Backhoe Power Beyond for Backhoe

[dfkrug]

I took a picture of the backhoe valve. In the one picture the red circle is around a rusted six sided nut...maybe. It is on the SWING section for the valve bank. Is that a relief valve? It the only one that is rusted like that and I broke the loader valve exactly when I swung the boom to the right and now the pump broke when I swung the boom to the left. This could be coincidental but I have been thinking about that for a while now and today I took the covers off the backhoe and see this. The other picture is of the end section that I think the main relief of on.

That looks like a shock relief valve. These are often seen on the boom,
dipper, and swing circuits. For the swing ckt, you should have one on
the other side of the valve, too. I see you have a swing speed control
valve, too. That's the cross handle on the front of the swing spool.

 

[jgbanshee]

I just learned that my Bradco did not have a main relief valve in the end section of the valve. I was told by Bradco that the relief was an option for that backhoe. Mine just has a plug in it. I ordered the main relief today. Now with the backhoe relief and the loader relief I hope to be in business.

 

[john_bud]

I just learned that my Bradco did not have a main relief valve in the end section of the valve. I was told by Bradco that the relief was an option for that backhoe. Mine just has a plug in it. I ordered the main relief today. Now with the backhoe relief and the loader relief I hope to be in business.

Ouch!!!!

That would have been a useful bit of information to know -- before you added that flow diverter.


Well, expensive lesson. Honestly, I'm not sure I would have done a physical check on the hoe having a relief valve. Probably wouldn't have - and been like you - a lot poorer.

On the bright side, you now know a fair amount about hydraulics!

jb

 

[KJM]

Ouch!!!!

That would have been a useful bit of information to know -- before you added that flow diverter.


Well, expensive lesson. Honestly, I'm not sure I would have done a physical check on the hoe having a relief valve. Probably wouldn't have - and been like you - a lot poorer.

On the bright side, you now know a fair amount about hydraulics!

jb

Ditto me. I can't quite see why anyone would have this as an "option"!? Relief valves are there so as to keep the pressure within range for the equipment. This seems a bit crazy to have the valve optional - it implies that the pumping system is lower in pressure than the implement and that there is some kind of flow-bypass in the pump. Which there probably isn't... So with this hoe, when you hit something solid and curl the bucket, the pressure will basically just keep going up until something breaks, because the pump is now effectively dead-headed. Just seems utterly crazy, design wise.

Is there something (else) I don't understand about hydraulics, or is this basically right?

/Kevin

 

[jgbanshee]

Well the backhoe came off of a New Holland LS??? skid steer. When I spoke with the tech at Bradco I gave them my serial number and they told me the backhoe was the newer version of the 11HD. I am guessing that the backhoe was to be run off of something that already had a power beyond valve in the system.

 

[john_bud]

Yep, I agree with that. The original application must have had a system relief they were counting on. It seems pretty spooky to set a system up like that, but...it sounds like that's what skid steer people do.

jb

 

[jgbanshee]

I replaced the plug in the end section of the backhoe with the main relief I got from Bradco today. I also got my new Cross loader valve in the mail too today. This valve has Power Beyond. I am assuming that as long as I connect the hyd lines correctly, which I think they are, everything will work fine. Any comments?

 

[john_bud]

"comments"

Check, check and double check that the routing is like the diagram I attached a while ago. If you do that, it will be a wonderful thing.

jb

 

[dfkrug]

Ditto me. I can't quite see why anyone would have this as an "option"!? Relief valves are there so as to keep the pressure within range for the equipment. This seems a bit crazy to have the valve optional - it implies that the pumping system is lower in pressure than the implement and that there is some kind of flow-bypass in the pump. Which there probably isn't... So with this hoe, when you hit something solid and curl the bucket, the pressure will basically just keep going up until something breaks, because the pump is now effectively dead-headed. Just seems utterly crazy, design wise.

Is there something (else) I don't understand about hydraulics, or is this basically right?

No main relief on the backhoe's valve stack?

I can think of two possible explanations:

> the hoe may have a relief for every work port. On my hoe, they are
called "anti-shock" relief valves. If all the work ports had them then
your hoe would be protected.

> Bradco makes sturdy hoes for the skid-steer and other commericial
markets. They sell hoes targeted to applications that are known
to use the tractor's or SS's hyd system, which have system relief valves.
PTO pump systems (which usually have no relief valves) would be
where Bradco adds their optional hoe relief valve.

 

[jgbanshee]

Well I got the Cross valve with PB installed completely today. New pump runs fine, valve works fine BUT the Ford joystick will not work properly with the new valve. The float postion is on the first spool in the block. I has special INLET/OUTLET ports ported on top so that I could mount it upside-down so the float spool will be second for the joystick linkage to work. Well, the original float (Husco) worked when the spool was pulled. The new cross float works when the spool is pushed.