Rebuilding a Kubota Loader Boom Cylinder

When it rains it pours here. Before I could work on the boat top I had to fix my tractor. It's drying up around here and Debby is pulling a cold front all the way down here. With lots of trees still on the ground I've got to get back on cleaning up.

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So first things first I unload the weight of the loader by moving the hydraulic control valve around. Then 2 bolts retaining the cylinder pins & the hydraulic lines were removed. I tie the lines up so oil doesn't leak out then using a 24in Pipe Wrench break the Gland Nut loose while the cylinder is still pinned to the frame. Once the gland nut is loose I slide the pins out, remove the cylinder, and bring it to the welding table. Once inside I clean the outside of the cylinder very well, blow it off with air, then check the Rod real well for any damage.

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The best place I have found to secure a hydraulic rod to break the Piston retaining nut is on the equipment it was attached to. Here with a 30in breaker bar I'm removing the retaining nut. Still very hard to break loose. Red Loctite on the threads.

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The piston still didn't want to release so I put the nylon hammer on it. I bought this hammer in 1977 from Tony's Auto Parts in Westwego, La. It is a lifesaver for this kind of application. Oh, it's Cal-Van tools brand hammer.

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https://www.youtube.com/watch?v=CmGjG--JSp8&t=895s

I have OEM Kubota Seals, at $205 a set you want to get it right the first time. The center picture is a must have tool for installing the Rod Seal inside the Gland Nut. Since I could not film and install I referenced the video I watched a Hydraulic Shop Guy install them. I was happy to see he had the same seal installer tool set as I have. All the seals and o-rings were installed in the Gland Nut then it was set aside.

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After I removed the piston seals I placed the new seal on top first then added the Kubota hydraulic oil all over then used the heat gun to patiently warm the new seal then used my thumbs to push it in place. I didn't have to use a tool to install it.

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After oiling the cylinder rod and sliding the gland nut on I washed the threads with contact cleaner, blew them dry, then applied the Red Thread Locker and torqued the nut while the rod was pinned onto the tractor. After the nut is torqued I wet everything down with hydraulic oil, slid the rod into the cylinder vertically and carefully. Tightened the gland nut till I couldn't hold it inside on the table anymore then reversed the balance of the removal steps to complete the repair.