425 again…movement problems…

[Modrob]

Depending on the control system you have, they all can go out of alignment.

As @m5040 mentioned a certain amount of whining at low oil temperatures is to be expected to happen due to higher oil viscosity, but try to minimize it by letting the oil warm up. I believe that @MossRoad starts his and lets it run for a while (15 min?) while he does some hand shoveling. If your pump is not in trouble, the whining sound is the oil cavitation as it is being pump and the cavitation is very hard on, and damaging to, surfaces.

All the best,

Peter

Thanks again. I started reading about cavitation. One site mentioned this, concerning viscosity and cheap to expensive fluids:
“Therefore, most hydraulic systems should not be started up with the oil any colder than 40°F and should not be put under load until the oil is at least 70°F.”
Wow! The article was dealing with factory-type equipment and systems but I believe some of it extends to our equipment…

 

[ponytug]

Thanks again. I started reading about cavitation. One site mentioned this, concerning viscosity and cheap to expensive fluids:
“Therefore, most hydraulic systems should not be started up with the oil any colder than 40°F and should not be put under load until the oil is at least 70°F.”
Wow! The article was dealing with factory-type equipment and systems but I believe some of it extends to our equipment…

It does, and it may/is probably one reason why Power-Trac recommends 10W40/15W40 instead of the usual 30W hydraulic fluids used inconstant temperature settings like factories. Some other tractors with hydraulics actually have heaters, electrical or diesel powered, to warm the oil before the tractor can be operated.

Eberspacher is a well known brand of diesel fuel heaters used to heat trucks and heavy equipment. They are high quality, but it does take time to warm hundreds of pounds of metal and oil... Here a video of a creative guy, living north of the arctic circle on the Sweden/Finland border installing one in his excavator;

All the best,

Peter

 

[Modrob]

It does, and it may/is probably one reason why Power-Trac recommends 10W40/15W40 instead of the usual 30W hydraulic fluids used inconstant temperature settings like factories. Some other tractors with hydraulics actually have heaters, electrical or diesel powered, to warm the oil before the tractor can be operated.

Eberspacher is a well known brand of diesel fuel heaters used to heat trucks and heavy equipment. They are high quality, but it does take time to warm hundreds of pounds of metal and oil... Here a video of a creative guy, living north of the arctic circle on the Sweden/Finland border installing one in his excavator;

All the best,

Peter

I was adding yours and more info to my ongoing file and reread MossRoad’s details and pic about hydro back. It seems I didn’t remember, but it appears the only adjustment would be the cylinder and mount that can be slid in its bracket. Since I had lifted the unit on all fours and found no movement when started, and the pedals operated as they should, then there really isn’t any more adjustment. So I believe I can rule any simple adjustments out. I’ll be out of town for several days but when I return I’ll start digging deeper into the cavitation route….

 

[ponytug]

I was adding yours and more info to my ongoing file and reread MossRoad’s details and pic about hydro back. It seems I didn’t remember, but it appears the only adjustment would be the cylinder and mount that can be slid in its bracket. Since I had lifted the unit on all fours and found no movement when started, and the pedals operated as they should, then there really isn’t any more adjustment. So I believe I can rule any simple adjustments out. I’ll be out of town for several days but when I return I’ll start digging deeper into the cavitation route….

Not a lot to be done about cavitation; slow the engine speed down, especially when cold, don't work it had while cold, and possibly change the hydraulic oil to fresh 10W40. How does the hydraulic oil look? Do you know when it was last changed, and what oil was used?

If the pump is worn it may be more prone to cavitation and there isn't much to be done about that.

All the best,

Peter

 

[Modrob]

Not a lot to be done about cavitation; slow the engine speed down, especially when cold, don't work it had while cold, and possibly change the hydraulic oil to fresh 10W40. How does the hydraulic oil look? Do you know when it was last changed, and what oil was used?

If the pump is worn it may be more prone to cavitation and there isn't much to be done about that.

All the best,

Peter

I did a change probably little more than a year ago, and filter. But it’s only been run maybe 10 hours since then. Still looks good. I can’t recall the exact oil but I followed recommendations from folks here.

 

[ponytug]

I did a change probably little more than a year ago, and filter. But it’s only been run maybe 10 hours since then. Still looks good. I can’t recall the exact oil but I followed recommendations from folks here.

Great! Was there any sludge in the bottom when you drained the old oil? Particularly anything magnetic?

I may have mentioned this, but one other item that can cause some cavitation is an air leak at the suction filter. The easiest way to check that is to run the tractor for a bit and then look in the hydraulic tank with the engine running (with the brakes on!), and check for bubbles or foaming.

All the best,

Peter

 

[oldnslo]

Mobile equipment if designed properly can and will operate well below 40 degrees F. This becomes a factor of pump inlet conditions like hose diameters, lengths, etc. along with oil viscosity.

If you are having issues with cold weather starts maybe consult with manufacturer to see if there is an option for lower viscosity oil like 5W-40 for colder climate vs 15W-50 for warmer climate. What is your ambient temperature in summer since you also need to consider that when selecting hydraulic oil for your equipment.

 

[m5040]

IMPORTANT, people with the hydroback cable to control fwd/rev on the Powertrac must make sure the connections throughout the control "chain" are in good condition. Especially the arm pined to the hydrostatic pump. If the pin was partially sheared, it would limit the travel from the foot control, and if you keep using it, the pin would shear, and you would have no way to control the drive system other then kill the engine. To check, closely watch the shaft on the pump as the treadle pedal is cycled. If you see any movement in the arm without corresponding rotation of the shaft, check/replace the pin that secures the arm to the shaft.

Also cavitation of a hyd pump can come from leaks in the suction side (from hyd pump intake to reservoir). A "leak" might not actually lose oil, (air is thinner than oil), but could allow air to enter the oil stream when the pump is drawing in cold-thick oil. The air causes the noise and damages the pump internals.

 

[ponytug]

Mobile equipment if designed properly can and will operate well below 40 degrees F. This becomes a factor of pump inlet conditions like hose diameters, lengths, etc. along with oil viscosity.

If you are having issues with cold weather starts maybe consult with manufacturer to see if there is an option for lower viscosity oil like 5W-40 for colder climate vs 15W-50 for warmer climate. What is your ambient temperature in summer since you also need to consider that when selecting hydraulic oil for your equipment.

While this may be generic advice, it does not apply to these machines.

It is worth examining an oil viscosity chart for the data.

There is almost no difference in cold weather viscosity between 10W40 and 5W40, and the exact same viscosity at higher temperatures. (The two columns on the right are cold, then high temperatures viscosity. A 10W40 oil might be 120SUS cold, and 70SUS hot, while a 5W oil is closer to 95SUS cold.

@Modrob don't use less than 10W40, per the factory. (And great advice from @m5040)

All the best,

Peter

 

[oldnslo]

Not trying to start a war but what makes a power trac hydrostatic drive any different than a skid steer or any other hydrostatic driven vehicle?