Loader Control working funny

[RichK]

Greetings,
I have a L2500 with LB400 loader. It won't go into float anymore, it used to with difficulty but now it won't. Actually it seems that "dump" (to the right) does have a float. It moves to a stop and then with a little extra effort it clicks farther over. But pushing the control straight up doesn't drive it into float. The other part is when I lower the loader, if I try setting it on something to smooth it, the loader will tilt up like there is no force holding it rotated down in dumped position. If I tell it to rotate down, I can get it to lift the front end.
Is the control lever broken somehow? What can I do to fix it. The tractor only has 220 hours on it and most of those were mowing. Lately I've been doing more dirt moving and found this working funny. It also seems like when I hit a bump, with a load in the bucket, it bounces up like its only held up and not down. Is all this normal?
Thanks.
Rich.

 

[PeteF]

Sounds like there is air in the system. Try excersizing the full range of motion with no load. It may also be that your system is low on hydraulic fluid (a bad thing).

B2710/LA401/4690

 

[MChalkley]

RichK - It sounds like you have two separate problems, though I'll admit that's pretty unlikely. Still, I don't think there's any other possibility, if I understand the symptoms correctly.

First, the float problem. I notice from your Bio that you're in WI. Was it below freezing when you tried it last? If so, you've got water in the end cap of the loader raise/lower spool. If not, you've probably got a detent ball jammed. There's a long discussion in the archives of the old board about this. You might do a search on "balls" to find it - seriously. It'll tell you how to take the end cap off and check out the problem. If you can't find it, holler back and we'll go through it again.

The other problem you mention indicates you may have air in the system or a leaky valve. As Pete mentioned, you may be low on fluid. If you place the bucket on the ground, and force the bucket to dump, will it rais the front of the tractor off the ground? If so, you've forced the air out of that side of the cylinder. If you roll the bucket all the way back and hold it until the engine loads up a little, you've forced the air out of that side, too. If the problem of the bucket moving as you set it down still happens, you've got a leaky valve, leaky cylinder, are low on oil, or have a clogged intake filter on the hydraulic pump which is causing the pump to cavitate and eventually will destroy it. In short, there's something wrong and you shouldn't waste any time getting it fixed.

MarkC

 

[TomG]

I won't add to Mark's diagnostic comments. However, I note that the control valve that has a longer body than the others is the one with float on it. The hoses on my used tractor were set up so the bucket floated. Seems odd, but I hear that tractors used for haying sometimes are set up with a floating bucket. I simply swapped the bucket and lift hoses.

 

[RichK]

Hello again. Sorry it took me so long, my son was using an old Craftsman (there's an oxymoron for you) garden tractor and pulled a swing set over on his head. All's fine but now I have more to do.
I took apart the control valves to check the detent balls and springs. They were all gummed up with dirt and grease or something. Cleaned them up and now I can at least get into float, although it is pretty stiff. Checked the trans fluid levels and it shows a little under half in the glass. Seems to be real sensitive to how level the machine is. Also doesn't help to try to check it when it's running, climbs right up and appears over-full. Haven't been able to pull the screen out to see if it's blocked, the rest of the loader controls work normally though. I noticed someone had problems with the hoses going to the wrong spot. Tried to check it, and all were right except two that I really couldn't verify. The book says there should be a block on the front under the seat near the lift speed control (??) that has two hoses on it. This system has a block on the right side attached over where the power steering assist comes off the trans and it has the two hoses. Anyone else have an LB400 that can tell me where those two hoses are attached to? The book is different and I tried looking at the shop manual for the tractor, but it doesn't show attachments. One hose has an orange sticker on it but I didn't see a dot one the control. Maybe I just missed it. Anyone else have trouble with the paint dots fading so you can't tell the colors?
Thanks again. Rich.