pressure relief valve B7800

   / pressure relief valve B7800 #1  

atgvir

Member
Joined
Feb 21, 2007
Messages
28
Location
Virginia
Tractor
Kubota L4240 HST
Could some one please tell me where to locate the pressure relief valve on a B7800 for the lift hydraulics. Also, does any one have the range the hydraulics can operate in on the 7800. I want to increase my lift capacity on the la402 loader and don't want to exceed the max. pressure. I plan on using a gauge and changing the shims to get max pressure.

Thanks,
 
   / pressure relief valve B7800
  • Thread Starter
#2  
Please guys. Anyone out there that has a service manual for the 7800 that can look up the pressure range on the hydraulics for the 3pt hitch and loader.

Thanks,
 
   / pressure relief valve B7800 #3  
Could some one please tell me where to locate the pressure relief valve on a B7800 for the lift hydraulics. Also, does any one have the range the hydraulics can operate in on the 7800. I want to increase my lift capacity on the la402 loader and don't want to exceed the max. pressure. I plan on using a gauge and changing the shims to get max pressure.

Thanks,

The relief is in the pressure control valve. The relief setting is 1920-1991psi according to the service manual, so that must be the max pressure.
 
   / pressure relief valve B7800
  • Thread Starter
#4  
Thanks so much. That is what I needed.:D
 
   / pressure relief valve B7800 #5  
Here is the parts list for your loader. Hope it opens.
 

Attachments

  • B7800 LA402[1] Loader Parts.pdf
    469.5 KB · Views: 816
   / pressure relief valve B7800
  • Thread Starter
#6  
LeeJohn,

Thanks for the parts manual. Does any one know if the relief valve for the 3pt hitch also control the loader. I have the parts manual for the tractor and did find the valve for the 3pt hitch. I have read that most Kubota tractors use the same relief valve for the 3pt hitch and front loader.

Thanks
 
   / pressure relief valve B7800 #7  
Look on page 126 and 127 of your parts manual and see if that tells you anything.
 
   / pressure relief valve B7800 #8  
LeeJohn,

Thanks for the parts manual. Does any one know if the relief valve for the 3pt hitch also control the loader. I have the parts manual for the tractor and did find the valve for the 3pt hitch. I have read that most Kubota tractors use the same relief valve for the 3pt hitch and front loader.
Thanks

Based on my admittedly elementary understanding of hydraulics, it would seem dangerous to not have a pressure relief valve on every control valve. My reasoning is that if you were operating the loader, there would be no flow through the power beyond port to the 3pt, so that relief valve could be of no help if the system over pressurized.
 

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