Need basic bleeding air knowledge from double acting cylinder on lift truck. Wont lift n there are no bleeder valves....please help
We will need a little more basic information about what is going on in order to contribute anything meaningful. What exactly are we working on? What are the symptoms? When did the problem start? Why do you think it needs to be bled?
It should bleed itself on a double acting cylinder............but double acting cylinders are not the norm for lift cylinders on a forklift to begin with.
Dealer tech here to help I've been turning wrenches for 13 years now. I've worked at a CAT, Bobcat and curently a Kubota dealer. I'm currently advanced certified by Kubota in mini excavators, CTL's and Skid Steers. I also am factory certified in New Holland construction and AG equipment. Just trying to help people... HeavyEquipmentForums And... Hello all...hoping i learn much here! Have issues with a Jungheinrich 110 b push around lift. I posted but not sure in the right place. Fairly inclined but this one stumps me. HeavyEquipmentForums
Might not be air in the system. Piston seal leaking ?
Thank you all for replies... this is a 2009 Jungheinrich HC 110B push around forklift. Cant find much in internet other than pics. I bought used and had it at half way point no load and it just started to go slowly down. I regret not realizing it was low in fluid so i topped off hoping I did not get air in system. To me that would be the most likely scenario but cant be sure. I tried again to try and lift but no go. I did not want to run the pump and possibly cause some other damage. the 2 lines from pump go to the bottom and top of cylinder with no bleeder ports. Is there a procedure that i can follow? this lift has a big wide base.
Great, picture helps a lot. That may be a common machine marketed under different names. In any case, I'm guessing the guts are very similar without going out in the cold to look or get more pictures. The second hose possibly uses the upper part of the cylinder as a fluid reservoir as cost savings. Almost certainly does not have down pressure! There should be no need to bleed the cylinder, but the pump will not pump air against pressure, it must get the air out of the pump itself before it will develop pressure or suction. Part of the problem may be that the pump is activated by the valve control handle so that the pump can't turn on and run without being "blocked" by the control valve. In other words, it can't operate in open center mode, because the valve control also turns on the pump. Try to hold the handle so that the pump operates without moving the hydrualic valve, if that fails, then operate the pump electric switch inside without the hydraulic control handle. If that fails, you'll have to open an outlet hose and let the air out that way. It won't hurt the pump to run with some air, there will be enough oil to run for thirty seconds at a time, since it was functioning properly, it's not dry in there.
Ty but I am confused... here is a pic of the pump . Not sure what that black box in front is. Maybe this will.help. the machine does have a up n a down button . Not sure if the pump ran when down button was pushed. I thought that if cylinder.had a top n bottom port then it would be a double ...ty
ty for response... wasnt sure if all could see post. Please follow and any advice.
I've never seen a box like that, but it looks like a solenoid to operate the hydraulic valve, and that sure looks like a hand bleeder screw on it. Try loosening either the aluminum or brass parts and see? So you have only buttons for the controls, no hydraulic valve handle, so ignore what I said about the handle. If that lower black box solenoid operates on "up" then disconnect the wires and try it for ten seconds at a time until the noise changes. If that solenoid operated in "down" then I'm not sure how to precede. Do those two hoses go to the two ends of the cylinder? are there any other parts that could be an electric solenoid hydraulic valve? The one thing that doesn't make much sense is the part about "half way point no load and it just started to go slowly down", if the pump sucked air, I'd think it should stay there and just stop lifting. Did it have a large load when it started going down?
Was a while back when the problem occurred. I might have had 150 lbs on it just not sure. But she did just go down slowly on her own. Those hoses go directly to the top n bottom of cylinder with no other solenoids or valves. 1st pick is at the bottom of cylinder and you can see other hose goes to the top...2nd pic. 3rd pic is at the back of reservoir. Not sure what that red knob in the back does. Wife has a video of it operating.
The previous pic showing the lower port on bottom of cylinder n the top hose being connected to the metal pipe with that hose clamp tells me that the top line has no real hydraulic pressure so it's really not a double acting cylinder?
Yes, the top hose could be a vent, or to return any leaking oil to the tank. It is NOT a double acting cylinder the way it's hooked up, it's a double acting cylinder with one side not used for pressure.
Also never noticed any fluid leak anywhere on unit
Lots of good info today. The battery is toast so no powering up. I took pics of that solenoid black box with the brass n silver fittings. The brass one turns open and there are 2 tiny holes on it (pics). The brownish wire on that solenoid goes up to the button switch for down forks. I noticed that where that solenoid is connected to frame of pump housing is near the port for the pressure side (hose going to bottom of cylinder) seems this solenoid is energized when down button is pushed which does what to the pressure channel? Closes it? Guessing here. Makes much more sense in a way. So I imagine the next move might be to pwr her up and open that brass fitting while using the up button. Not sure if the solenoid is normally closed or open. Thinking its opening a channel when energized allowing the fluid back into the reservoir as the weight downward pushes the fluid out of cylinder ? Maybe I am way off here.
