Lull boom cylinder removal safely? Holding valves?

[davedj1]

I hope someone can offer some advice. I am going to be the new owner of an older LULL 644 telehandler. The main boom cylinder (inside the boom) is leaking at the rod end. I'm trying to get my ducks in a row for when I get it delivered as what to expect to pull it. I have been researching and found there may be some load holding valves that could possibly have residual pressure in them. I guess my question is will these valves have to come off or can I replace the seals with them still attached?
Any advice or help greatly appreciated.
Thanks,
Dave

 

[4570Man]

Does it have double cylinders on the side of the boom or a single under the boom? How bad does it leak?

 

[Groo]

if you unpin the cylinder and move it a bit in both directions, that should eliminate any trapped pressure

 

[davedj1]

Does it have double cylinders on the side of the boom or a single under the boom? How bad does it leak?

I'm not talking about the lift cylinder, this one is inside the boom and is what's used to extend and retract the boom. It's about 10' long and looks to be about a 2" bore. It's leaking enough that it needs to be repaired.
I'm working on getting a picture of the machine.

 

[oldnslo]

On most telehandlers the load holding safety valves are either built in or hard plumbed to the cylinder. This is required so that if a hose fails the load does not move. Depending on the valve style you may have to remove them to rebuild the cylinder.

 

[davedj1]

I had a fellow on a heavy eq. site send me the service manual online so I'm stoked about that. I probably won't get the machine for a week or so, logistics of it all.

 

[davedj1]

Well I ordered the cylinder rebuild kit and it should be here any day now.

 

[davedj1]

Well got home from the hospital (Our daughter had our second grandson ) and the seal package was sitting on the front porch so hopefully sunday it will get installed.

 

[davedj1]

I had the Lull delivered to my house today so I can tear it apart. I have already had my first two snags, 1) the hose for the fork tilt cylinder is too short to drop the cylinder down out of the way to get to the large nut on the end of the shaft which is problem 2) I don't have a socket large enough to fit it! I have up to 2 1/8 and it's not big enough, I have to go shopping for some larger stuff tomorrow.

Problem 1) solved, I unhooked the hose and took the hose off my top link cylinder which has a quick connect on it and just screwed them together.
Problem 2) I'll report back at a later time

 

[davedj1]

Reporting back
Problem 2 solved, bought a 2 1/4" socket and an 18" extension. I had to put a 5' pipe on my 3/4" drive ratchet and a pipewrench on the rod, I broke it free
A friend who used to work on equipment came over to help me, we got the cylinder out and rebuilt and back in and running in 5 hrs. Not bad. The cylinder is 14'-8" long
Other than being a greasy mess it wasn't all that bad, thankfully I had my Kubota with the new forks on it standing by fr duty.
Here's a picture of it going back in