Bobcat 763 No lift when cold

[bob763f]

I posted this in the Bobcat forum as well but thought I would try here as well since this is Hydraulic specific. A month ago I purchased a "new to me" bobcat 763F. It has 2500 hours on it. About a week ago the machine stayed outside over night and the temp got down to 15*F when I came out in the morning the machine started with no issues, pulled lap bar down and pushed the unlock button. The machine will move forward and backwards and bucket will tilt in both direction but will not lift. When you move the lift pedal you can hear the engine get a load on it and hear the line pressurize but it wont lift. After letting run and warm up for about 15 min everything worked fine and no more issues. This morning we 17*F and I have the same issue. I have done some research all over youtube and google and not finding any help. The machine does not have the boss system, it is handles and foot pedals, it has a new hydro filter and good clean fluid that is topped off. Any help or guidance is appreciated.

 

[grm61]

I posted this in the Bobcat forum as well but thought I would try here as well since this is Hydraulic specific. A month ago I purchased a "new to me" bobcat 763F. It has 2500 hours on it. About a week ago the machine stayed outside over night and the temp got down to 15*F when I came out in the morning the machine started with no issues, pulled lap bar down and pushed the unlock button. The machine will move forward and backwards and bucket will tilt in both direction but will not lift. When you move the lift pedal you can hear the engine get a load on it and hear the line pressurize but it wont lift. After letting run and warm up for about 15 min everything worked fine and no more issues. This morning we 17*F and I have the same issue. I have done some research all over youtube and google and not finding any help. The machine does not have the boss system, it is handles and foot pedals, it has a new hydro filter and good clean fluid that is topped off. Any help or guidance is appreciated.

Water/moisture........No problems above freezing?

 

[bob763f]

I had my son try it a few minutes ago. It is sitting in the sun at 36*f right now and still has no lift. When I get home if I let it run for 5 min or so the lift will start working. Wouldn't water work its way to the filter and collect there?

 

[oldnslo]

If pressure is building when you operate the valve with your foot this would indicate something else is blocking the flow to the lift cylinders.

I do not know what bobcat has installed for safety features but suspect there is a safety device possibly a valve that is sluggish in cold oil.

Do you have a hydraulic schematic for this.

 

[laurencen]

just throw it out, our 743 when outside well below zero is sluggish on lift and tilt until it warms up, never had the issue until we drained the oil and filled it with motor oil, the manual suggests oil from bobcat or motor oil, obviously motor oil is thicker in cold, may be your problem

 

[bob763f]

just throw it out, our 743 when outside well below zero is sluggish on lift and tilt until it warms up, never had the issue until we drained the oil and filled it with motor oil, the manual suggests oil from bobcat or motor oil, obviously motor oil is thicker in cold, may be your problem

What are you using for hydraulic oil now? Where I am it may get down to single digits every now and then, most lows are upper teens and twenties. I tried it this morning and it worked fine. It was 26*f last night. So it seems to be of how cold it is rather then below freezing or not.

 

[oldnslo]

This is not an oil flow to the pump problem Since your tilt function was working and you could also hear the pressure build when you operated the lift valve.

 

[laurencen]

we still use engine oil and warm it up before using, we get temps down in the -30 regularly, pressure builds but moves sluggishly until warm

if you look at the hydraulic lines are both pressurizing? is both up and down sluggish?

 

[laurencen]

we still use engine oil and warm it up before using, we get temps down in the -30 regularly, pressure builds but moves sluggishly until warm, we find the tilt appears to work better but it uses less oil to get same movement as the cylinder is single and smaller in diameter

if you look at the hydraulic lines are both pressurizing? is both up and down sluggish?

 

[bob763f]

we still use engine oil and warm it up before using, we get temps down in the -30 regularly, pressure builds but moves sluggishly until warm, we find the tilt appears to work better but it uses less oil to get same movement as the cylinder is single and smaller in diameter

if you look at the hydraulic lines are both pressurizing? is both up and down sluggish?

The tilt works at normal speed. The lift wont move at all until the machine runs for about 5 min then it works at normal speed. When it is not working if you try to move the lift pedal you can hear it put a load on the engine and here the line pressurize but nothing moves.

 

[laurencen]

by chance the oil blowing past the seals in the lift cylinder? does it lift a load when it does work? you need to get hold of a hydraulic diagram and see if the lift system have a relief valve, this may need adjusting

 

[geekbstrd]

This is an old thread but I have the same problem with a Bobcat 773. I changed the hydraulic oil and filter. It seems to be a solenoid valve that is not opening. As the OP stated, i can hear the pump and engine load up when I actuate the lift. Some valve is blocking it. If I let it warm up it works.

 

[Dman1981]

ATF for cold weather
Works great
Works good in summer to
Used in the desert kept valves from sticking when it was 120 outside

 

[flyerdan]

One thing you might look at is the emergency lift lowering valve; it could have some effect on this. Seems like a likely suspect as drive and tilt work okay, and it's not part of the normal operating envelope.