440IC single spool hydraulic valve issues

WWoods · Post by **WWoods** » Mon Sep 16, 2013 4:13 pm

I have a 440IC that my father bought a number of years ago. I've been having to learn how to do the repairs over the last couple of years do to his physical and mental health. It has been a new, and pretty interesting (while also frustrating) experience.

The latest of the issues is that when I go to raise the plow it will act like it is trying to raise but just doesn't have the capability. both arms will jerk like normal but the cylinders won't contract. After a while of playing with it it will sometimes begin working and continue to work but will seep down constantly. The motor doesn't ever sound like it is working hard when this happens. I've noticed a small leak off and on from the back of the spool on the valve, but not sure when it is leaking. It is a small leak.

pushing the blade down will lift up the front of the crawler and will hold it up without issue. The only thing I notice when pushing it forward is a sound (not sure how to describe it off of the top of my head) coming from the valve, almost like the valve is working really hard to do its job.

After it started to happen I replaced two hydraulic lines that were getting pretty bad, as well as replaced all the fluid and added Lucas hydraulic treatment. Nothing has improved yet (though I suspected it wouldn't).

I was looking in the service manual and saw that the spool doesn't have many seals associated with it and that is is just a tight fit and that is what prevents the leaking into *not at that moment* used chambers. Is the most likely case that the spool has gotten worn down and when I pull it back to raise the blade it is leaking so much internally that the blade can't lift? or is it possible that one of the springs/balls in the unit is damaged/not working? I tried to follow the flow diagrams in the manuals for where fluid would go in what situations but kept getting lost when trying to figure out how this fail would look.

If anyone has any suggestions on what might be happening or the best way to go about figuring it out that would be wonderful.

Thank you.

original possum · Post by **original possum** » Mon Sep 16, 2013 6:04 pm

Some of the 440's (that had reservoirs behind the grill) used nylon (or hard plastic) check balls in the control valve. When they wear they can plug the line. If they wear more they can get into the suction line of the pump and total it.

scampr · Post by **scampr** » Mon Sep 16, 2013 7:08 pm

Since the down pressure works it sounds to me like the pump and flow are ok??? Sounds to me like a seal on one side of the spool valve or the valve itself I had a spool valve actually break on a 440 loader i had years ago . Was actually easy to take apart and fix, but in those days the dealers had parts..now i dont know. good luck

Post by **Lavoy** » Tue Sep 17, 2013 8:04 am

Blade falling is normally cylinder seals, jerking is low fluid, or air leak most likely.
Lavoy

WWoods · Post by **WWoods** » Tue Sep 17, 2013 6:46 pm

Looks like I should take it apart and check out the springs and the scoring on the spool. I will attempt that later this week and hopefully it is something simple.

Post by **Lavoy** » Tue Sep 17, 2013 7:09 pm

Spool is the last place I would look.
Lavoy

WWoods · Post by **WWoods** » Tue Sep 17, 2013 7:13 pm

Could it be the seals in a cylinder even though it lifts the crawler up and holds it there without a problem?

Tigerhaze · Post by **Tigerhaze** » Wed Sep 18, 2013 9:16 am

I would second Lavoy's opinion about air in the system being at least part of the problem- the jerking while lifting and noise is what my 2010 loader did before I bled it after changing out the hydraulic line. Did you go through the bleeding procedure?

Post by **Lavoy** » Wed Sep 18, 2013 9:36 am

Yes, two different cups, one for down, one for up, seen it many times.
Lavoy

WWoods · Post by **WWoods** » Thu Sep 19, 2013 7:38 am

Tigerhaze wrote:I would second Lavoy's opinion about air in the system being at least part of the problem- the jerking while lifting and noise is what my 2010 loader did before I bled it after changing out the hydraulic line. Did you go through the bleeding procedure?

I thought I read in the manual that you just need to work the system back and forth and that would bleed the system. Was there something else that I had missed?

WWoods · Post by **WWoods** » Thu Sep 19, 2013 7:40 am

Lavoy wrote:Yes, two different cups, one for down, one for up, seen it many times.
Lavoy

Lavoy do you happen to have the cups for sale for the dozer (non 6 way) that came on the 440IC? And would it be a good idea to replace them all at this time or is it a case of 'if they are working leave them be'?

Tigerhaze · Post by **Tigerhaze** » Thu Sep 19, 2013 1:47 pm

WWoods wrote: I thought I read in the manual that you just need to work the system back and forth and that would bleed the system. Was there something else that I had missed?

That is the procedure as I understand it, although it won't necessarily bleed after moving it back and forth a few times- you may need to do it up to a dozen times. On my 2010 loader, it takes many cycles of up/down/curl out/curl in to get the air out after a major leak. I just wanted to make sure that you knew that the blade would need to be worked in all directions multiple times to get the air out.

If you still don't have improvement then it points to the other issue that Lavoy mentioned (air leak to the hydraulic system due to loose hose connections, etc.). While the internal packing seal may affect leakdown, I wouldn't think they would be the reason air is in the system.

Post by **Lavoy** » Thu Sep 19, 2013 2:30 pm

Unless a hose has been replaced, air is likely on the suction side somewhere.
I might have cups on hand, if not, easy to get. Unless you can isolate the cylinder that is bad, you will need to do both.
Lavoy

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440IC single spool hydraulic valve issues

440IC single spool hydraulic valve issues

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