
Kubota B7800 Whinning and has no power
![]() | UpholsterRuss
Join Date: Dec 2022 Posts: 4 Paradise CA ![]() |
2022-12-06 201412
I bought Kubota B 7800 with LA402 Loader I have changed fluids and filters but it has low power will not drag bucket and barely moves in hi. Also shakey raising bucket and 3 way attachment. It sounds like it has air in the line when using actuator. Is it possibly something besides my $900 pump going out?
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Kubota B7800 Whinning and has no power
![]() | minimac
Join Date: Jun 2013 Posts: 104 ![]() ![]() |
2022-12-25 201420
Did it have all of those issues when you bought it or only after the fluid changes ? ....
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Kubota B7800 Whinning and has no power
![]() | Murf
Join Date: Dec 1999 Posts: 7249 Toronto Area, Ontario, Canada ![]() ![]() |
2022-12-25 201425
First thing I’d check is that something hydraulic is not ‘stuck’ in a position’dead-heading’ the hydraulics.
Next would be to double check that ALL hydraulic quick disconnects are properly connected.
If it operated normally prior to service I’d say a bad pump is unlikely the cause.
Best of luck. ....
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Kubota B7800 Whinning and has no power
![]() | UpholsterRuss
Join Date: Dec 2022 Posts: 4 Paradise CA ![]() |
2022-12-27 201426
No it it came on gradually
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Kubota B7800 Whinning and has no power
![]() | UpholsterRuss
Join Date: Dec 2022 Posts: 4 Paradise CA ![]() |
2022-12-27 201427
I checked the lines they are fine.
It has no power steering but it should have power steering. Also is worse backing up then going forward . I've got a line going into loader control that shakes & sounds like it is cavatating in it or something. If I put the bucket down and roll it forward to give the tractor a push to get going then it will go. But it won't take off in higher gears either.
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Kubota B7800 Whinning and has no power
![]() | UpholsterRuss
Join Date: Dec 2022 Posts: 4 Paradise CA ![]() |
2022-12-27 201428
How would I do that? I have a parts book but it's only blow up diagrams, no servicing help. I need a service and/or shop manual
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Kubota B7800 Whinning and has no power
![]() | Murf
Join Date: Dec 1999 Posts: 7249 Toronto Area, Ontario, Canada ![]() ![]() |
2022-12-28 201429
I’d be leaning towards the problem being the power steering (PS) box. I say that because typically the system is set up with the PS as the priority circuit for safety. The PS gets its power first, only then does the excess go to other things like the loader and motive power.
From the description you definitely have a hydraulic circuit dead-headed, that’s what’s robbing the hydraulic power. The noise you’re hearing is the pressure relief valve opening & closing at super speed.
One thought though, is the loader (or it’s control valve) a recent addition? I ask because I’ve seen something similar before when someone added the wrong type of valve. Some are ‘open center’ some are ‘closed center’, they cannot be switched.
Best of luck. ....
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