Hydraulics won't hold

arcamm · Apr 6, 2011

Here are some more. The last picture, looking from the bucket side bact to the operator, the left lever is the right outrigger, the 6th lever from the left is the left outrigger and the 7th (farthest to the right) is the rear outrigger.

J_J · Apr 6, 2011

Unless you test things, and provide feed back, is is difficult to analyze the situation. For instance, If you can test the cyl, and verify whether good or bad that will lead you to the next possibility. You can eliminate the cyl by doing the needle valve test. Use a needle valve or gate high pressure valve, and install in the A port/base end. Connect the outrigger cyl hose to the needle valve. Start the engine, and raise the machine up on the outriggers, and close down the needle valve. If the unit stays up, then you can assume that the cyl is good.

Is there any auto leveling system installed for the outriggers? .

arcamm · Apr 6, 2011

J_J said:
Unless you test things, and provide feed back, is is difficult to analyze the situation. For instance, If you can test the cyl, and verify whether good or bad that will lead you to the next possibility. You can eliminate the cyl by doing the needle valve test. Use a needle valve or gate high pressure valve, and install in the A port/base end. Connect the outrigger cyl hose to the needle valve. Start the engine, and raise the machine up on the outriggers, and close down the needle valve. If the unit stays up, then you can assume that the cyl is good.

Is there any auto leveling system installed for the outriggers? .

No auto leveling that I'm aware of.

Any idea of what model/series the valves are? I know they are Gresen/parker, but that's about it.

I'm looking for a high pressure valve.

J_J · Apr 6, 2011

You mean a new valve for your BH?

J_J · Apr 6, 2011

Try here

Hydraulic Cylinder Components, Products

220-951

arcamm · Apr 6, 2011

J_J said:
You mean a new valve for your BH?

No, a needle valve and a high pressure gage so I can trouble shot this thing.

J_J · Apr 6, 2011

If I were you and did not have the parts and time, I would take it by a hyd shop and have them test that valve and cyl. They would have all the test components, such as valves, gages, fittings, etc.

I am not saying that you can not do it, but you will need a minimum of shutoff valve, gage, fittings, etc. Labor around here is about $60 to $95 per hour. They should be able to test your system within two hours. It depends on how soon you need this machine back in operation, or get it ready to sell. The good people on here can guide you to a successful fix.

arcamm · Apr 6, 2011

It could come to that, but right now, I'd like to get as far as I can myself. I don't have a lot of pratical experience with working on hydraulics, but I've always been a hands on learner. Right now, I just want to get this machine to work. Later, I'll restore it.

wdchyd · Apr 6, 2011

arcamm said:
Right now, I just want to get this machine to work. Later, I'll restore it.

Good Thinking.....:thumbsup:

arcamm · Apr 7, 2011

Dummy question, my cylinders measure 2.5" OD. All of the specs I see are listed in ID. So would mine be 2" OD?

wdchyd · Apr 7, 2011

Yes, more than likely....

AKKAMAAN · Apr 7, 2011

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?

That will change the intensified pressure to 4 times instead of 6.25...:laughing:

arcamm · Apr 7, 2011

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?

J_J · Apr 7, 2011

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.

arcamm · Apr 7, 2011

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.

arcamm · Apr 8, 2011

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.

J_J · Apr 8, 2011

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.

arcamm · Apr 10, 2011

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?

wdchyd · Apr 10, 2011

Yep, if the cyl doesn't move but oil's coming out then it's by-passing the piston seal......

J_J · Apr 10, 2011

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?