Leaking dump cylinder- DIY?

N80 · 2026-03-28T12:40:49-0400

I have a Kubota L4400. About 20 years old. Was moving some (too big) logs today and noticed a hydraulic leak on the bucket end of the dump cylinder. Not spewing out but steady drip when pressure on it.

I know nothing about hydraulics other than servicing car brakes. So several questions:

Is this a DIY job or should I take it somewhere?

Even if it is not a DIY job and I need to take it somewhere is removing the cylinder a DIY job.........and if so, is putting it back on a DIY job?

To remove it it just looks like you remove the two hydraulic hoses. The loader is off the tractor now so can I assume there is no dangerous pressure in the cylinder? The pins have a nut and bolt through them to hold them in place. Are the pins hard to remove? More importantly, are they hard to get back in?

Thanks for any advice.

TMGT · 2026-03-28T13:03:46-0400

If you are mechanically inclined at all it's a fairly simple process to remove and even repack those cylinders. A large adjustable will remove the gland nut(or a pipe wrench if you dont mind chewing up the gland from the jaws).

I can't remember the nut size for the piston, but its not overly large, if you have a regular 1/2 impact set you should be good.

You can replace the seals carefully with picks and a small screwdriver, but the seals tools are pretty cheap off Amazon.

Most likely you'll be repacking the other cylinde in short order.

Sent from my SM-S921U using TractorByNet mobile app

AntiqueIron · 2026-03-28T13:37:55-0400

N80 said:
I have a Kubota L4400. About 20 years old. Was moving some (too big) logs today and noticed a hydraulic leak on the bucket end of the dump cylinder. Not spewing out but steady drip when pressure on it.

I know nothing about hydraulics other than servicing car brakes. So several questions:

Is this a DIY job or should I take it somewhere?

Even if it is not a DIY job and I need to take it somewhere is removing the cylinder a DIY job.........and if so, is putting it back on a DIY job?

To remove it it just looks like you remove the two hydraulic hoses. The loader is off the tractor now so can I assume there is no dangerous pressure in the cylinder? The pins have a nut and bolt through them to hold them in place. Are the pins hard to remove? More importantly, are they hard to get back in?

Thanks for any advice.

It’s not a hard job. They aren’t light but they’re not hard to take on and off. Just make sure you support everything for safety.

Word of caution- anytime somebody asks me if they can do something themselves, that to me says that at the least they should study some educational materials to learn more about the subject.

Yes you can do it, but if you’re unsure and have never done this type of work before, I’d have somebody walk you through it.

N80 · 2026-03-28T14:05:40-0400

Thanks guys. I'd say I'm moderately mechanically inclined. I've removed the bevel gear assembly from this tractor to have it serviced. I've taken the bed off my F150, removed the fuel tank and replaced fuel pump. Stuff like that. I've got decent tools but no special skills or experience either.

I can watch some videos and my B-I-L farmer just down the road has a pretty big tractor shop and he can walk me through it and/or bail me out if I screw it up.

But now I am wondering if it is fairly simple it might also not be too expensive to have someone else do it?

DJ54 · 2026-03-29T07:58:05-0400

I'd advise leaving the cylinder on the loader, only unpinning the ram end. Slightly block it up near the end of the barrel to remove the gland nut. Maybe even mount it back on the tractor to make it more stable.

Once the ram and piston are removed, you can replace the seals in a vise. If you can find a parts manual for the loader, whether hardcopy, or online find the OEM part number(s) for the seal kit, use those numbers to do a Google search to find the correct seals.

Piston will need to be removed to install internal gland nut seal, and require a good bit of torque when re-installing, like somewhere between 450 ft. lbs. to 750 ft lbs. Clean bolt and internal threads and put thread locker on the threads, I used Loc-Tite orange on mine. You may be able to find torque specs by using Google unless you have access to a service repair manual for the loader. A decent impact gun should torque it to specs.

Might check with your B-I-L and see if he has any internal seal tools to replace the inner seal in the gland nut. If not, I'd highly recommend getting a set. Fairly inexpensive, I bought mine from Amazon, they sure make installing the internal seal a lot easier. I've posted a pic. below for reference.

I had one rebuilt at a hydraulic shop 15 years or so ago. Kit and rebuild was right at $100, with a 90 day warranty. I'm sure it's more now, but just to give you an idea what it may cost.

N80 · 2026-03-29T08:18:40-0400

My B-I-L came by our place yesterday and I asked him about the cylinder. He said it was easy to do but not that expensive to have someone else do and he is taking a couple of cylinders to his 'guy' and he said he'd take mine over there so I'm going to let him. Of course he didn't say how much so I might be surprised. His work gets paid for on the farm budget. Mine gets paid for on the 'hobby' budget.