B7100D Rear Implements Drift Down

[rcsroper]

My B7100D purchased new in 1974 has 2080 hours ... I notice implements won't stay put and drift down. I adjust lowering speed with the hydraulic needle valve when I change from tiller to box scraper. I suspect leakage in the control valve itself causing problem. So ... is there anything simple I can try before taking it in to a dealer?

Thanks in advance for your help.

Rick

 

[North Idaho Wolfman]

More likely the cylinder or rings are the issue.
Pull the cover and inspect.

Taking that to a dealer would be a pretty costly event.

 

[TheOldHokie]

My B7100D purchased new in 1974 has 2080 hours ... I notice implements won't stay put and drift down. I adjust lowering speed with the hydraulic needle valve when I change from tiller to box scraper. I suspect leakage in the control valve itself causing problem. So ... is there anything simple I can try before taking it in to a dealer?

Thanks in advance for your help.

Rick

Raise any implement and completely close the lowering valve. If it still leaks down its the cylinder.

Valve problems on those models is usually loss of tension in the lever itself.

Dan

 

[rcsroper]

My B7100D purchased new in 1974 has 2080 hours ... I notice implements won't stay put and drift down. I adjust lowering speed with the hydraulic needle valve when I change from tiller to box scraper. I suspect leakage in the control valve itself causing problem. So ... is there anything simple I can try before taking it in to a dealer?

Thanks in advance for your help.

Rick

More likely the cylinder or rings are the issue.
Pull the cover and inspect.

Taking that to a dealer would be a pretty costly event.

There is no hydraulic cylinder, only a hydraulic control valve shown on page 45 of the original parts manual. There is a "spool" (part #66611-3629) operated by the up down lever which must direct hydraulic pressure from the pump mounted at front of tractor. The control valve parts diagram shows an "adjusting screw" (#66591-3636) accessible from a small removable cover. It must increase/decrease spring (66591-3635) pressure, but it's not clear what affect that has on the implement hydraulics.

See attached parts diagram for "control valve group"

Raise any implement and completely close the lowering valve. If it still leaks down its the cylinder.

Valve problems on those models is usually loss of tension in the lever itself.

Dan

 

[TheOldHokie]

There is no hydraulic cylinder, only a hydraulic control valve shown on page 45 of the original parts manual. There is a "spool" (part #66611-3629) operated by the up down lever which must direct hydraulic pressure from the pump mounted at front of tractor. The control valve parts diagram shows an "adjusting screw" (#66591-3636) accessible from a small removable cover. It must increase/decrease spring (66591-3635) pressure, but it's not clear what affect that has on the implement hydraulics.

See attached parts diagram for "control valve group"

The "spool" is the valve and it operates a hydraulic cylinder.

Close the lowering control valve and see if leakdown stops.

Dan

 

[Russell King]

@rcsroper

The 3PH cylinder is inside the tractor, not an external hydraulic cylinder like on a front end loader

You can find it in the illustrated parts list that is available here

Kubota Tractor Corporation - Illustrated Parts List

- K-PAD - Parts Lists - Illustrated Parts Lists - diagrams

apps.kubotausa.com

Here is a screenshot of the parts on my L185 since the similar diagram for your tractor was less clear than these two. The blue shows the speed control apparatus that is over the cylinder that is in the yellow. The piston goes into the cylinder (but is pulled to the side for illustration purposes).

 

[North Idaho Wolfman]

There is no hydraulic cylinder, only a hydraulic control valve shown on page 45 of the original parts manual.

So you think the three point moves via magic pixie dust?

DO NOT open up the control valve and start "adjusting things" that not your problem, and no good will come of it.

The valves rarely have any issues and they rarely have any issue with the three point drooping and drifting.

The drop speed adjustment is external so no need to open it up and go searching for it, it's right out in the open.

@Russell King has the right idea but let's clear this up a bit.

This is a B7100 three point cylinder and piston and rings.

There is no drop speed control on the cover it's on the valve.

 

[torch]

I notice implements won't stay put and drift down.

Rick

Over what? Seconds, minutes, hours or days? They all drift down right from the factory, it's only a question of how fast they drift down.

For comparison, my B7100 with similar hours will take about 2 days for the 3ph to fully drop a 400lb snowblower from max lift to the ground.

 

[TheOldHokie]

Over what? Seconds, minutes, hours or days? They all drift down right from the factory, it's only a question of how fast they drift down.

For comparison, my B7100 with similar hours will take about 2 days for the 3ph to fully drop a 400lb snowblower from max lift to the ground.

I was/am surprised by the lack of leakdown on my L3901. It will seemingly hold for weeks on end. They must have done something creative....

Dan

 

[North Idaho Wolfman]

I was/am surprised by the lack of leakdown on my L3901. It will seemingly hold for weeks on end. They must have done something creative....

