say "one size fits all" in disregard to the manufacturer's recommendation is pure ... well, I won't go there.....

 

[KentT]

Because it's cheap and easy to get. Just because something works does not mean it's the best thing for the application. Let's look at the reverse. Would you run hydraulic oil or UTF in your engine? Probably not. The additive packages of engine oil and hydraulic oils are very different. The hydraulic oil or UTF is going to have a much higher level of zinc (with UTF having about 2X that of hydraulic oil on average), higher levels of anti-foam additives and usually is formulated for better water demulsability then engine oil.

No, I wouldn't. I don't put 90W gear oil my engines, nor do I replace 90W gear oil with hydraulic oil (regardless what additives it might have), nor do I replace it with motor oil. I'd run what the manufacturers recommend.... and there is at least ONE of the wheel motor manufacturers, Parker, who tests their engines with motor oil, and approves it for use. I think a second one (White) also uses motor oil, based on SUS ratings, but I'm not sure. Char-Lynn approves it for use, though they apparently test with hydraulic oil, based on the lower SUS ratings specified.

Point is that some applications recommend hydraulic oil, some don't. Some are designed to operate with the lower viscosity that hydaulic oil has, some apparently aren't. Their specified service life (i.e MBTF) would be based upon the lubricant that THEY recommend...

IMO, arbitrarily changing to hydraulic oil, despite the manufacturers recommendations, would make just about as much sense as running Dextron in your car engine, despite the manufacturer recommending engine oil...

 

[MossRoad]

Can you test it without the cable. Sorry, I don't know your cable system, but there has to be a way to give it a tug at the source...

Carl

Yes, he can put the unit up on jacks so the wheels are off the ground, then operate the lever manually that the hydroback assembly activates by cable when stepping on the direction pedals.

 

[DieselPower]

Nowhere did I say one size fit's all. I'm not trying to start a argument. Just my input from the lubricants side of the argument.

Don't forget that hydraulic oils can be had in many more viscosity's than engine oils. You can get anywhere from a ISO 10 (lower than SAE 0W engine oil)all the way up to a ISO 1000 (about SAE 250 gear oil) and can also get them in the multi-viscosity variety.

My point is that you can get a oil in comparable viscosity that is actually designed to be used as a hydraulic oil. Not something that was designed to be something else, a engine oil. The hydraulic oil will perform better, operte cooler, last longer and reduce wear better leading to longer equipment life. Does the engine oil work as per equipment manufacturers spec's, sure it does but there is spec and then there is better than spec.

You also have to look at it from the equipment manufacturers point of view. Engine oil is readily available for anyone to find. Odd ball viscosity hydraulic oils usually have to be ordered. Joe down the street needs to fill up his equipment on a Sunday, the engine oil can be purchased at the corner auto parts store instead of having to order the oil and wait a couple of day's for delivery.

Besides, if equipment manufacturers design and spec their stuff to high it will never break and they will never sell any replacement parts.