main lift packing

[furltech]

Hi guys me again , completely perplexed this time i changed the packing in the main lift on my timberjack 230 and for some reason it is real slow now .i even changed back to the old packing to see if made any difference, none .i removed the spool it did not seem to make any difference took out the relief checked it. but i dont see any dirt in it the pump must be ok because everything else is working fine so i was thinking that a piece of dirt might have got somewhere i cant think of but it has me puzzled any ideas of things i might have overlooked .If it makes any difference it is a cranab boom

[snowstorm]

if you mean the blade. could be the other side is bad. they are hosed together

[Gary_C]

I just finished reworking my Cranab 650 XL loader main lift cylinder. But I had to replace more than just the packing. Seems if you lift the main boom clear up and drop the jib, the grapple can bang into the main lift cylinder and put dents in the barrel. It's been getting worse and worse so I finally broke down and replaced the barrel. It wasn't cheap but it sure goes faster and has more lift.

So if you can't find anything else, check on the inside bore for little dimples that have come from the dings on the outside of the cylinder.

That cylinder is supposed to have a guard on the side facing the bunk but on mine the guard was long gone. So I also bought a new one but have already broke it off and need to rework it. Seems the load gate has been pushed back far enough so as to rub on the cylinder as it swings. So I need to fix that too.

Just some ideas.

[John Woodworth]

How are the hoses from the valve to the cylinder? any kinks or could the hose have a restriction internaly?

[furltech]

How are the hoses from the valve to the cylinder? any kinks or could the hose have a restriction internaly?

Actually thought of this yesterday too ,did not seem to make any difference .it has to be dirt stuck somewhere in the valve bank i cant see what else it could be .

[Jamie_C]

Put the boom in a safe position (preferable straight out with the grapple hooked to the end of the bunk) and take out the spool for that valve section ... you might have a little piece of packing stuck in there somewhere ... as much as i hate to tell you to, when you have the spool out bump the key (but don't let the engine start) a few times so you basically flush out that valve section ... don't have anybody stand too close it can make a heck of a mess ... also if that section has the little "manual override" knob thingy on it then see how well the boom works when you use that ... it should look like the head of a 1/4" drive ratchet

[furltech]

good day jamie tried all of those things rebuilt valve bank.today did not find much of anything in it .i have the cylinder away to be bench tested to see if it is something i missed .oh well the poor weeks make the odd good one that much sweeter hahahaha

[Jamie_C]

where did you take it to get bench tested ?

it wouldn't be the first time the main lift cylinder had some improper repairs done to it or had the wrong size gland put on it and everything "looks" right but is off by a few thousandths of an inch and wont work

[furltech]

dropped it off at hawbolts this afternoon to have it checked to see if something was wrong with it .

[bushmechanic]

Are there reusables on the hydraulic lines?These can cause problems when not assembled properly and the inner piece will shave a piece of rubber off the inside of the hose then when using it it may block off the hydraulic flow.Did you reverse the hoses to see if that made any difference?Is it a Cranab 6025?I had to remove one once by myself and took out the bottom pin first and the darn thing dropped down and flattened out the 90 degree fittings and that slowed everthing down.Take a good look at the lines.

[furltech]

you know you might have something there .the lines have one reusable in them and we might have changed them around when we put the  cylinder back in place making the opposite line the pressure line .i think we had them on backwards the first time and changed them at the valve bank because it was easier .i blew through the lines with hydraulic but i guess if there was no real pressure you would never know .something to think about for sure .gotta say thanks for all the ideas everyone .

[kiko]

What is the pump up set that operates the crane?  A cyl packing that would create a slow would also cause the cly to leak down because of the oil going around the piston.  Sounds like a pump issue to me.  On the knuckle booms that I deal with the main boom cly always needs the most flow, and a pump slow death usally shows on the main boom cly.  Have any pressures been checked?

[furltech]

kiko got it after a super miserable day in the heat and the flies i finally stripped down the pump, to say it was past its prime is an understatement so new pump comes Monday afternoon .thanks for all your help