It looks like a simple lift hydraulic system to me. You have an electric/hydraulic power unit with electrical solenoid activation. The electric motor will come on and force fluid to the bottom of the cylinder for up. The down switch does not require the motor to activate......it uses an electrical signal from the down button to open the solenoid to lower the forks. That hose at the top is for leakage/venting. The should also be a lowering bypass valve, maybe manual, that can be opened to drop the forks in case they are up and the system faults.
The lift truck thingy is cool, but I’m more interested in learning about the tombstone biz, Mr.Tombstoneman. How about a proper introduction? What’s the strangest words you have engraved on a stone?
Ty for response... nicely explained but still need help. The down button solenoid opens a valve?. That solenoid is pictured with the brass fitting. So how do I go about getting the lift to work? Thks
Dabbing in it for sure. Just a small biz owner now that worked for large companies for 35 years.
There is a red knob near the filling cap on reservoir... would that be the lowering bypass valve? But since ithe forks are in the down position now does that matter? Appreciate the help. Should I see if the down solenoid its clicking and is that a bleeder valve on the down solenoid? What are my next troubleshooting step.
Nothing bad yet...I had way more crazy things to put on those big chocolate chip cookie pies when I was a teenager working for cookie company...lol
Since I can't see how the system is plumbed, I'm going to say the red knob is the emergency lowering valve. Make sure it is completely closed. You can simply unplug one of the solenoids and work your up and down switch and see which function is not working to determine which is up and down.
yes, my guess is the solenoid controls a normally closed valve, which opens to lower the forks. The motor runs and only lifts, that is, it lifts anytime the motor is turning and oil is pumped. Did you run it with the brass bleeder open? cover it with a rag and don't get your fingers near there, run it a bit and if oil spits out, then stop and close it. How slowly did the forks settle when it stopped working? and had they held solid before the problem? like you could leave it for hours before and it would only drop an inch, but now it drops an inch a minute or what? If the cylinder is settling down, then it's either leaking back through the valve body, or through the cylinder seals and through the low pressure return/vent hose. If the settling was slower than the normal raise, then I'd expect it to still raise with a leaking cylinder, so there's no clear answer here.
ok will try and pwr her up and use the bleeder. What i remember was a steady slow but all the way down. it was solid before this happened with no issues at all. Guess i will try and see today...ty for all your help
I pwrd her up and opened the brass bleeder and nothing came out. no oil .... I used the up button for about 10 second bursts about 4x. closed bleeder and tried again... no lift. I felt the solenoid click when i pressed the down botton and verified that i have 13v when activating down. I could feel the pressure hose while lifting button and it feels like fluid is running thru there. Looks like I could have issues with cylinder seals? Is there anything else to try? Thanks
You could be feeling the motor vibration through the hose, very hard to tell. If you take the low pressure vent hose off at the top, and it's has oil in it after running, then I'd say the cylinder piston seals are leaking. That's pretty unlikely though. The more likely issue is the lower valve somehow failed internally, that might be as easy as a torn o ring, or it might be very hard to spot.
I loosened the fitting on top of cylinder n ran the lift...never saw a drop of oil leaking out. When you say the lower valve what do you mean? Ty
The valve will be the part under the black box solenoid that activates with the down button.
Will turning the silver wheel under brass fitting remove the solenoid and valve?
I couldn't say. Guessing the silver wheel will allow you to remove the black plastic coil only, and the valve fastening will be clear once the coil is removed. There could be a relief valve in the vicinity also that could cause this issue.
Did you see the pic of the red plug near the reservoir cap. A member said that could be a manually emergency down by twisting it open. I cant see how a plastic part like that could even work. I will try n post it for you again.
Yes, I'd agree. Vetech has much more experience than I do. I've never seen a forklift with a manual lowering valve, but then I've never seen an electric controlled forklift, or one built to CE standards. See if that turns counterclockwise, or if there's directions or any labels nearby.
I pulled that red knob off and there is a fitting as in pic. That down solenoid black plastic piece has play in it (the black box twists a little back n forth).
That picture of under the red knob doesn't look familiar to me. Closest would be an adjustable relief valve, but it could be a manual lower valve, I just can't say. The black plastic coil will be a little loose, it contains the electric coil that operates the magnetic plunger inside the core, so the coil is replaceable without opening up the oily parts. You'll have to open the oily parts to look for valve issues, after removing the black plastic coil.