Underpowered 3901 Tractor with BH77 Backhoe (or design flaw)??

minthral

Active member

Equipment
Kubota L47
Nov 22, 2021
189
92
28
NC
I have l3301 with BH77, third function, and 2 rear remotes. Backhoe easily overpowers the tractor. 2 functions are easy and quick. Can do 3, but it really slows down plus that’s not easy and takes lots of skill/practice. Now that I’m familiar with it, I’m doing WOT and can go pretty quick (becomes muscle memory).

I think they plumbed the hydraulics wrong on yours. Make sure the power better beyond port (left most on hydraulic block under floor board goes straight to backhoe). This is the power out port. Make sure other connection is from remotes. This is the power in port.
Also have them check hydraulic pressure. They’re all low from factory and can be adjusted up.
 

TheOldHokie

Well-known member
Lifetime Member

Equipment
L3901/LA525, B7200DT/B1630, G2160/RCK60, G2460/RCK60
Apr 6, 2021
6,961
3,353
113
Myersville, MD
windyridgefarm.us
I have l3301 with BH77, third function, and 2 rear remotes. Backhoe easily overpowers the tractor. 2 functions are easy and quick. Can do 3, but it really slows down plus that’s not easy and takes lots of skill/practice. Now that I’m familiar with it, I’m doing WOT and can go pretty quick (becomes muscle memory).

I think they plumbed the hydraulics wrong on yours. Make sure the power better beyond port (left most on hydraulic block under floor board goes straight to backhoe). This is the power out port. Make sure other connection is from remotes. This is the power in port.
Perhaps I am misunderstanding your description but the port under the floorboard is pressure return from the implement and powers the 3pt. The connection from the remotes is pressure out (power beyond) which powers the backhoe.

Dan
 

minthral

Active member

Equipment
Kubota L47
Nov 22, 2021
189
92
28
NC
Perhaps I am misunderstanding your description but the port under the floorboard is pressure return from the implement and powers the 3pt. The connection from the remotes is pressure out (power beyond) which powers the backhoe.

Dan
Dealer installed mine with return pressure from BH going to power
beyond port directly on the block under floorboard (left most connection). If yours isn’t, you might have backpressue.
 

TheOldHokie

Well-known member
Lifetime Member

Equipment
L3901/LA525, B7200DT/B1630, G2160/RCK60, G2460/RCK60
Apr 6, 2021
6,961
3,353
113
Myersville, MD
windyridgefarm.us
Dealer installed mine with return pressure from BH going to power
beyond port directly on the block under floorboard (left most connection). If yours isn’t, you might have backpressue.
Perhaps this is semantics. The left most connection on the hydraulic block under the floor board is pressure return for the 3pt valve. When the backhoe is connected the 3pt valve is locked down to prevent creating back pressure on the tank port on the backhoe valve.

Pressure flow is rightmost port (pump) on hydraulic block to pressure in on loader valve. Power beyond on loader valve to pressure in on remote valves. Power beyond on remote valves to pressure in on backhoe valve. Tank return on backhoe valve to pressure return on hydraulic block. When the backhoe is removed power beyond on remote valves is connected to pressure return on hydraulic block which supplies pump pressure to the 3pt.

Dan
 
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MapleLeafFarmer

Well-known member

Equipment
Lots incl. B and L kubotas
Dec 2, 2019
560
415
63
E.
Any other implements attached?
I have lots of attachments but when the BH77 is attached I would normally have on the front loader the 66" light material bucket or a EA Wicked root grapple operated with the Landpride 3rd function system or a set of forks.
cheers
 

ayak

Well-known member
Lifetime Member

Equipment
L3301 HST
Feb 16, 2018
574
746
93
WV
Perhaps this is semantics. The left most connection on the hydraulic block under the floor board is pressure return for the 3pt valve. When the backhoe is connected the 3pt valve is locked down to prevent creating back pressure on the tank port on the backhoe valve.

Pressure flow is rightmost port (pump) on hydraulic block to pressure in on loader valve. Power beyond on loader valve to pressure in on remote valves. Power beyond on remote valves to pressure in on backhoe valve. Tank return on backhoe valve to pressure return on hydraulic block. When the backhoe is removed power beyond on remote valves is connected to pressure return on hydraulic block which supplies pump pressure to the 3pt.

Dan
You’re spot on here, Dan.
My 3301 came to me from the dealer with a FEL and BH77.
The tractor’s main hydraulic block ‘out’ fed the FEL. Then the FEL’s PB port fed the BH77 (as it came to me).
I ordered in all the kits from Kubota and the Kubota directions themselves for adding the Rear Remotes have you running the FEL PB now instead to the Inlet port of the Rear Remote block (near the seat). You then take the PB port from that Rear Remote (sandwich) block and run a hose over to the BH77 inlet. And the BH77 outlet hose then runs over to the tractor’s main hydraulic block on the side, where it then goes to the 3pt. (must be the reason the 3-pt is required to be ‘down’ if using the BH).
 
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