Hydraulics won't hold

   / Hydraulics won't hold #31  
Yes, more than likely....
 
   / Hydraulics won't hold #32  
arcamm said:
Dummy question, my cylinders measure 2.5" OD. All of the specs I see are listed in ID. So would mine be 2" OD?
Click to expand...

That will change the intensified pressure to 4 times instead of 6.25...:laughing:
 
   / Hydraulics won't hold
  • Thread Starter
#33  
How is this for a valid test? Run the piston to one end of the cylinder. Disconnect the line on that end of the cylinder. Put pressure on the connected side and see if anything comes out of the disconnected side. If nothing comes out, the piston is sealing and the problem the valve. Valid, invalid, or will I blow myself up?
 
   / Hydraulics won't hold #34  
That is a good test. If nothing comes out of the open port, then you can assume that the cyl is good.

Put a bucket under the port if you can and catch the fluid coming out the cyl.

Did you try the needle valve. You should be able to lock the cyl in the up position. If the valve is closed, and the cyl is good, is should hold a long time. The weight of the machine will force fluid past the seals, if they are bad. .

I don't remember if you said anything about the relief, whether it was opening or not. If the cyl is good and the valve is good, and you keep the lever pull back all the way, the PRV should activate, and you can usually hear it.
 
   / Hydraulics won't hold
  • Thread Starter
#35  
I'm guessing the RV is working. I know when a ram gets to the end of the stroke, there is a slight pull on the engine, then the lag stops and the engine gets back to normal rpms. I ran a machine once that didn't have a PV, when you got to the end of the stroke and didn't let off, it would stall out the engine.
 
   / Hydraulics won't hold
  • Thread Starter
#36  
I've found out it uses Gresen V20 valve bodies and a 7 gpm Vickers pump. I'm waiting for the rain to let up so I can test it.
 
   / Hydraulics won't hold #37  
You could perhaps swap hoses from a known good cyl and test the outrigger cyl. Mark the hoses that you remove, and then mark the outrigger hoses. Install the assumed good valve and test the outrigger. If they hold firm, then you can assume that the valve is bad.
 
   / Hydraulics won't hold
  • Thread Starter
#38  
I got to run my test today. I retracted the outrigger then disconnected the hose going to the top (the extend side). I started the machine then pushed the lever to the retract direction (just a little, not all of the way). Fluid came out of the extend side hose.

According to my precise calculations, the fluid has to go past the piston packing to do that. Am I correct?
 
   / Hydraulics won't hold #39  
Yep, if the cyl doesn't move but oil's coming out then it's by-passing the piston seal......
 
   / Hydraulics won't hold #40  
Where did you remove the hose, at the cyl, or did you remove it at the valve? Did you hold the lever in the extended position in order to establish whether it was bypassing?
How long did you pressurize the base end of the cyl. Did you return the lever to neutral. What happened after that. A gage on the cyl would have indicated less pressure than the relief setting. I believe I had ask about the relief pressure.

What I gather from your statement is that you removed the hose at the rod end of the cyl, started the engine, and extended the out-rigger and held the lever in the extended position, and fluid flowed out the cyl port in a continuous flow for about five minutes.

And both cyl are doing the same thing?
 
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