Lull 644 inner boom cylinder disassembly tips

[jfdube]

Hi everyone
Does someone have tips/advices/method to take the inner boom cylinder out from (Lull 644)?
This is a pretty long and heavy cylinder and I ask you guys for good tips to avoid more damage!!

Right now involved hoses are disconnected, reel line removed, cylinder pin removed...
I placed the boom on horizontal position secured with a post located under outer boom section, machine parked, wheels secured.
The cylinder is actually in the position it had when the problem occured. Extended to (C) section.
Problem = no retracting action + massive hydraulic fluid leak.
Cause = steel pipe break on top back end of the big, long cylinder.
Medecine = Take the cylinder out for damaged pipe welding.

Is it possible to retract this (damaged) cylinder in place with a hydraulic jack, chain block, strong straps or other way?
I tried today with small ''clic, clic'' straps and the cylinder didn't move at all.

Ok I guess you have enough info about my problem!!!

Can you help me?

Thanks
J-F

 

[willie59]

I've never removed the boom telescope cylinder on a Lull 644, can't help much there, but I can guarantee that cylinder has holding valves on it preventing you from "jacking" the cylinder in. Most likely cartridge type valves at base of cylinder. You could remove these holding valves and then possible retract the cylinder with some form of jacking, but it's gonna make a mess with oil coming out of the hole that the cartridge valve was removed from.

 

[jfdube]

Thanks

I don't mind for oil mess!!!
J-F

 

[willie59]

BTW, which series of 644 do you have?

 

[jfdube]

I don't really know!

Here the infos I got about it
year 1989
Model 644-TT34 highlander II
Closed driver cockpit for our cold winters!

J-F

 

[willie59]

Would you happen to have the S/N handy?

 

[jfdube]

I don't know about S/N?
Excuse my lack of knowledge!!
What S/N mean?

J-F

 

[willie59]

No worries, Serial Number.

 

[jfdube]

Not on hand tonight.

You look for something specific?

J-F

 

[willie59]

No and yes, its just your thread removing the lift cylinder may be helpful to others, or it may yield good info for you from others, one never knows. The 644 is a long running model number, a number of variations. Even in the Highlander series, there was a number of changes, S/N might be needed for more specific info.

 

[jfdube]

Ok I'll check on info plates in the machine.
I'll check tomorrow morning if it got some more specific answers.
I'll let you know the rest of the story.

See ya
J-F

 

[willie59]

If it's a 1989 the S/N should look something like this (X inserted wherever it could be several choices of number or letter)

X9UXXX-XXX

 

[joestewart]

I'm making preparations to pull out the boom extend cylinder on my early '90s Lull 644. Haven't done it yet so can't offer any tips, but I can email you the service manual! - gives step by step on how to remove said cylinder!

Those "cartidge type valves" might have a lot of residual hydraulic pressure underneath them, so be careful when loosening them (safety glasses and keep hands/fingers out of the potential trajectory - those valves could shoot off of there like a rocket) - Given you had a huge hydraulic leak, most of residual pressure has probably been dissipated though. PM me your email address and I'll send the manual over the wire.