Fixed Loader Joystick Control Valve

May 9, 2014

This is just a story of personal satisfaction and financial savings I wanted to share.:DI have been grading and using my loader and rear blade on my AGCO ST25 in preparation for a tent garage building to house my AGCO, garden tractors, implements, and misc equipment.:DA few weeks ago I began having some loader problems. It began to have a mind of its own. The boom would rise without notice. Kind of dangerous. :OIn addition when I would move the joystick left instead of curling the bucket it would raise the boom. :OAlso, I could not get the joystick into the float position, and regeneration dump was sporadic. :OAll this was a little frustrating, as I have not done much prior with hydraulics. I have been under pressure with loads of work and projects, and I really did not need anything else on my plate. :OI started pricing new valves. :OThe original is a Nimco 422, AGCO dealer price $1200., distributor price $650.00. !I priced after markets anywhere from $300-$500. CThe good news is I fixed the valve without a hitch, no out of pocket cost, and only about 2 hrs of stress-less labor. I wish all jobs went this well. :DI first found a bent stud ball on the joystick connections under the boot. I thought maybe this was the only issue, it was not.The major issue was a threaded allen bolt at the far end of the boom spool had backed itself out. This bolt holds spring tension on the spool which keeps the spool in neutral when there is no joystick pressure. The bolt also gets pushed into a detent ball when the loader is put into the float position.I took some photos which will follow. Unfortunately this was all an after thought, the photos were taken after I fixed everything.The bent stud ball was under the boot here.

The loose bolt was under the left sided cap on the far end of the joystick here.

The loader works better than ever now!

May 9, 2014

I labeled all the lines.

Here it is re-installed.

You can see here how the stud balls fit into the joystick apparatus here.

May 9, 2014

Here is my rear grader blade from TSC. This blade paid for itself its first weekend.I only wish it had the horizontal slide out function which makes grading and cutting a ditch on a slope a little easier.

It feels good to have fixed this myself and have saved a bundle of money! dOdLooking forward to more seat time this weekend!

May 9, 2014

Here is the schematic of the valve. My big concern taking this valve apart was that the bearings and spring would go flying, and I would not be able to get it back together.

The bolt that had come loose from the end of the spool is in the box in the upper right of the page, 2nd image down in the box.It goes through the spring and threads into the spool, then a ball bearing fits over it and an outer cap holds it all together.

May 10, 2014

Nice write up, nice rig and nice job!

May 11, 2014

quote:Originally posted by Talntedmrgreen
Nice write up, nice rig and nice job!

id="quote">

id="quote">Josh thank you for the great feedback! :DI am glad you enjoyed the pictorial and write up. I figured someone may benefit from it, or find it of interest.This may have been a given easy fix for some of you vets around here, but I was pretty ecstatic I could fix this valve and save the cash, and not have my machine down.I thought there was a very good possibility I was going to have to replace it.Tomorrow I need to cancel the aftermarket I ordered which was supposed to take 7 weeks to get due to the horizontal mounting and loader action configuration.