Auxiliary pressure relief for mini-excavator.

[440chevy]

I've been looking for something to go onto my 50u Hitachi for about 6 months now so that hooking attachments up isn't such a pain. Seems like whenever we use our helical pier auger, we have to crack the lines to get the thumb hooked back up. Or sometimes to even hook up an attachment in the first place. Anybody know of anything good that we could retrofit onto it?

 

[landtekk]

When you change attachments , shut the machine off, turn the key back to the on position and cycle your aux controls. and that should relieve any pressure in the lines. Scott

 

[440chevy]

When you change attachments , shut the machine off, turn the key back to the on position and cycle your aux controls. and that should relieve any pressure in the lines. Scott

I've tried it, along with everything else me and the dealer could think of. Nothing we do to the machine seems to work.

 

[Orchard Ex]

you can buy quick connectors that hook up under pressure.

 

[440chevy]

I use the high pressure couplers that are standard on bobcats and what not. Same as the ones pictured.

 

[Hendrik]

Don't really know but hook up a pressure gauge to the line and then try and relieve pressure, maybe there is a one way safety valve in the system?
Does the operator manual tell ya anything?

 

[John C.]

You also have to open the cap on the hydraulic tank before cycling the controls. Otherwise you will still have about 15 PSI on the system.

 

[willie59]

You also have to open the cap on the hydraulic tank before cycling the controls. Otherwise you will still have about 15 PSI on the system.

Hey John C, I'm not sure about this so I thought I throw this question your way, maybe you could answer; Could it be he can't release the pressure on the aux circuit because he has a pilot operated foot pedal and there's no pressure to operate it with the engine not running? I'm no expert on aux circuits and I'm curious about this.

 

[John C.]

It's possible but there is supposed to be an accumulator for the pilot circuit that would allow the lowering to the ground of any raised equipment should the engine suddenly die.

I have seen many of those accumulators loose their charge though. To test, just raise the boom all the way up, shut down the engine and then try to lower the boom.

 

[willie59]

It's possible but there is supposed to be an accumulator for the pilot circuit that would allow the lowering to the ground of any raised equipment should the engine suddenly die.

I have seen many of those accumulators loose their charge though. To test, just raise the boom all the way up, shut down the engine and then try to lower the boom.

Interesting. So if his system had the accumlator; he would shut off the engine, then turn the key back to ignition, have the safety lever in the "operate position" (since this controls the pilot circuit oil), then he could rock the aux pedal back and forth, and this should relieve the pressure on the aux circuit to allow coupling disconnect. Is that pretty much it?

 

[440chevy]

You also have to open the cap on the hydraulic tank before cycling the controls. Otherwise you will still have about 15 PSI on the system.

That's the first thing the dealer suggested that I hadn't done. Crack the tank. I'm really surprised no one else has this issue. The hydraulic shop around here says it's a pretty common problem- doesn't matter the brand.

 

[440chevy]

I was thinking of just putting a Tee in the line and a valve just so I don't have to crack the lines and have them leak every time. Don't know what else to do.

 

[John C.]

If all that doesn't relieve the pressure you will have to go with the ball type quick connects that pop open when you screw the sleeve tight.

 

[Orchard Ex]

I use the high pressure couplers that are standard on bobcats and what not. Same as the ones pictured.

I use the ones with the black ring that allow you to hook up under (some) pressure. They are compatible with all the other flat face connectors like your picture but they cost a little more.

It's possible but there is supposed to be an accumulator for the pilot circuit that would allow the lowering to the ground of any raised equipment should the engine suddenly die.

I have seen many of those accumulators loose their charge though. To test, just raise the boom all the way up, shut down the engine and then try to lower the boom.

I think John C. is onto something here. Try the accumulator :thumbsup

 

[440chevy]

Well, if you shut the engine down turn the key back on and move the controls nothing happens. I've never been able to lower the boom on any john deere excavator we've owned with the engine shut down. I would hope there is a way, but I've sat in that machine listening to the radio on screwing around with the controls (with the safety lever on) many times.

 

[Cal]

You could install a schraeder valve of sorts to the top of your oil tank and push it to release the air each time ? Kinda like the Case machines have