Dan

Three point on the L drifts over a few days as does the B
But the real oddity is the 35year old Woods loader doesn't drift at all even over months.
And I got it used.

 

[torch]

But the real oddity is the 35year old Woods loader doesn't drift at all even over months.
And I got it used.

Maybe it's seized? <lol>

 

[rcsroper]

So you think the three point moves via magic pixie dust?

DO NOT open up the control valve and start "adjusting things" that not your problem, and no good will come of it.

The valves rarely have any issues and they rarely have any issue with the three point drooping and drifting.

The drop speed adjustment is external so no need to open it up and go searching for it, it's right out in the open.

@Russell King has the right idea but let's clear this up a bit.

This is a B7100 three point cylinder and piston and rings.

View attachment 164737



There is no drop speed control on the cover it's on the valve.

View attachment 164738

So you think the three point moves via magic pixie dust?

DO NOT open up the control valve and start "adjusting things" that not your problem, and no good will come of it.

The valves rarely have any issues and they rarely have any issue with the three point drooping and drifting.

The drop speed adjustment is external so no need to open it up and go searching for it, it's right out in the open.

@Russell King has the right idea but let's clear this up a bit.

This is a B7100 three point cylinder and piston and rings.

View attachment 164737



There is no drop speed control on the cover it's on the valve.

View attachment 164738

Wolfman ...
Thank you for your advice, the best being "... DO NOT open up the control valve and start "adjusting things" that not your problem, and no good will come of it." More than likely kept me out of trouble. Afterall, I was thinking "pixie dust" as I didn't see a cylinder. Now, in my parts book, I see the "oil group 2" which I've attached with "...group 1" that does show the cylinder. So, I've a better understanding of the 3 pt hitch.

I did close down the lowering needle valve as suggested by Dan and noticed my box scraper (about 200#) still drifted down in about 5 minutes while working with the front bucket. This drift concerned me as I had never seen any drift it in the 51 years I've owned the tractor.

All that being said, I ran tractor again today and found, to my surprise, the implement stayed in place with NO DRIFT DOWN WHATSOEVER. Temp is about 40 and the other day it was about 70 when I was working front bucket and noticed rear implement drift. Also noticed today my fluid level is about 20" below breather on hydraulic reservoir rather than the 4" recommended. No doubt low level is due to a small leak on one of my bucket tilt cylinders. So, I'll replenish reservoir and continue to wonder why the drift fixed itself.

Rcsroper

 

[TheOldHokie]

Wolfman ...
Thank you for your advice, the best being "... DO NOT open up the control valve and start "adjusting things" that not your problem, and no good will come of it." More than likely kept me out of trouble. Afterall, I was thinking "pixie dust" as I didn't see a cylinder. Now, in my parts book, I see the "oil group 2" which I've attached with "...group 1" that does show the cylinder. So, I've a better understanding of the 3 pt hitch.

I did close down the lowering needle valve as suggested by Dan and noticed my box scraper (about 200#) still drifted down in about 5 minutes while working with the front bucket. This drift concerned me as I had never seen any drift it in the 51 years I've owned the tractor.

All that being said, I ran tractor again today and found, to my surprise, the implement stayed in place with NO DRIFT DOWN WHATSOEVER. Temp is about 40 and the other day it was about 70 when I was working front bucket and noticed rear implement drift. Also noticed today my fluid level is about 20" below breather on hydraulic reservoir rather than the 4" recommended. No doubt low level is due to a small leak on one of my bucket tilt cylinders. So, I'll replenish reservoir and continue to wonder why the drift fixed itself.

Rcsroper

More confusion. Sounds like your loader is independent of tractor hydraulics.

Dan

 

[North Idaho Wolfman]

Also noticed today my fluid level is about 20" below breather on hydraulic reservoir rather than the 4" recommended.

Level should be measured with the dipstick.

I think Dan might have nailed it if your talking about the hydraulic fluid level in the tower of the loader.
That level and the pump that uses that fluid are NOT connected to the three point at all.

The Hydraulic fluid in the transmission above and the pump below control the three point.

 

[North Idaho Wolfman]

That is one antique of a parts manual.
Do not order parts via that manual, all the numbers will be wrong.
Also if you look at that parts book and they don't match what your looking at on the tractor, that's because that manual is so OLD that they changed parts drastically as time went along.

This is aa much better source for current parts and numbers.

Kubota Tractor Corporation - Illustrated Parts List

- K-PAD - Parts Lists - Illustrated Parts Lists - diagrams

apps.kubotausa.com

If your drift is coming and going it's most likely a worn set of rings on the cylinder.

 

[North Idaho Wolfman]

Maybe it's seized? <lol>

HAHAHA!