Hydrolics questions

insanity

insanity

Joined
Feb 28, 2002
Messages
392
I need to fix a hydrolic press at work (needs to be fixed for work, but I want to fix it so I can use it for forging). It has two sets of cylinders that run independintly from each other off the same pump. One set works fine, the other set barely moves at all. I think that this eliminates the pump as the source of the problem. The two areas that I think are the most likely problem areas would then be either the hoses (don't leak, but are old and have a bunch of connectors on them) of the cylinders. Any thoughts on this would be appreciated. Is there a way to further diagnose the problem without complete disasembly and testing each individual component? Or does anyone have any thermite so I can slag this POS and have an excuse to build a new one?

WS
 
The first question that comes to mind for me is whether or not the machine is losing any fluid.
 
One of the cylinders of the set that is not working has a very small leak. Overall there is enough oil.
 
Loss of fluid is a loss of pressure. Maybe that set is under enough load thay they won't work with a small leak? The pump probably doesn't move a very large volume of fluid, so any loss is hard to overcome.

I agree with IG (scary thought :p ). Try switching the lines and seeing what happens also.
 
You said that the sets run independently from each other which tells me there is valve to switch which set is operated.Could be a likely cause, also do you know if there are any flow controls in line, another spot to check.If possible do what IG said and swap lines.Could also be the cylinder seals starting to leak by.Dave
 
Wayne, The first thing to check is the flow control valve for the non-working cylinder.If may be bad ,or set wrong.George has a good idea in switching the hoses to see if the problem changes cylinders.Also look for a shut off or by-pass valve in the line,it could be closed.One more thing is to make sure that the cylinder and the track for the ram,are not rusted shut or jammed.
Stacy
 
Thank you everyone for the help, especially with my spelling. I started taking the hoses off this morning to try switching them around when I notice something sticking out of the end of one of them. I think to myself, self that isn't right. I pull it out and it is a three inch piece of a ring seal. What do you know everything work great now, at least till one of the very old and decrepit hoses bursts. I think the seal got into a line when a cylinder blew out 8 or 9 months ago (before I was useing this equipment). Oh well, thanks again.

WS
 
Wayne,one more thing - Replace those hoses!!! you don't want high pressure hydraulic fluid spraying all over the place,especially if it might hit red hot metal!!!
Stacy
 
Please becareful switching lines around. You can easily blow some component up. With by pass hang-up or failure most of our pumps can generate several thousand pounds or better. A piece of cast iron from a small or large pump that explodes at 4000 psi can kill you just as quick. I recommend that you understand how your system works. Diagram your system. A high pressure leak can produce a concentrated jet of oil at 2000 psi that will cut you like a water jet and potentially kill you. Get an oxygen guage and plumb it in line to different hoses to diagnose problem. If this unit has two sets of controls it needs to be converted to one set. Rubber can flake off the inside of old hoses and cause intermitant problems. You might have to replumb your system in parallel with equal lentgh supply and return hoses, and discard check valves and divider valves.

I'm not in hydaulic service or engineering, I' a farmer. I've been through several experts. I paid for my education one repair problem at a time for 30 years. I don't want to see anybody get ripped off or injured...Take Care...Ed
 
The hoses are next on my list of thing to bug my boss about till he replaces them. If he is real stuborn about this it will be time for the icepick fix. The up side to getting put in charge of maintaining all this crap is that I am gaining a lot of experience quickly so when I build my own press I might actually have a clue. Thanks again.

WS
 
Note to Ed Schempp - Don't use an oxygen guage to chech hydraulic pressure.If you reuse that guage on an oxygen line you could create an explosive situation.They lable all oxygen guages "DO NOT USE OIL" for a very good reason- pressurized oxygen/oil mix is quite explosive.
Stacy
 
Totally correct about reuse. My O2 guage is permanantly stored with my hydraulic fittings. I suggest an O2 guage because it is about the cheapest readily available high pressure guage. Thank for bringing that important safety issue forward...Take Care...Ed
 
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