BH-77 Boom

Rolle

New member

Equipment
L3901-DT
Jan 17, 2022
3
1
3
Ocala, Florida
I am having an issue where the boom will not come up. I have a BH-77 mounted to a L3901 DT. On occasion the boom. Will not retract. I can see/feel it pulsating when pulling back on the stick. To get it working i shut the tractor off just for a few minutes, start the tractor back up and the boom wiil come back up. The boom has plenty of power to lift the back of the tractor up. No oil leaking from the backhoe. Any ideas on what the issue might be would be appreciated.
 

kubotafreak

Well-known member

Equipment
GRAND l6060, L3560, B6100, gr2100, tg 1860, g1800, g1900, g2160
Sep 20, 2018
1,049
402
83
Arkansas, US
If other functions on the BH work fine, and it is localized to the boom only, I would suspect the relief valve on port (A). Port (A) and port (C) share the same part, so you could try swapping them out to see if the problem follows(make sure boom and dipper are rested on the ground before doing any work to the BH).


port A.PNG
 
Last edited:

Rolle

New member

Equipment
L3901-DT
Jan 17, 2022
3
1
3
Ocala, Florida
Thank you for the advise. I am going to try swapping them out. Thanks again
I swaped the relief assembly like Kubotafreak suggested. The boom works correctly now but suprisingly the stick works okay also which was the relief valve that was switched with the boom valve. I am going to purchase a new valve assembly anyway, maybe just have it in the tool box. $420 is a pretty steep price though.

Thank you Kubotafreak for your suggestion.
 
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kubotafreak

Well-known member

Equipment
GRAND l6060, L3560, B6100, gr2100, tg 1860, g1800, g1900, g2160
Sep 20, 2018
1,049
402
83
Arkansas, US
Glad it was an easy fix, sometimes they get fod in them. There is a tiny check pintle at the end. I wouldnt be suprised if disassembly, and reassembly unstuck it. Oh, and the reason kubota sells the whole thing, is because they are sold preset per function. Other than that they are the same. You can measure with a caliper the depth of the adjustment nut and get a good ballpark of psi setting. I would inspect before dropping 500 on one. Good luck!
 

lugbolt

Well-known member

Equipment
ZG127S-54
Oct 15, 2015
5,515
2,228
113
Mid, South, USA
they usually get a pieces of trash in the valve. I've taken them apart before and found the trash, for pictures. It's usually TINY.