Reconnect Hydraulic Line to Backhoe

Yuhong · Apr 20, 2019

I made a stupid mistake and am seeking advice.

Tractor: Kubota L3301, Backhoe: Kubota BH77. Almost new, only 23 hours.

I disconnected the backhoe to hook up the disc. While disconnecting the backhoe, I DID NOT RELEASE the pressure in the Hydraulic Line in backhoe. After using the disc, I tried to hook up the backhoe and the hydraulic line would not be able to be connected. After some discussion, we realized that there was some pressure trapped in the hydraulic line preventing the lines to be connected.

Right now the backhoe is still sitting on the ground. What would be the best and easiest method to release the pressure in the backhoe's hydraulic line? Then I can reconnect the backhoe to the tractor.

Thank you all very much.

Digou (408-688-4299 - cell)

RNeumann · Apr 20, 2019

In general BH have the controls with the implement so it isn’t attached to the machine. If that’s the case you will need to brace the BH (so it doesn’t fall over or something) and run the valves in all directions to relieve the pressure. If the machine doesn’t have a valve to the BH QDs you will also need to make sure the machine is off so the machine side QDs don’t have pressure. If the machine does have a valve, turn the machine off and cycle the valve to relieve pressure.

If I’m thinking about this wrong then you will need to push in on the middle of the male QD. This can be easier said than done without the little tool. But with some thinking you can get it done without the tool.
Dave's Delights Hydraulic Hose Pressure Relief - YouTube

Dave M7040 · Apr 20, 2019

Yuhong said:
I made a stupid mistake and am seeking advice.

Tractor: Kubota L3301, Backhoe: Kubota BH77. Almost new, only 23 hours.

I disconnected the backhoe to hook up the disc. While disconnecting the backhoe, I DID NOT RELEASE the pressure in the Hydraulic Line in backhoe. After using the disc, I tried to hook up the backhoe and the hydraulic line would not be able to be connected. After some discussion, we realized that there was some pressure trapped in the hydraulic line preventing the lines to be connected.

Right now the backhoe is still sitting on the ground. What would be the best and easiest method to release the pressure in the backhoe's hydraulic line? Then I can reconnect the backhoe to the tractor.

Thank you all very much.

Digou (408-688-4299 - cell)

You can also start to unscrew the hose from the coupler until it starts to leak and then just let it leak for a little while. It does not take much fluid to be released to drop the pressure as the hydraulic oil is in-compressible unlike air.

However, the backhoe either needs to be collapsed as much as it physically can or supported so you are not waiting for a cylinder(s) to reach the end of their strokes..
A block of wood and a heavy hammer. Strike the exposed ball with the wood protecting the ball. Fluid will be released. May take a few strikes.

Remember, the fuid being released is under high pressure so eye protection and gloves.

Dave M7040

ericm979 · Apr 20, 2019

Most likely the problem is not that you didn't relieve pressure in it before disconnecting, it's the backhoe settling on it's cylinders. I've had that happen. I block it up when I take it off so that the backhoe is not putting weight on the dipper or outriggers and the bucket's on the ground.

You can release pressure on the male connector end by gently striking the tip with something. If it's a nipple instead of a ball at the tip (as is common with OEM couplers these days) I'd recommend unscrewing the connector from the hose. If it's the female connector on the backhoe that won't allow you to connect you have to unscrew it. Yea you could stick a screwdriver in there and hit it with a hammer but that seems too likely to damage something. The pressure in the hoses will be a few hundred psi not thousands like when it's operating.

When I take the backhoe off I connect its connectors together. It keeps them clean and out of the way and with both sides connected it's less likely to develop pressure (but it can still happen).

Yuhong · Apr 20, 2019

That should be it: "Most likely the problem is not that you didn't relieve pressure in it before disconnecting, it's the backhoe settling on it's cylinders. " When I stationed it. The backhoe arm was not in its mots collapsed stage. I will try to support the entire backhoe so the backhoe is not settling on it's cylinders. This may make the backhoe not putting weight on the dipper or outriggers. So, the pressure will be released. Then I will try to connect them again.
Meantime, I will do some research on Kubota BH 77 to see if I can do this: "If the machine does have a valve, turn the machine off and cycle the valve to relieve pressure. "

All these are very sound advise. What would be the best for me to do if I need to disconnect the backhoe again (Which I will do often)? I only have one tractor and I need it to work on disc harrow, plow, box scraper, and other implements, plus the backhoe. Maybe it is time to ask wife for another tractor? Better not.

Thank you all so much.

Digou

PS. I will try to post pictures if I did it successfully. (can we pos picture here?)

Fallon · Apr 20, 2019

For any impliment...
Put supporting material under it if needed and/or set it on level ground.

Put the machine in park.

Turn the machine off.

Work all the valves so there is no pressure on any cylinders or on the machine.

Disconnect the hoses & unhitch the impliment.

If you do that when the fluid is cold & later hitch up on a warm day, you can still have issues due to the fluid heating up & expanding. But the above steps will give you the best chances to avoid issues.

