I've a 1994 gmc 3500 with bucket truck when it's engaged and using boomed out or booming in pto disengages

Hi,

those buttons should be on the front of the boom box. But if you can't find them, please check the back of the boom box.

Otherwise, you'll need to use page 24 of the manual to help identify the buttons.

Thank you.

all booms have manual
and page called emergency lowing valves
for safety.

the class covered this in training on all brands I used.
never lose the manual or get stuck, you will

on most/many
ay the bottom near hyd.pumps are bypass valves.
the manuals most the last pages has 800 number for emrg. stuck help,. << bingo ?
download the manual from them if lost.
do not mess with the jacks if boom is up.
the class covers that to.

call em
and do not listen to cat or dozer guys, telling you
dangerous acts that end with oil on the ground
only ask ,maker even use a Phone
they will ask you TERRAIN questions and slops etc, first.

https://versalifteast.americommerce.com/manuals.html

Is there an interlock on the boom that wont allow it to operate if the front blade is not set? There could be an issue with hydraulic fluid, pump or PTO.

ive heard of folks doing it without a crane but i would not try it , alignment is too critical with getting guides and stops back in and with nothing to move boom that would be too difficult

anyways: suspend boom end with double straps from crane , disconnect hydraulic/electric swivels/plugs at truck end lift end of boom slightly with boom all the way extended straight out , remove acess panel (both sides) at jct of upper/lower boom section . remove C clip one side drive out pin oppisite side (wiggle boom to clear pin) locate stops in lower section boom end unbolt , slowly pull upper boom with crane away take care of hydraulic lines and electric wires set on floor on wood cribbing , locate bottom of cylinder truck end find C clip and pin Might be behind a trim cover that might need to be remove drive out pin also remove bottom cylinder hyd hose connect crane to cylinder end move out a foot or so remove top cyliinder hydraulic hose then carefully slide out cylinider with crane , Note if your valves are not tight and new oil will leak back and cause boom base to sag when you unhook hydraulic hoses , your gonna need to block this up with wood cribbing just in case

reverse removal process to install new one , also i would not just install a new seal (you can) with out having cylinder recromed I'll bet it's rusty thats what tears the seals up
and allways replace entire oil volume in hydraulics your old seal is in old oil not good for the new one

Is the machine leaking any fluid?

Sounds like you are talking about a Ford F450 diesel truck. Try posting this in the Cars and Truck section or give the local Ford dealer a call. This particular forum is for pump problems, not what a manufacturer includes on their vehicles. Good luck.

You most likely have a defective hydraulic control valve, I would start the testing there.

You can purchase an adapter from any electronic parts supply.
The specifications are:
AC/DC Adapter - Output:15VDC 4A Positive tip.
You can find these specifications in the bottom of the boom bucket.

your spool valve needs rebuilt

Try Walter Miller auto literature its an ebay USA store they may have what you need you could also try International or the bucket body manufacturer for this