Bad seal on brush hog gearbox?

IronRyan

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Equipment
Kubota 3560
Apr 1, 2023
46
25
8
Tennessee
MY bush hog sat for several years. When i got back into it, I cleaned it up and changed the gear oil out of the gearbox, but now this is happening. Is this a bad seal? How do i go about repairing it?
 

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GreensvilleJay

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Equipment
BX23-S,57 A-C D-14,58 A-C D-14, 57 A-C D-14,tiller,cults,Millcreek 25G spreader,
Apr 2, 2019
11,419
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113
Greensville,Ontario,Canada
yes, bad seal...
basic repair process....

order seal and case gasket
drain oil..
remove Ujoint

clean shaft real good(fine sandpaper)
to me it looks 'rusty/rough',bits got into seal,

remove 4-5-6(?) bolts
slide housing forward ,off shaft

clean shaft again, be sure it's smoother than a baby's butt !!!

pop out seal, install new one
reinstall housing
refill oil

overall not a bad job, you'll spend 1/2 time 'polishing' the shaft to be 100% sure it's smoooooooth !
 
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Norman

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LX2610HSD;LA535;LP 60" grapple; WC68 chipper; GB60 SW cutter
Sep 30, 2021
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Georgia, USA
Looks like it is a bad seal. There are some good youtube videos out there that show how to replace seals on brush cutter gear boxes I would search out there. I've seen two methods, one is where you remove the upper gear from the housing (those bolts on the vertical surface) which gives you access to the seal (in some cases). The second is using a metal screw tapping into the seal itself from the outside and then using a claw hammer or pliers to pull the seal out using the screw. On my gear box I used the first method and it worked fine for me.
 
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D2Cat

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Buy a tube of corn head grease (at your local John Deere dealer) and use the whole tube.
 
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N3BP

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B7200DT, B7200HST-D, L2900GST, L3010 HST TLB
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Check the input shaft for excessive play. That will cause a seal to fail as well.
 
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IronRyan

Member

Equipment
Kubota 3560
Apr 1, 2023
46
25
8
Tennessee
yes, bad seal...
basic repair process....

order seal and case gasket
drain oil..
remove Ujoint

clean shaft real good(fine sandpaper)
to me it looks 'rusty/rough',bits got into seal,

remove 4-5-6(?) bolts
slide housing forward ,off shaft

clean shaft again, be sure it's smoother than a baby's butt !!!

pop out seal, install new one
reinstall housing
refill oil

overall not a bad job, you'll spend 1/2 time 'polishing' the shaft to be 100% sure it's smoooooooth !
Thanks alot!
 

Runs With Scissors

Well-known member

Equipment
L2501 TLB , Grappel, Brush Hog, Box Blade, Ballast box, Forks, Tiller, PH digger
Jan 25, 2023
2,437
2,816
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Michigan
Buy a tube of corn head grease (at your local John Deere dealer) and use the whole tube.
For folks like me, who know very little about tractors, the obvious question is.........What does that do?
 

GreensvilleJay

Well-known member

Equipment
BX23-S,57 A-C D-14,58 A-C D-14, 57 A-C D-14,tiller,cults,Millcreek 25G spreader,
Apr 2, 2019
11,419
4,908
113
Greensville,Ontario,Canada
Maybe it's to replace the proper oil and it's soooo thick ,it'll never ooze out the damaged seal ??
If so, it's a backyard bodge NOT the correct way to FIX the problem...
 

William1

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BX25D
Jul 28, 2015
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Richmond, Virginia
Before I 'fix' anything like this, are you sure you have the right amount of oil in it? Was it empty when you tried to drain it? Is there a plug on the side to set the oil level'?
My point being if over filled, it will leak due to expansion. There has to be air space above the oil bath.
 
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RCW

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Apr 28, 2013
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Before I 'fix' anything like this, are you sure you have the right amount of oil in it? Was it empty when you tried to drain it? Is there a pug on the side to set the oil level'?
My point being if over filled, it will leak due to expansion. There has to be air space above the oil bath.
Good point. Looks like some space in that gear box is taken up by water, which is not uncommon.
 

IronRyan

Member

Equipment
Kubota 3560
Apr 1, 2023
46
25
8
Tennessee
Before I 'fix' anything like this, are you sure you have the right amount of oil in it? Was it empty when you tried to drain it? Is there a pug on the side to set the oil level'?
My point being if over filled, it will leak due to expansion. There has to be air space above the oil bath.
It's possible. I don't think so, but i do remember something funny happening when i filled it, but i can't remember exactly what happenend.
 

Tx Jim

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Maybe it's to replace the proper oil and it's soooo thick ,it'll never ooze out the damaged seal ??
If so, it's a backyard bodge NOT the correct way to FIX the problem...
Back yard or front yard repair I've had cornhead grease in my JD 709 rotary mower that has a faulty blade shaft seal for several years. While operating cutter cornhead greases liquifies some & when machine sits it solidifies. Cornhead grease has been used for over 40 yrs so it has it's value.
 
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Flintknapper

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L2350DT
May 3, 2022
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Deep East Texas
Back yard or front yard repair I've had cornhead grease in my JD 709 rotary mower that has a faulty blade shaft seal for several years. While operating cutter cornhead greases liquifies some & when machine sits it solidifies. Cornhead grease has been used for over 40 yrs so it has it's value.
^^^^^

Yep.

 

Motion

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Kubota MX5100HST/FEL
Aug 17, 2020
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Mandeville Louisiana
As others have said clean it really well and polish the seal area with Crocus cloth, use a double lip seal, if it's available in that size. If the shaft has fretting use a Speedi-sleeve. Ensure the gear box vent functions.
 
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Runs With Scissors

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L2501 TLB , Grappel, Brush Hog, Box Blade, Ballast box, Forks, Tiller, PH digger
Jan 25, 2023
2,437
2,816
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Michigan
As others have said clean it really well and polish the seal area with Crocus cloth, use a double lip seal, if it's available in that size. If the shaft has fretting use a Speedi-sleeve. Ensure the gear box vent functions.
I have never heard of a Speedi-sleeve.

Thanks for posting that, it may come in handy some day!

^^^^^

Yep.

I was going to say, Interesting "get around", especially if your ever in a pinch.


Back yard or front yard repair I've had cornhead grease in my JD 709 rotary mower that has a faulty blade shaft seal for several years. While operating cutter cornhead greases liquifies some & when machine sits it solidifies. Cornhead grease has been used for over 40 yrs so it has it's value.
But apparently it works very well. (y)
 
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Flintknapper

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L2350DT
May 3, 2022
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Deep East Texas
If the input seal is leaking.....then the output shaft (underneath the deck) probably is too. The output shaft seal is hidden by the 'stump jumper' (if the cutter is so equipped) so you can't see it to verify.....but it is probably leaking also.

It is MUCH harder to get to.....so some folks look for an alternative. Corn Head grease is a semi-liquid grease and can be a good answer for those not equipped to perform the proper repair (or just don't want to).

It isn't necessarily a 'band-aid' fix, JD uses the grease for lubrication in some of their brand new implements with gears sets.
 
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hedgerow

Active member
Jan 2, 2015
277
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43
Malcolm NE
I have a fifteen foot flex wing mower that came from the factory with corn head picker grease in all the gear boxes. I don't have a gear box on the farm that doesn't have corn head picker grease in it. Always make sure you don't have any moisture in your gear boxes and that the vents aren't plugged up. I have seen many of gear boxes leak because of a plugged vent.
 
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