Backhoe KUBOTA L48 weak backhoe

   / KUBOTA L48 weak backhoe #1  

dougj7

Bronze Member
Joined
Oct 2, 2005
Messages
56
Location
Pine Bush, NY
Tractor
Kubota B2630
I was using my brothers L48 TLB today for the 1st time. The backhoe didn't seem to have as much power as I expected. There is a diagram that shows a directional valve lever position. In is for the backhoe and out is for the 3 point hitch. Is the valve located below the seat? They call it a lever, but the valve actually opens and closes but turning it. What rpm's should I be running when using the backhoe? Thanks for any help.

-Doug
 
   / KUBOTA L48 weak backhoe #2  
I was using my brothers L48 TLB today for the 1st time. The backhoe didn't seem to have as much power as I expected. There is a diagram that shows a directional valve lever position. In is for the backhoe and out is for the 3 point hitch. Is the valve located below the seat? They call it a lever, but the valve actually opens and closes but turning it. What rpm's should I be running when using the backhoe? Thanks for any help.

-Doug

I can't help on where the lever would be but guess on the right side. As far as rpm, that only makes a difference to the speed, but I run at around 1500 rpm normally.
 
   / KUBOTA L48 weak backhoe #3  
Not sure what you "expected" or what your experience is with other backhoes.

The L48 TLB is not a powerhouse. It is a mid-level BH at best with only 48 HP. But it will do a lot of work while taking more time than commercial, more powerful machines from Case and so forth.

Mine is run at about 1800 rpm when digging out large eucalyptus stumps (its main use).
 
   / KUBOTA L48 weak backhoe #4  
If the backhoe is operating then the lever should be in the correct position. Do the 3 pt cranks go up and down? It not, the lever is correct. I assume the 3 pt arms themselves are removed. Why do you say there is not as much power as expected?
 
   / KUBOTA L48 weak backhoe
  • Thread Starter
#5  
If the backhoe is operating then the lever should be in the correct position. Do the 3 pt cranks go up and down? It not, the lever is correct. I assume the 3 pt arms themselves are removed. Why do you say there is not as much power as expected?

There's a warning on the 3 pt raise/lower lever that says to lock it in the lowest position and don't move it with the backhoe attached.

The only thing I can compare the power to is my B2630 with a bh75 backhoe.. it seems to be more powerful than the L48. That's why I figure something isn't right.

Does anyone know where I can download a copy of the owners manual for the L48 TLB?

Thanks for the replies.
 
   / KUBOTA L48 weak backhoe #6  
There should definitely be a difference in the perception of power between the B2630/BH75 and the L48.

Bucket size may be part of the issue. Smaller buckets will seem to have more "power" when actually the force is applied in a smaller area. My 12" bucket digs appreciatively differently than the 24" bucket.

Some questions:
1. Do the stabilizers lift the rear wheels off the ground?
2. Does the front bucket lift the front wheels off the ground?
3. Will the boom lift the rear of the tractor higher with downforce on the bucket?
4. Does the BH bucket curl function cause the hydraulic pump to go into relief when the bucket meets resistance?
5. Is it the curl that seems weak?
6. How many hours is on the machine and when was the last hydraulic service done (fluid and filters)?
 
   / KUBOTA L48 weak backhoe #7  
If all controls are set as they should AND if really is weak, I would suspect that the relief valve needs setting. It is likely bypassing at lower pressure than it should. MY B26 has the same problem. It still has a good bit of power, but is appreciably lower than when new. A couple hundred PSI below max setting will make it seem weak. I suspect that the spring gets weaker with age and needs to be shimmed up a bit every few years to keep the pressures at max.
 
   / KUBOTA L48 weak backhoe
  • Thread Starter
#8  
There should definitely be a difference in the perception of power between the B2630/BH75 and the L48.

Bucket size may be part of the issue. Smaller buckets will seem to have more "power" when actually the force is applied in a smaller area. My 12" bucket digs appreciatively differently than the 24" bucket.

Some questions:
1. Do the stabilizers lift the rear wheels off the ground?
2. Does the front bucket lift the front wheels off the ground?
3. Will the boom lift the rear of the tractor higher with downforce on the bucket?
4. Does the BH bucket curl function cause the hydraulic pump to go into relief when the bucket meets resistance?
5. Is it the curl that seems weak?
6. How many hours is on the machine and when was the last hydraulic service done (fluid and filters)?

1. just barely
2. yes, easily
3. no
4. yes, I can hear the relief valve when raising the boom and dipper also
5. all of the motions for the backhoe seem weak including the stabilizers
6. It has around 120 hrs. My brother performed the fluid/filter change when he purchased it and has never used it since.

I'm thinking the relief valve is activating too soon. Is there a way to adjust it? What else can I check?
 
   / KUBOTA L48 weak backhoe #9  
On my L35, the bh/3pt lever comes out the back of the tractor. Behind the seat, below the deck. Takes a good push/pull to seat it. Knob in front of seat is for 3pt speed. Also check that the bh and any other quick connects are seated properly.
 
   / KUBOTA L48 weak backhoe
  • Thread Starter
#10  
Re: KUBOTA L48 weak backhoe - SOLVED

I found the solution to the weak backhoe problem on my brother's L48 in the owners manual page 37. But first I had to search his house to find the manual. The directional valve lever was not in all the way. After pushing it in, the backhoe has plenty of power.

I didn't see the lever at first due to it being blocked by the backhoe platform where you place your feet. To see the directional valve lever, I had to lean way over the platform with the access cover open. The swing lever is easy to see once the access cover is open.

Thanks for everyone's help.
 

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