For a week now working on this crane hyudraulic system.Booms up nice,normal.Booming down very,very slow.Hyd.pump labors harder which I can here.Service done:replaced old rotten hyd.oil filters,repacked both hyd.cylinder,r&cleaned pressure relieve valve,r&cleaned up boom down boom control spool.All clean.Also when left up I can here pop here and there as boom comes down slowly on its own.There is no visible hyd.oil leaks on hoses,fittings.I belive the repacking of main cylinders was wrong recomendation,everything was done not long ago which I found evidence of but I did it anyway.I was hired to do it.Now what next?What am I missing.Also one of the main cylinder has some over load control unit with pilot line.Cleaned that too.No dirt,instaled new O-rings,however have no idea how to preset the pilot line adjustment,rather where is the zero or neutral setting if this is the correct term.Also would like to learn the proper way to do hyd.system diagnostic-trouble shoot problems.Thanks to all who will help me.
I know absolutely nothing about this machine, but pretty much any hydro crane will have some form of holding valve on the boom hoist and telescope cylinders that will prevent the boom from coming down or scoping in the case of a hose failure. That pilot hose could be some form of load device, but it could also be an external pilot line to release the holding valve to boom down. Without any knowledge of the machine and its components, it sounds like the holding valve is not being popped open to allow boom to come down by the controls. It also sounds like the holding valve has some internal leakage if the boom is drifting down. Could you post some pics of the connections to the boom hoist cylinders?
Thank you sir,holding valve-makes more sence-even more from safety point of view.However without manual-service book I have no idea where this valve is located.I hope it is not in the acumulator unit which is hiden in the centre of the crane tower.I took pictures of the control unit on one of the cylinders and now I have to learn how to get it in to my computer and send it out.When I was 15 I knew everything,now at 60 I feel I know nothing,never mind forty years of hands on.
Where the heck are my manners, I should have said welcome to HEF. :drinkup Check out this link and see if it matches your machine. > ftp://38.106.177.129/gopettibone/forms/dealersold/crane/25-29-30-36-40 mkp parts book.pdf
Hi again,is this forum site on timer?I sent reply to your last mail and I was disallowed.
If you're logged in, and sit idle for a spell, it will automatically log you out, have to log back in to make a post.
OK,anyway I went through all of the 169 pages of that link.I will try to ID the controls from the pictures.It is quite a job to look throgh the snake pit of hyd.hoses,never mind the spools bolted to the floor from underneath.Thanks again for your help.By the way what is HEF stand for.Happy Ending Friend?One more,where would I find the reply message that was disallowed?
H.E.F. = Heavy Equipment Forums I don't know that you can recover the disallowed message. I think everyone here has been snagged by that at one time or another, after a while you learn to make sure you're logged in, like I said, it's happened to all of us. Does that parts manual look like your machine?
Sounds like a holding valve issue. They are always located on the cylinder. They are supposed to hold the cyl. in event of hose failure. It actually takes quite a bit of pressure booming down to open them. As far as testing them and setting them its tough to do in the field as there are not usually ports on the cylinder to hook into and specs are hard to find. Every time I thought the valve was an issue I put in a new valve cartridge the was preset, cheaper than pulling the cylinder apart. Most of the time it corrected the problem. If not the cyl. packing was the next suspect. There are a lot of valve cartridges on modern hydraulics that are tough to set in the field.
I printed off all I could.Run out of ink twice.Thanks again,I will let you know next week how things went
All day on this machine,printed off all I like and will do the ID tomorrow.My first reply to your last one didn't go to your address but to another member's one.Learn,learn until we know .
The boom hoist cylinder cross section only shows a port at the base of the cylinder, this would indicate that some form of manifold attaches to the bottom cylinder port, that manifold would likely have the holding valve in it. The upper circuit diagram shows the boom hoist cylinder retract circuit (yellow). Item #8 shows to be a "JIC 90 deg elbow (modified)", meaning, it probably has a thread hole in it for item #16 elbow to "tee" into it. #16 elbow is connected to what looks like an external pilot circuit (red) that goes to the manifold at base of cylinder to unlock the holding valves for the cylinders. SPECIAL WARNING: If it does have holding valves fitted into the manifolds at base of boom hoist cylinders, DO NOT attempt to remove those valves unless the both boom hoist cylinders are fully retracted. Even then, be very careful and slowly remove them as there may be residual pressure against those valves.
hi again.put everything back together,fired up,same problem.Goes up nice at idle speed ,will not go down regular speed ,pump works hard.On the down stroke of this lift cylinder am I to have hyd,oil pushing down on cyl.head-gland?If so I have no oil in hoses at all.(yellow line on schematic)The hose comes out of large cylinder sitting in the midle of the tower and is fed from underneath straight from the pump.Also I took pictures of holding valve,accumulator?I trasfered it to my lap top but have no idea how to post pictures on this forum.If I had email address I send it right from my phone.Also I took the holding valve apart once again found more short tubes with small and larger holes in them however I am not sure if anything missing.Others tryed to fix this problem and don't remember if anything came out with some sticky hyd. oil.Present oil is darker but clean.Will try something again tomorrow.
