Who Repairs Taylor Backhoe Joysticks

Here'southward a component that has been mentioned at various threads and folks have asked what kind of project is it to repair, the simple joystick control valve. From excavators to skidsteers, variations of this type pilot oil command valve are used on many machines nowdays, and the most common problem they have is leaking oil from the spool pistons at the top of the valve. It's typically just a tiny u-cup seal for the pistons causing the leak, replacing that seal is the challenge. I've repaired them within the cab with hoses still attached, and disconnected from the hoses every bit well. I prefer to disconnect from the hoses and cap or plug the hoses and so the valve components tin be tuckered of oil and cleaned. Likewise, much more comfy rebuilding while standing at a workbench than fighting one inside a cab.
My helper removed this one from a Example 9050B excavator because it was working all wacky, it was obvious someone had been inside this unit of measurement and had done something wrong. Later on he disassembled information technology, it became articulate to me the onetime shade tree wrench had not paid proper attention to what they had disassembled and had not performed right re-assembly, which I idea would do good others as to what I found inside the unit, and to circumspection anyone who attempts to take ane of these autonomously to note or marking the orientation of the valve mounting and every slice as to where it came from. I've repaired a couple of pilot valves, only I don't call up one being quite as specific inside as this 1. This may not be that unusual though, so note how you take ane apart.

This is a pic of the re-assembled unit of measurement, every bit I didn't have a picture of the unit when it was removed. Y'all can clamp the torso in a vise, put a wrench in the flats on the actuator deejay, and screw the universal joint out that holds the retainer plate on the top of valve assembly. I have seen the u-articulation installed with Loctite, making it all but impossible to remove it without destroying it, well, sacrificial role then, replace the u-joint.

Once you get the u-joint popped loose, work very carefully unscrewing it, those brass piston guides take springs underneath them, if you lot were to simply remove the u-joint and retainer plate, the resistance of the o-ring seal of the piston guides would allow go and parts would fly. Slowly screw the u-joint commodities out a bit, lift the retainer plate, and kickoff working the brass guides up out of the chambers until the o-band is unseated. Once they are unseated, concord down on the retainer plate and remove the u-joint, so y'all tin can gently elevator plate off of the guides. Hither'due south what you'll run across when you lot get the plate off and the piston guides out.

This is the spools and springs removed. The springs at top and bottom are the same, the spring to the correct is different, and and so is the one to the left.

Too, the jump retainer disks on the spools, 2 of them are thick, two of them are thinner. Fifty-fifty the springs on the spools held in place past the servant disks are different size.

Differences don't terminate there, the actuator pistons, the pigsty on the inside of them that the spool head fits into, ii of the pistons have a three/8" deep hole, the other two accept a 7/xvi" deep hole. Hey, ane/xvi" makes a difference in how a unit similar this operates.

So the delima is, what role is supposed to go where? Fortunately for me, the Case parts diagram was a cross section view with excellent particular, fifty-fifty the parts list page noted which part went in which port, such every bit the thin and thick leap retainer disks. If information technology had been an exploded view, probably been bad. The one thing I couldn't determine was the principal springs, the parts page told what spring went in what port by part number, but I had no way of knowing which leap was which part number, had to gild new springs just to get the function number of each spring.
Now that I take information technology sorted out how to assemble the unit proper, information technology's time to put information technology back together. Showtime though, nosotros demand to discuss the leak that is common with these units. Replace the o-rings on the outside of the contumely piston guides, and the seal that's in the bore of the piston guides. It's typically a small u-cup seal, or an o-band with a backup ring. Very simple to prepare a leaky valve once you lot get in there.

The claiming to put these things back together is the springs trying to force the piston guides back out, you have to hold them set in the valve body until you lot can fit the servant plate. It'southward nearly incommunicable to push all four spools/pistons into the unit using the retainer plate to strength downward as yous have to align each spool with the bore it fits into. You pretty much accept to fit each spool/piston unit in one at a fourth dimension and hold that unit in the valve torso. In that location are various methods to practise this, maybe some others hither will post some ideas, but this method has been adequately easy and effective for me. Clamp the valve trunk in a vise. I have some sparse/workable tie wire, twist a loop in one stop and fit information technology around the outside flange of brass piston guide. I used a 3/four" socket sitting on the face of the contumely piston guide to push the spool/guide assembly into the bore of the valve by hand. Once I push it home and hold it there, slack up the wire and tie information technology to fittings on lesser of valve. This keeps the spring from pushing the assembled unit of measurement back out. Make sure you have everything pulled taught, and accept a good tie off on the underside.

This is after all the units are installed and held in identify with wire.

Fit the retainer plate.

Then screw in the u-joint bolt, stop short of fully tightening it, exit room to nip the wires and pull them out with some pliers.

