Not impressed with my B77

[Hammer Head]

Had my first chance today to really use my B77.
My project was to cut down a 15" River Birch and remove the stump. My grandmother could have removed the stump quicker with a pick and shovel.
My Kubota replaced a Ford 1720 with a Bushog 7'-6" 3 Pt. Mtd. Hoe with PTO pump, that had twice the power!!
Is there any way to improve the Hydro. pressure to the hoe or should I just consider selling and replacing it with another brand hoe with PTO pump?
I am 99% sure that everything is working properly with only 11Hrs. on the meter. I was impressed with the power of the outriggers but they are not doing the digging.

Jeff

 

[dodge man]

What are you comparing it to? A construction grade machine? Keep in mind it's a compact tractor. You can shim the pump pressure but of course that's might be pushing the limits.

 

[Hammer Head]

What are you comparing it to? A construction grade machine? Keep in mind it's a compact tractor. You can shim the pump pressure but of course that's might be pushing the limits.

Just comparing it to my early 1990s ford 1720 with 7'-6" Bushog, I bought the Kubota because the
old ford and hoe had seen it's better days. Even with worn valves and leaking seals it could still out dig the B77.

What do you mean by shim the pump??

 

[Gary Fowler]

Does the hoe lack power or SPEED. If it is power, then have the dealer adjust the pump pressure to maximum. This is done by putting shims under the relief valve on the hydraulics to adjust the spring tension needed to "pop" the relief valve. Unless you have gauges and flowmeters it is best done by the dealer.
The Kubota may never run as fast as the Bushhog hoe with external pump. Your flow will never be more than the tractors hydraulic system limits regardless of the pressure setting. Your Kubota is likely around 8 GPM or LESS for the hoe so it isn't going to act like one with 12-15 GPM.

 

[Hammer Head]

Speed seams to be good, it is just lacking power. When hard digging I normally run the tractor just at the PTO mark on the RPM gauge.
The same with the old Ford.
Even with the lower GPM internal pump. I would think?? it would only affect the speed not pressure??
Could I shim the pump my self? I have access to the gauges and have fairly good mechanical skills.

 

[Gary Fowler]

You can get a shim kit from your dealer and do it yourself. On my B26, the PRV is under the tractor and to get to it requires removal of the right rear tire and your tractor might be similar. You need to place jacks under the frame for safety prior to removing the tire and removing the PRV housing so you can adjust the shim pack. IIRC each 1mm shim increases the pressure approximately 25 PSI. It isn't a difficult task if you can get up and down and crawl under the tractor easily (that is pretty difficult for my old arthritic body)

 

[Hammer Head]

Thanks Gary
There is a Alum. block under the right foot well with all of the hoses running from it. I assume it is the return line you are talking about?
How many shims can be added? 25 PSI does not seam like much.
Jeff

 

[Gary Fowler]

Thanks Gary
There is a Alum. block under the right foot well with all of the hoses running from it. I assume it is the return line you are talking about?
How many shims can be added? 25 PSI does not seam like much.
Jeff

THe valve would be designed and set for a specific pressure, you would only be adjusting it to compensate for weakening of the spring. Usually (per TBN comments) they are not off more than 200 PSI. Shim kits will contain some various thickness spacers. There should be at least 1 that is 1/8" thick. YOU would need to measure your current max pressure. I did this by hooking a gauge to my stabilizer hose since the fitting was compatible with my gauge. Then depending on what the shim kit for your tractor says, figure the amount of shims needed, install them and then test the pressures. DO not exceed the max pump pressure per your tractor.

By the way, the distribution block may not house the PRV valve. It did on my old Vietnam rebuilt Yanmar, but I doubt your Kubota will.

 

[Hammer Head]

Do you know what the normal operating pressure -vs- Max. safe operating pressure would be for the L 3800
If I shim the pump, I would not want to go over the Max. and void my warranty.

 

[whis]

if its under warranty talk to your dealer