Loader "float" freeze-up in winter

[Dr. Bob]

Could anyone advise me on this problem with my B7800/LA402?
When the temperature is below freezing, It is either difficult to get the loader control into the float position or if it goes in it will not lock in the float position (I have to hold it there). My suspicion is that there is a little water in that part of the system and it is freezing. In fact, if I take my wife's hair dryer (with her permission, of course!) and heat it up, it will work. But once it is shut down and sits in the freezing weather for a while, the problem reappears.
Any suggestions? The tractor is coming up on its 300 hr service that requires changing the hydraulic fluid. Is there anything special I should drain during that operattion?

 

[bigdad]

Check out the many threads on loader float freeze-up. It's an easy fix.

 

[johnk]

I think you have water in the valve. I had the same problem with mine when it was under warranty. They replaced it with one with a hole in it so the water drains.

 

[john_bud]

Agree, water is your enemy.

The side of the valve opposite the handles has a cap. It unscrews. You should do that and clean it out. There probably is a vent in the cap, but it also probably has been painted over and is no longer a vent!

Try to take the paint off the end of the cap with paint remover. The vent is usually expanded (foamed) metal like a sponge and is easy to clog up. If there never was a vent, you can drill a 1/32 hole. Just test fit it and mark where the bottom will be and drill there.

It's also possible that there is some water in the oil that is freezing. Next time you change hydro oil, extend the loader cylinders all the way out for both boom and bucket. Drain the oil, then float the boom down and muscle the bucket around so it will also retract. That will get more of the fluid out. Then fill with clean fluid. It's not unheard of for water to accumulate in loader cylinders. Mostly in tractors that are infrequently operated.

 

[7800DUDE]

I also had that problem when under warranty they also put a one with a hole in it an solved the problem.

 

[Killer_B]

I also had that problem when under warranty they also put a one with a hole in it an solved the problem.

Ditto my B7610, except it was out of warrantee. Easy fix, though.

KB

 

[Egon]

I have had that problem the odd time. Usually running the tractor and getting the oil warm in the hydraulics has nullified the problem!

 

[638]

If the oil is not milky looking, there is not any water in the oil.

ron

 

[N1ST]

Anyone know when abouts they made the drain hole part of the production tractor?

 

[rbargeron]

When the valve spool moves back to the float position it displaces a small amount of air in the back end of the valve. If the oil is too cold it's too viscous to let the air flow forward around the spool to relieve the pressure. The trapped air acts as a spring, pushing the valve forward from the float position. I use a bungee to hold the valve handle in the float position. Once the oil warms up a little, the valve will stay in the float position by itself. I think the "drain" hole is really there to vent the air out.