RNeumann · Apr 20, 2019

Yuhong said:
That should be it: "Most likely the problem is not that you didn't relieve pressure in it before disconnecting, it's the backhoe settling on it's cylinders. " When I stationed it. The backhoe arm was not in its mots collapsed stage. I will try to support the entire backhoe so the backhoe is not settling on it's cylinders. This may make the backhoe not putting weight on the dipper or outriggers. So, the pressure will be released. Then I will try to connect them again.
Meantime, I will do some research on Kubota BH 77 to see if I can do this: "If the machine does have a valve, turn the machine off and cycle the valve to relieve pressure. "

All these are very sound advise. What would be the best for me to do if I need to disconnect the backhoe again (Which I will do often)? I only have one tractor and I need it to work on disc harrow, plow, box scraper, and other implements, plus the backhoe. Maybe it is time to ask wife for another tractor? Better not.

Thank you all so much.

Digou

PS. I will try to post pictures if I did it successfully. (can we pos picture here?)

Out riggers down, bucket on the ground and thumb against the bucket. Then turn the machine off and run all the levers until their is no more movement of anything on the BH. Then unplug the hydraulics to the BH.

Dfixit1 · Apr 20, 2019

RNeumann said:
In general BH have the controls with the implement so it isn稚 attached to the machine. If that痴 the case you will need to brace the BH (so it doesn稚 fall over or something) and run the valves in all directions to relieve the pressure. If the machine doesn稚 have a valve to the BH QDs you will also need to make sure the machine is off so the machine side QDs don稚 have pressure. If the machine does have a valve, turn the machine off and cycle the valve to relieve pressure.

If I知 thinking about this wrong then you will need to push in on the middle of the male QD. This can be easier said than done without the little tool. But with some thinking you can get it done without the tool.
Dave's Delights Hydraulic Hose Pressure Relief - YouTube

Thanks for the link! Today was so nice I got the utv and went for a spin and visited a neighbor one mile away and he had just removed his front snowblower and subframe on his fairly new Kubota 35 hp cab and was trying to install the loader and couldnt push them on. I determined the tractor side had no pressure but the loader side did. We tried to push the center pin with no avail. I suggested loosening two fittings on the loader frame. When he loosened I was able to install the lines.
I had a similar experience with my backhoe.
Time to make two of these tools!
Thanks to Dave on YouTube too!

bdhsfz6 · Apr 26, 2019

I connect a home made manifold to the hoses of my backhoe and other hydraulic implements when not in use.

Any pressure buildup is easily eliminated by opening the valve. The expelled oil is easy to collect without making a mess.

CincyFlyer · Apr 26, 2019

As others have mentioned, just whack the [covered with a cloth] ball on the QR fitting to relieve the pressure. I actually made a little device out of a gear puller that grabs the outside of the fitting and easily presses the ball (or whatever kind of valve it has.) I often change stuff on my tractor, front and rear, and the only time I don't need to bleed is if I remove something in the heat of the day and reinstall it when it's cool.

Yuhong · Apr 26, 2019

Thank you all for the valuable input. Just an update, in one cool morning (a few days after the initial disconnecting the backhoe), I was going to try to jack up the backhoe so the dipper arm would not be pressed back. Before I did that, I tried to connect the male and female together on the back hoe. They were connected. Wow, I immediately backed my tractor to the backhoe and I was able to make the two connection. I was speechless. I had no idea what had happened and they just went in. I wiggled the tractor and made the proper aliment for the hooks and pins. So the backhoe was back on the tractor. I am not planning to take it off until I am done digging holes. Thank you all again. Next time, I will make sure I do each step properly, so I will not have the same problem again. Right now, Central Coast California is drying up. I will need to move a bit quicker before it is bone dry. Tips and advises, please email me. digoupang@gmail.com. Yuhong

kthompson · Apr 26, 2019

In post 9 the tee and an adapter look to me like normal pipe fittings. If they are, not rated for the pressure of a hyd system.

Fallon · Apr 27, 2019

kthompson said:
In post 9 the tee and an adapter look to me like normal pipe fittings. If they are, not rated for the pressure of a hyd system.

True, but the manifold is designed to hold the QDs when the lines are depressurized & keep them that way. So there should be little to no pressure on those plumbing fittings.

Yuhong · May 4, 2019

Another update， hydraulic hose from backhoe to tractor was somehow cut. It was rubbing without the sheath (the one only has 1/2 covered with sheath.). Anyway, I went online and found the factory parts with one dealer in East Coast (Parts #10 for Kubota Backhoe 77, <$25.00). I went to local Kubota dealer and got one made, cost about twice as the factory part (hose + two ends, hose was charged by foot, about 20, the two ends together just cost a bit over 20.). It was opposite of what I thought. I thought the factory parts always would cost more. But it is not true for tractor? Anyone who has experiences, please share your feels. Thank you.

ericm979 · May 4, 2019

Factory parts often cost less than custom parts. They make the factory parts in batches so they have economies of scale. Making a part one at a time costs more.

Also the two Kubota dealers local to the 408 are not cheap. I've had hydraulic lines custom made from hydraulic shops in the 408 and they're more like $30 for a couple feet of 3/8 hose with ends

RNeumann · May 4, 2019

Local dealer is charging what he/she wants with “little” competition. You obviously pay for convenience too.....heck you payed double to have it “now”.

Vs the online dealer has to compete with hundreds of other folks selling the same thing- and its only a click away.

Reconnect Hydraulic Line to Backhoe

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