Gradall 534D-10 0366439 I need to raise the boom on this machine. First, in order to get to the Cummins data plate on the timing cover, more importantly to work on/or replace the engine. I have used electric portable hydraulic pumps to raise booms on other telehandlers. A couple of sky traks, a jlg and even an ancient hyster Z90b. But all of those had hose connections that I could plumb into, iirc, gradalls are all hard lines from the control valves and the tees are part of the hard lines. Now that I am thinking about it, I am surprised that I have never had to figure out how to this before now. I probably have to deal with twice as many Gradall telehandlers than all other brands combined. And the way that the boom traps the engine cover when it is on the ground causes constant problems with any maintenance issue, so I was pretty surprised that a quick search didn't get me an answer. But since I am asking questions, I have a couple more. If I think of Gradall machines, I picture the two outer hoist cylinders and a center "slave" cylinder. I am not sure how they are plumbed together. I seem to remember that the slave is plumbed into the carriage tilt cylinder for load leveling but tilting the carriage doesn't effect the boom height. That question is not very important, I just wonder how all that works. The important part of that question is; what do I need to do with the slave cylinder in order to jack into the hoist cylinders to lift with an alternative hydraulic source? Can I just remove and cap the lines and let oil spill? Next question is less mechanical and more regulatory. Back in my operating days and my training people to operate back at the mines, it was drilled into my head (and I also drilled it into any trainees head) that when you shut down a machine, any implement absolutely had to be on the ground. 90% of the time when I see material handlers parked at dealerships or rental/sales yards they are parked with the booms in the air. I really want to tell any of my customers to let their freak flags and booms on material handlers, fly high. I just don't understand the rules.
Is the output line from the main pump a hardline also? I've plumbed into them in the past with a portable hydraulic supply pump to raise booms and buckets off the ground. On a 190 Dynahoe I purchased I removed a supply line to the hydraulic valve block plumbing in there and raised the front bucket clear to load onto a flat bed trailer. Can't answer for any regulatory things as I probably wouldn't comply anyway. I always leave the basket elevated if a system using counterbalance valves in the hydraulics. If they work correctly, nothing can come down.
Well I own a Gradall 534D6 we bought new in 1998 that we've repacked the main extend cylinder but that's about it other than hoses (knocks on wood). So looking forward to any intel if we need to do this procedure in the future. Can't agree more on the dealers yards with equipment implements raised sky high. They might know something more than I do but all hydraulic implements should be on the ground when the machine is shut down like you said MW. Went by our Kubota's brand spanking new building and all the new mini-ex's had their booms in the air. Don't think I have ever seen our local Cat, Deere, Kommie, Kobelco and Case dealers have any implements in the air on their lots. "Booms in the air" seem to be regulated to non-commercial dealers and some rental chains, at least in my area.
The big skylifts (125-135') manlifts take up way less room on the yard if you put the booms in the air. Plus potential customers may see them. Win win. The mast tilt/ slave cylinder isn't plumbed into the main lift cylinders at all. Its usually just on a pin at the base and a pin on the boom, as the boom goes up and down, it forces oil from one side of the slave to the mast/ fork tilt - to keep the forks level. You shouldn't have to mess with the slave at all to lift the boom. It will just tilt the mast as you go up. Is there any reason you can't get to both ends of the hard line and just remove it, and then put your hose on? to run your aux. pump? I would probably just use some other piece of equipment- forklift, crane, excavator etc. to lift the mast with the hoses off and let the oil run.
Can't answer regulations, but like 1693TA stated, telehandlers, hydrocranes, aerial manlifts all have holding valves on the boom hoist cylinders, they really can't come down. Think about it, would you climb in the basket of a 60, 80, 120 ft manlift and go in the air if there was a change it could "come down"? With that being the case, I wager a lot of rental yards raise the boom on their parked aerials simply because if makes them have a smaller footprint on there lot taking up space with those booms and platforms sticking out in the throughway of the yard. As for raising the boom on that dead Gradall, you'll have to pull the holding valves on the cylinders before it will move by lifting the boom with another machine. Don't have to worry about the leveling cylinder.
What about excavators, loaders, skids, etc?
Nope, although some such machines may have holding valves, it's not a given. But with aerials, cranes, manlifts, telehandlers, it's kind of automatic that those booms have to be designed that they don't/can't come down, otherwise bad things happen.
It was simpler than I thought. Of course the hoist cylinders had hose connections. One cylinder was plumbed jic 12 the other jic 10. So it was just getting hoses to connect the two with tees to run to the hoses I already had to lift the booms on the other machines I mentioned. And just used the porta power that runs my hollow jack. Bummer was, I was only lifting the boom to gain access to the data tag on the engine. And it wasn't even there.