# disk mower whines when raising



## aldent (Mar 15, 2015)

I have a 415 new holland disk mower conditioner and I use a 390 T massey ferguson 4x4 When I am mowing hay and I go to raise the mower up at the end of a field, I hear a loud whining noise, have not figured out if its the tractor or the mower, especially since it was this past summer. I bought the tractor and the mower last summer, so I have never had this problem. If I raise the mower at the shop or barn it does not make the noise, But when the tractor is all warmed up and were cutting it will do this. Any ideas. I had one friend tell me it could be a breather on the tractor. He had similar happen to him.

Thanks for any comments or ideas


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## glasswrongsize (Sep 15, 2015)

aldent said:


> I have a 415 new holland disk mower conditioner and I use a 390 T massey ferguson 4x4 When I am mowing hay and I go to raise the mower up at the end of a field, I hear a loud whining noise, have not figured out if its the tractor or the mower, especially since it was this past summer. I bought the tractor and the mower last summer, so I have never had this problem. If I raise the mower at the shop or barn it does not make the noise, But when the tractor is all warmed up and were cutting it will do this. Any ideas. I had one friend tell me it could be a breather on the tractor. He had similar happen to him.
> 
> Thanks for any comments or ideas


Spitballing here- I got the wrong Hyd Oil in my backhoe and it squalled like a banshee after it warmed a bit because the fluid got foamy... at least that's what I think. Changed the oil and fixed the problem.

73, Mark


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## aldent (Mar 15, 2015)

worth checking into Thanks


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## thendrix (May 14, 2015)

I was thinking maybe a low oil situation allowing the pump to whine. If you're pumping foam you'd probably have the same thing as pumping nothing.

Is there another application you use this tractors hydraulics for? Same result or different?


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## Wethay (Jul 17, 2015)

Okay, most likely a stupid question, your lift is going all the way up so it's not a relief valve making the noise. Warmer oil, or higher flow because of higher rpm causing the noise, maybe?


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## slowzuki (Mar 8, 2011)

Mine whines when raising at high tractor rpm because the restrictor valve in the mower makes the relief valve on the tractor kick in.


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## mlappin (Jun 25, 2009)

slowzuki said:


> Mine whines when raising at high tractor rpm because the restrictor valve in the mower makes the relief valve on the tractor kick in.


Possibly could have a weak relief valve, I wouldn't think a MF390 would have that high a performance hydraulics on it, so could be a weak relief. Does the raising of the mower slow down when warm?


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## aldent (Mar 15, 2015)

all good possibilitys It usually only does it when its at high rpm and when I am cutting so I will check a couple of those ideas. The hyd oil is full, That Is for sure and it is not foaming cause I would have seen that in the oil when I checked it. The relief sounds like a possiblility

Thank you all


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## slowzuki (Mar 8, 2011)

The 390 is open centre so you pull the lever at high rpm the full pump flow is thrown at that circuit. There is usually a restrictor or little lines on the disc mower so it isn't thrown around really fast. That restrictor means full flow can't go into the circuit so it has to go out the relief valve or the pump would overpressurized.

Once the oil gets hot it should raise slightly faster but not much as the thinner oil can flow through a simple orifice restrictor faster.



mlappin said:


> Possibly could have a weak relief valve, I wouldn't think a MF390 would have that high a performance hydraulics on it, so could be a weak relief. Does the raising of the mower slow down when warm?


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## aldent (Mar 15, 2015)

Thank you all for your ideas and input. I'll talk to the Massey dealer about the restrictor. Thanks again.


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## slowzuki (Mar 8, 2011)

Don't take it out or the mower will slam to the ground when you lower it.


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