Again I ask, does that parts manual look like it's for your machine? The Multi-Krane spanned many years and was made in a dog house cab version and a swing cab version.
I know you're still trying to figure out this forum thingy, I'm going to send you a private message with my email address, send me the pics and I'll see what I can do with them. Go to the very top of this page and look for the Notifications link. Click on Notifications and you'll see a private message from me that you can respond to.
Ok, I received the pics you sent, I must say that boom hoist cylinder you have looks nothing like the one in the parts manual (posted above in post #12). Likewise, the manifold at the base of the cylinder looks nothing like the one in the parts diagrams. Not sure what's up with all this, maybe every part in the manual doesn't match your machine, maybe someone put some different cylinders on the machine in the past, and I'm not saying it's never done, but I myself have never seen a crane boom hoist cylinder that has a welded pipe socket in the base with a pipe nipple to connect the holding valve manifold to the base of the cylinder. If something whacked that manifold and broke that nipple that boom is gonna come down faster than you can say dammit! And the other pic that you thought might be an accumulator is actually the center swivel. It's a nine port swivel to deliver oil from the lower frame control valves to the various crane functions of the upper. 4 ports for the two telescope cylinders, 2 ports for boom hoist, and 2 ports for the winch, the 9th port is most likely connected to the tank lines of the lower for the case drain of the winch motor. I can't see all the port connections in the pic, all I can see is what is in the top plate, which would likely be the 9th port (tank). I'm curious of what that small hose with the adjustable needle valve is connected to.
Found a Photo of a Pettibone MK 25 with a good view of the lift cylinder . Second photo down on the left . Looks just like the diagram in post # 12 . Check valve manifold looks to be bolted securely to the base of the cylinder . All the boom & outrigger check valve manifolds I've been around are either bolted to the cylinder or welded . http://www.recoveryseeker.com/WH/WHDetails.aspx?ItemID=24002
You're right TD, the boom hoist cylinders in the link you posted are like the ones in the manual. There's something very different about this unit, may work the same in plumbing, but very different. A couple of more pics from P.F.Z. > Another view of left boom hoist cylinder holding valve. Hose connections to hoist cylinders. Additional view of swivel.
I must admit I've never seen such a mess of hoses, tees, and valves to do something as simple as operate boom hoist cylinders. I don't see any way possible for me to figure out what's doing what, especially with the internal porting of the manifolds, unless there was some form of schematic to work with, and that might be difficult to find. I might be able to at least get close if I could tell exactly which hose was going where on both the manifolds and the swivel. Regardless, to make this simple, there should be only two connections to the swivel, one for the boom cylinder extend, and one for retract. There may be a possibility of a third connection to tank line to drain internal pressure inside the holding valves to prevent differential pressure, but that's a maybe. Aside from that, two lines, one for cylinder extend, one for cylinder retract. Obviously we'll have to tee off these lines because we're working two cylinders with just one common port, i.e., one port on swivel goes to cylinder extend on one cylinder, then we have to tee off that line to extend the other cylinder, same for cylinder retract function. The other thing we have to do is unlock the holding valves to make the cylinders retract. To do this we tee into the cylinder retract line and send it to a certain port on both manifolds. When you apply pressure to this certain port, it unlocks the holding valves and allows oil out of the bottom of the cylinders while retract oil pressure is forcing the cylinder in at the top of the cylinders. That's my best guess of how that thing should work. But there's no way I can say what port is what on those manifolds.
This is about as simple as I can draw how I think that system should work.
Also, I can't explain why there's 2 cartridge valves (holding valves?) in the left cylinder manifold. Are there any cartridge valves in the right cylinder manifold?
Hi there,not having much luck sending more emails or reply's to your email address.All keeps coming back-mail delivery subsystem permanently fail to deliver.Anyway thanks for the last picks.Project is on hold.Sharp crane inspector wouldn't pass it most likely.Thanks again for all your help.Mean time I battle with Kubota tractor and Clark C-500 fork lift.All "good deals" and my nightmares.
Hmm, I can't imagine what the problem would be as that's my work email and I receive email daily. :beatsme
Hello, do you can send this manual agais?