need help with loader control

varmint · Oct 20, 2005

Well, I finally have to come begging to TBN for some help! I got my trusty Kubota B8200 out last night after the plumber and his backhoe left, having done a septic line tie in and leaving a jumble of soil to be smoothed out, only to discover the loader was boogered! I don't think the hydraulics per se are the problem, since the power steering and the three point hitch work normally, but the loader (a Bush Hog QT840) goes up fine, curls one way fine, but doesn't want to down or curl the other way. When you put the control in float, the bucket goes up! Which makes me think the control valve is acting up. Now what? Can I take it apart and look things over, or is it something that needs professional experts? (I "rebuilt" a VW's fuel injection distributor some 30 years ago, and it almost ran after the third time- to be fair, my shop guys told me it couldn't be done, and the o rings weren't available anywhere). Thanks to those who have tread the path before me. Varmint

MadReferee · Oct 20, 2005

Check the joystick linkage. I'll bet you have some crap in there that is screwing up the linkage where it attaches to the spools.

RobS · Oct 20, 2005

What Mad said plus check your connections. Have you had the loader off recently? Make sure each connection is the right pair and that they're fully seated. Hope you get'er straightened out /forums/images/graemlins/smile.gif

varmint · Oct 20, 2005

I haven't touched the connections or anything else concerned with loader for quite a while- and everything worked just fine about a week ago. I suspect the control valve since it works fine in about half the modes. Nothing obvious is wrong. I'll get back when I have time to check better. thanks.

MadReferee · Oct 20, 2005

The symptoms you describe would not be related to a spool internal malfunction unless the end cap or handle cap has come loose and the spool rod itself is no longer properly seated. This should be easy to see without much, if any, disassembly.

I will still place my money on a linkage problem, either loose or impeded by some form of trash.

KubotaSteve · Oct 20, 2005

I had a problem similar to this on my 7800 and I had left the 3pt hitch lever up (pumping) and the loader would raisee and curl up but would not go back down or curl down. My 7800 has the 1/4 inching valve instead of position control (not sure if that makes a difference or not). Just thought I would throw that out there.
Good luck

Egon · Oct 20, 2005

That could easily be the problem Steve.

Egon

varmint · Oct 21, 2005

So far, I did check the connections and joystick linkage, all of which were fine and normal. I called Bush Hog, and they think it may be a valve issue... I will check out the 3-point issue, since I had just removed the rear blade and installed the auger, and moved up and down a bit in the process, but I have a position control, and I don't think it would create such a problem.

koykermfg · Oct 21, 2005

It sounds to me that you have a back pressure problem. If you lower your three point the loader should work fine. To make it work right all the time you would need a valve that offeres power beyond. You may want to contact the loader MFG and ask if they offer a Power beyond setup for the valve you have. We have seen this problem before and it's usually because the loader valve is hooked up infront of the three point. If you don't raise your three point all the way (keeping the 3 pt valve open), your loader should work fine. Let us know if this info helps. Thanks

varmint · Oct 22, 2005

Thanks for the ideas: and keep in mind that the present set up has worked just fine for years. After talking to the Bush Hog tech guys (who were really helpful and easy to deal with, to their credit) it is determined that the seals in the valve are shot, so I have a rebuild kit on order. I will let everyone know how this evolves.