Backhoe hydraulic problem

[Tom_W]

I purchased a SMC(rhino) 65A backhoe about a year and a half ago. So far I am very pleased with it's performance. Recently, it has developed annoying sound. When ever any of the controls are pulled back when the corresponding piston is all the way in, there is a chattering sound. At first it was only the boom lever control that created this sound. I thought that it might be dirt in the system so I changed the oil and filter. Still the same. Does anyone there have any ideas as to what might be my problem? The tractor that it's mounted to only has about 115 hours so the backhoe might have 50 hours at most but I am sure it's less. I am a home owner not a business. Any help in this matter would be greatly appreciated.

 

[PineRidge]

If your cylinders move as they were intended but you only hear the noise when the cylinders are either fully extended or fully retracted then I would guess that you might be hearing the relief valve on the backhoe itself.

 

[Tom_W]

That makes sense. But how come I never heard it before? If it's failing, are they hard to replace or rebuild? I should add that my backhoe runs off a pto pump not from the tractor.

 

[PineRidge]

The backhoe relief valves are installed in the valve body itself, at least on my New Holland, and I would guess yours too. I wouldn't be as concerned about a little noise at the extreme ends of cylinder travel (mine makes a high pitch whistle under those conditions) but if I thought that I was losing digging force because of a faulty relief then I would deal with it.

My backhoe reliefs can be serviced (cleaned) but cannot be adjusted.

 

[Tom_W]

Thanks for the input. It sets my mind at ease somewhat. One more question, The relief valve is on the supply or return side of the valves? Now I'll take it off for the winter and put my rear blade on for the driveway. I can't believe we got snow friday night. It's still around today in the shady areas. I'm only about 10 miles from Long Island Sound, so we shouldn't see snow that sticks for about 3-4 weeks.

 

[PineRidge]

Tom for the exact location of your relief valve you would need to look at a SMC backhoe parts breakdown for the control valves. My New Holland backhoe uses 5 relief valves within the gang of 8 valves. When you purchased your SMC backhoe were you furnished with the operators manual?

 

[Tom_W]

After looking forever to find the manual, I see what you are talking about. However, the outrigger controls also cause this sound and I don't see relief valves for them. That would make it the main relief valve. Right? Any way, I included a pic of what's in the manual so you can see what I'm looking at. It shows 16 17 are work port reliefs. 18 is the main relief.

 

[PineRidge]

Yikes your control valve is exactly the same as the one on my New Holland. I'm now wondering how many different manufacturers use this same group of valve bodies? Anyway the main backhoe relief is number 18 as you said and it is set at 2000 PSI.

When you move your stabilizers without reaching the end of the travel on the stabilizer cylinders do you still hear the noise?

 

[depratt_equip]

Rhino makes some loaders and backhoes for NH. Yours might actually be a Rhino backhoe. If I saw a picture of it I would be able to tell ya.

*EDIT* - Just took a look at your pictures on the internet of your backhoe and its a Rhino hoe.

 

[PineRidge]

I wonder how many other names are on Rhino backhoes?

Wait a minute I've never seen a <font color="blue">blue </font> rhinoceroses before. /forums/images/graemlins/tongue.gif