Kubota L3710 Steering Seal Fix?

[Suburban Plowboy]

I have some unfortunate corrections to make to the post I made about getting the steering cylinder out.

I thought there was only one bolt holding the front end of the rod in place, and that bolt is exposed when you remove the battery tray. Sadly, there is a second bolt behind it, and Kubota puts it on good and tight. You won't be able to get a box wrench on it very well, and if you use one, you will probably round the head.

These two bolts keep a piece of sheet steel ("rod end shaft stopper") in place, and the edge of that piece goes into a groove around a pin ("rod end shaft") that holds the hydraulic rod in the tractor's frame. The piece of sheet prevents the pin from coming out. To get the rod loose, you have to take the bolts out and move the plate. Then the rod end shaft lifts out easily.

To get to the rear bolt, I drilled a 7/8" hole over it, in the grey part that blocks it. This part is something like 1/8" plate, and it's part of a frame structure that supports various things. The area I drilled through is way overbuilt, so drilling a hole in it will not cause any problems at all. I used a punch to locate the hole. Then I made a tiny pilot hole. Then I opened it up with a step bit. After that, I finished with two Silver & Deming bits. I deburred it with the step bit. I used plenty of oil. Once I had the hole drilled, I was able to put a socket on the second bolt ("rod end shaft stopper mounting screw") and pop it loose with a breaker bar.

Only one bolt appears in the manual, so the second one was a lovely surprise.

My cylinder has two fittings, and one has an S-shaped steel line that runs under the cylinder, putting the hose connections next to each other under the tractor. It is not easy getting wrenches on the connectors. A 19mm or 3/4" crow's foot wrench will help. Obviously, you need two wrenches on the connector to the steel line, because you can't apply torque to a thin pipe. You need to have one wrench on the line's fitting and one wrench on the hose's fitting

The two bolts on the Pitman arm cap are on tight from the factory, and it's hard to get a wrench on them, so expect to fiddle around coming up with a socket combination that works.

Once the hoses are off, the rod end shaft is out, and the Pitman arm cap is off, you will have to lift the cylinder out of the hole its bottom boss rotates in. You will probably have to retract the cylinder manually in order to get it out. There is a big washer that will fall out, so look out for that.

I think drilling the hole in the frame on the front of the radiator is a good idea. It can't hurt anything, and it takes a ton of work out of the job. Kubota should have done it.

 

[2manyrocks]

If you could please, a picture or two would help the rest of us understand what you just explained.

 

[Suburban Plowboy]

I would love to do that, but I don't know how much I can do. Everything is black in there, and the parts are already out. Maybe I can do something once the tractor is going back together.

 

[Suburban Plowboy]

Here are a couple of quick shots that might help.

One shows the hole I drilled. I measured 1" back from the edge of the plate to center the hole, and it seems to have worked. Under the grey plate, you can see the structure that holds the steering rod end at the front left corner of the tractor, which is in the lower right-hand part of the photo. In this photo, the pin that holds the rod in the frame is out. You can see the little plate that holds the pin in, and the two screws that came out of it are sitting on the part I drilled.

The other photo shows the cylinder, including the hard line which is attached to it. I did not see this line in the manual or any parts photos, but I may be mistaken. Anyway, it would be a big mistake to try to remove the hard line from on top of the cylinder.

 

[2manyrocks]

Thank you. Very helpful to understanding how difficult this is.

 

[Suburban Plowboy]

The cylinder is in the hands of a hydraulic shop. They are thinking the rebuild could be in the area of $250, which amazed me, since it's just new seals and O-rings. I have emailed them to make sure they understand I don't want to use genuine Kubota parts unless there is a good reason to. If I manage to get cheaper parts, I will list them here for other people.

Kubota charges $17 for a 60mm circlip, which is 95 cents on Ebay.

 

[BeezFun]

Be interesting to know the breakdown of labor and parts. I would guess a small cylinder like that is an hour labor, which is probably $100ish. Hard to imagine non OEM seals being more than $25. I've never had a little cylinder like that apart, I wonder if there's something that makes them harder to work on.

 

[Suburban Plowboy]

It ought to pop right open. Both ends are held on with snap rings.

 

[Suburban Plowboy]

I got my cylinder back. The cost of rebuilding it was about $220.

The bill says I paid $20 for freight, although I carried it in myself. I paid a $10 environmental fee, for a cylinder which contained no oil that had to be disposed of. Shop supplies, unspecified, $15. Labor $90, which means one hour. Add it up, and it looks like I paid $135 for things other than parts.

I don't understand the freight charge, and I don't think this cylinder took anything like an hour to fix. They said there was nothing wrong with it other than old seals.

So other people can rebuild their own cylinders, I will list the parts installed. They add up to nearly $90.

MUU-25X33X5 U-seal 2 @ 13.63
MSWE-25X33X5 wiper 2 @ 4.25
MOR-49.5x3 O-rings 2 @ 1.13
MPS-55X4.3x2 piston seal 1 @ 36.15

The U-seal must be from Hercules, because their MSRP is $13.63. From Hercules, the seal is $10.23. The wiper is $3.19 from Hercules. The O-rings are 85 cents. The piston seal is $27.11 from Hercules. So I lost a few bucks paying MSRP, but on the other hand, no shipping cost.

If I had known all this now, I would have bought Kubota seals and repaired the cylinder myself. I would have paid for shipping, but I would have saved something like $80. If the cylinder poops out again, I'll just buy aftermarket seals.

I don't know why seals for this thing cost so much more than seals for other Kubota cylinders. I thought Kubota was just trying to stick it to me, but this is clearly not the reason. I mean, yes, they were trying to stick it to me, but I thought the seals should be around $40, like kits for other Kubota cylinders, and it turned out the piston seal was so expensive, there was no way Kubota could sell me all the things I needed for under around $90. They wanted about $130, which is unreasonable, but a $40 ripoff is better than the $90 ripoff I thought they were trying to pull off.

This cylinder is also used on a bunch of other Kubotas, so the information posted above will work for them as well.

I have 4 more Kubota cylinders, and kits are available for all of them, so this should be the last time I ever have to pay for a rebuild. Kits for my cylinders list for $50 each, so I should be able to do all of them for a little more than $200.

At least I can say this failure occurred right at the time when I needed to replace my hydraulic oil and filters.

Hope this info helps other owners.

 

[2manyrocks]

FWIW, I recall paying about $200 for a hydraulic steering cylinder rebuild on my Mahindra in 2020 or 2021 from one of the better rated hydraulics shops in my area. All they did to mine was to replace the seals.