At present you can lock down the u-joint commodities. Check for proper contact of actuator plate on top of pistons, information technology can't be pushing any of the pistons down, nor practise you want a gap betwixt actuator plate and pistons. If aligning is needed, put your wrench on the flats on the actuator plate, and another wrench on the joystick lever nut on top acting as a jamb nut. Pop the nut loose, typically RH threads, then turn the actuator plate CW or CCW to obtain proper adjustment. Lock down meridian nut, you're done.
Great Pictures and text ATCO! It's tough repairing someone else'south repair. And it'south a sickening feeling when y'all realize to tardily that yous should have marked those pieces you just pulled out.
I have washed the same thing with ordering new springs that i mixed up or was unsure of due to another persons repair.
John C. Senior Member

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I take had the same problem with the springs and had no parts drawing to relate to. I figured the weakest jump went on exterior since that was the weakest mode to button the handle. The next was to the within and the heaviest springs were fore and aft.
Information technology seemed to piece of work the final time I did one. Also I've never had those things pop out on me. Normally I've had to apply plier and a rag to pull the spools from the bores.

Overnice job ATCO!
Atco, this forum wouldn't be the aforementioned without you lot!
Merry Christmas everyone
I thought the aforementioned matter most the springs John C. This was the left joystick, the strongest springs were fore and aft as you noted, stick extend/retract, which is the motion your arm has the most strength. Next lighter spring is swing right, which is a move your arm nevertheless has some force. The weakest spring, much weaker, was swing left, which motion your arm has the least strength. Seems there's some ergonomic design with these type configurations.
I've done this repair on the Hitatchi valves on 100'due south and 120's, same thing as you described, have to pluck the piston guides out, and setting them back isn't much of a job either. This valve...it had some SPRING to it, took a skillful bit of hold downwardly pressure level to hold the stiff springs while fitting the retainer wire.

Merry Christmas to y'all as well watglen.
Wouldn't exist the aforementioned? Bah ha ha haha
Hey, we got ourselves a "Store" department on the forum for Christmas, then I'thousand gonna mail some shop stuff here.
coalrulz Well-Known Member

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I have rebuilt airplane pilot controllers for deere and hitachi. I would ever order new Brass piston guides and piston (as an associates) and install. I agree with Atco, amend to remove pilot controller from machine then repair.
BLconst Well-Known Member

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Atco, I guess i broke the #1 rule and lost runway of which spring goes where. i accept 2 different types of spings for inside the plungers and ii dissimilar ones for outside the plungers.
Oh my BLconst, that doesn't expect good. Unless yous accept very proficient parts diagrams, information technology's difficult to decide exactly where the components go, and they accept to go in the correct orientation. What motorcar is it on? We'll do what we can to assist y'all re-assemble information technology, but information technology's difficult for united states on this stop.
One matter you can do, if all other plans fail, is to take the opposite side joystick off and very carefully accept it apart, probably needs seals anyway. The other joystick should be assembled in the same style, only the opposite right hand/left hand orientation.
BLconst Well-Known Member

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Its a cat 287b. bulldoze stick (left). See if this picture show clears it up. the large springs #six, i know where those become. My defoliation is the lilliputian ones. Give thanks you for whatsoever help. I can have apart the right hand stick, just volition it be the aforementioned since its a skid steer not an excavator?
Lee-online might be able to assist yous out with that i BLconst, he works at a True cat house.
BLconst Well-Known Fellow member

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Cat 287b left drive joystick.
trying to figure out if the tight spring goes with the loose spring or the loose with tight.
or the tight with tight

and which 1 is frontward/reverse and which pair is left right
What about the 4 big bore springs, are they all the same size?
BLconst Well-Known Fellow member

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Aye sir, the big spring #half-dozen are all the aforementioned.
Well, I'll take a wag at information technology, but keep in mind, information technology's only a best guess. The stiff springs pair up, and the weak springs pair up. The ii stiff spring sets become in the for and aft motility, the ii weak spring sets go in the left/right motility of joystick handle.
BLconst Well-Known Fellow member

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Thank you. Im gonna give it a try.
I don't supose one could disassemble the opposite side and see how that side is paired up? Not to boubt atco's wisdom and feel, just.. I believe in a dozer the lighter springs are fore and aft, and the stif are in the side to side motions to help keep you driving in a straight line.
You could be right stumpjumper, I really can't say one way or the other, just doing like yous and noodling through possibilities.
Consider this possibility though. When operating a dozer, you lot do brand turns and changes in directions. With skid loaders, you are typically making abiding turns and turnarounds. So it'south possible that it would exist oriented with the potent springs for and aft, the direction your arm has the near strength, and the weak springs left and correct, the direction your arm muscles are weaker to prevent arm fatigue from making constant turns.

Just a complete guess on my role.
BLconst Well-Known Member

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Well got 'er back together. Seemed to be okay. delay is gone only at present machine has a left side weakness, goes forward and dorsum fine, when i rotate total left or total right only the correct track is turning. i swithched springs and plungers effectually and did not make a difference. Maybe brawl resolver? possibly drive motor? I did notice that the ball resolver and the case for the plungers have updated, changed, part numbers. perchance fourth dimension to dump the 1300 on new joystick complete, such a shame later on a 500 sealkit!