Advice On How To Straighten Gearbox. Deck Mounting Point Bent Slightly.

[wirlybird]

Hi all,
I have a 6 foot brush bull similar to the one in the picture.
While doing some repair work I find that the gearbox is leaning to one side. If you stand at the front or back you can see it leans a little, like the arrow in the picture.
I can see where the deck is lifted slightly on one side where the gearbox mounts.

What would be the best way to straighten this back up?
Pull the gearbox and hammer the one side of the deck back down?
Somehow get leverage on the gearbox and try to pull it back into place?

I don't know how it got bent since it was likely this way when I got it this past fall. It is in good condition but the stump jumper did have a dent in it so maybe something got jammed up underneath?

Anyway, wanted to get some opinions before diving into fixing it. Thanks!

 

[sea2summit]

I wouldn't pull on the gear box.

I'm not a metallurgist but I'm guessing the "right" way would be to remove the gear box, heat the deck with a torch, bend it back straight with a pry bar or clamping it to something to pull it back.

 

[Jims1025R]

Yup, don't pull on the gearbox!

Remove it. It may be a fight to return the deck, it has stretched now, and won't want to sit flat ever again. You might hammer it closer, and sure, do that. Do it cold, heating it will not help you enough to be worth it, 'cause it's never going to be perfect again (you can bend the sheet, but you cannot compress it back).

Once you're as close as you can get, shim the gearbox to be level with washers. Just be sure that the surface (accumulated washers) is as flat for the gearbox as possible.

 

[mrmikey]

I'd remove the gearbox, get a long 4 x 4 or something strong, put a short length of something similar under the middle of the 4 x 4 above the dented area (like a teeter totter) and chain the end of the long 4 x 4 to the opposite corner of the deck. As you push down on the opposite end of the 4 x4, get someone to hammer on the dent around where you have the shorter length of 4 x 4 placed forcing it down. You'll probably have to attach it to the tractor to keep it stable as you work and pry on it.
IMHO, I wouldn't heat it as I'd bet you're gonna cause cracks eventually, just my thoughts for whatever they're worth ............Mike

 

[wirlybird]

Here are a couple pictures of the underside.
In one you may be able to see how the output shaft is leaning slightly to the left.
In the other picture, the two bolts circled which is the left side as in the other picture, are the area that has "cupped" down a bit.
This is the area that needs to be "pushed" back down from the top.
It is pretty minor but it does make the stump jumper off about 1/2 to 3/4 of an inch from one side to the other.

 

[sea2summit]

Dang, that sucker hit something hard!

If you're really committed you could cut out the bent c-channel and put in a new piece then force that deck flat!

 

[wirlybird]

Dang, that sucker hit something hard!

If you're really committed you could cut out the bent c-channel and put in a new piece then force that deck flat!

Yea, I really don't know what happened. The stump jumper did have a good, sharp bend on the outer edge in one spot.
Maybe a hunk of wood or something got jammed between it and the main body?
Bearing for the output shaft looks good and is tight. Output shaft spins true so it is ok.

 

[sea2summit]

Yea, I really don't know what happened. The stump jumper did have a good, sharp bend on the outer edge in one spot.
Maybe a hunk of wood or something got jammed between it and the main body?
Bearing for the output shaft looks good and is tight. Output shaft spins true so it is ok.

Easiest answer is probably just shim it so the blades are rotating parallel to the deck and call it a day.

 

[npalen]

Here are a couple pictures of the underside.
In one you may be able to see how the output shaft is leaning slightly to the left.
In the other picture, the two bolts circled which is the left side as in the other picture, are the area that has "cupped" down a bit.
This is the area that needs to be "pushed" back down from the top.
It is pretty minor but it does make the stump jumper off about 1/2 to 3/4 of an inch from one side to the other.

View attachment 740720

View attachment 740721

Might try removing the gearbox and then stick a pair of 1/2", or so, eyebolts down thru the two holes mentioned. With a loop of logchain attached to the eyebolts (or hexbolts might work also) stick a long prybar under the loop, heat the area between and around the two bolts then bend the channel back straight checking with a straightedge?

 

[WranglerX]

Do not pull on gear box, its most likely cast iron and brittle, you can shatter it..... I'm in favor of the already suggested heat and beat to straighten mounting deck...

You may not even need to heat.... Got 8lb sledge, a few good whacks may solve the problem....