Nicholas Fluhart

September 21, 2009

Hydraulic Repairs

Filed under: Project: AC Forklift,Trucks & Equipment — Nicholas Fluhart @ 7:45 pm

Time for some repairs! Since I’ve owned this forklift it’s had minor leaks in the primary lift cylinder and one of the tilt cylinders. The secondary lift cylinder and the other tilt cylinder were still in good shape. Eventually, the lift cylinder leak developed into a steady drip leaving puddles wherever it was operated and one day the tilt cylinder oil seal blew out altogether. It was time to address the issue.

I had my company mechanic helping me on this job; it’s nice to have a hand on the heavier stuff. Many people are afraid to work on hydraulics, but cylinder repair is actually fairly easy. In fact, most of it is easier than working on motorcycle forks.

I started with the lift cylinder. Given its size, it was easier to disassemble on the machine. We unhooked the lift chains and lines accordingly. We then used a chain wrench to remove the gland nut.

Removing the Gland Nut

Removing the Gland Nut

Once the gland nut was removed we were able to begin pulling the ram tube.

Removing the Ram

Removing the Ram

Inspecting the Bore

Inspecting the Bore

Once everything is loose, the ram pulls right out and you are ready to install your new packing components. The wiper seal is typically located in the gland nut and the guide bands are usually on the ram.

For the tilt cylinder, we simply removed the whole unit and disassembled it on the bench. It comes apart the same way as the lift cylinder. Once we had the parts pulled we were able to measure for replacement packing.

Removed Laid Out

The lift cylinders are single acting. They power up and load gravity pulls them down. The tilt cylinders are double acting, they power in either direction.

Rather than search for parts online, which is what I usually do and probably what I should have done here, I figured it would be faster to go to the local hydraulic shop although they are typically very expensive. It turns out, the seal used on the lift cylinder was obsolete (or so they told me) and hard to order, so the shop fitted the gland nut with a more common seal diameter by using a lathe to turn the inside of the nut to a larger diameter. The other components were easy to order but unfortunately, the entire process took them about two or three weeks because they apparently had systematic memory failure which inhibited them from placing the order for the seals in a timely fashion. The cost of the parts and labor from the local hydraulic shop (not including hydraulic fluid and the labor on my end) was $198.00. Once I got all my components we had the machine back together within a couple of hours and it was ready to go. I think next time I’ll find the parts myself…cheaper and faster.

Click Here for an UPDATE.

Click Here for more hydraulic repairs.


  1. I don’t know If I said it already but …I’m so glad I found this site…Keep up the good work I read a lot of blogs on a daily basis and for the most part, people lack substance but, I just wanted to make a quick comment to say GREAT blog. Thanks, 🙂

    A definite great read..Jim Bean

    Comment by JimmyBean — October 1, 2009 @ 5:29 pm | Reply

    • Thanks for the comment. I hope to have time to add content regularly. I have a lot of projects going and hope to finish at least a few big ones over the winter. I guess it just depends on my work schedule…….too bad I have to spend all my time making a living. LOL

      Comment by nfluhart — October 14, 2009 @ 1:25 am | Reply

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