Bush Hog 286 splines still viable?

[DieselBound]

I was hitting some heavy brush (and high ground) and felt a significant judder. Nothing that has happened many times in the past. The speed had dropped down and I figured I'd just caught too much ground (which I had). I lifted the BH up and pulled forward figuring I was out of trouble. Set the mower back down and realized that it wasn't cutting. PTO shaft was spinning. Shut things down to find that the stump jumper was GONE! Took me, the wife and the dog to locate it in some heavy brush: it was VERY hard to find.

When I'd gotten this BH, a couple years ago, I noticed that the stump jumper was a bit loose so I tightened it up: I'm guessing that my mistake was that I didn't flip it over to do this- gravity wasn't helping me. Anyway...

Here are the stump jumper splines (a couple were showing fresh wounds from its departure from the shaft, but not sheared or broken, just roughed up (perhaps it was from the castle nut?).

Here's the gearbox shaft.


Does this look good enough to reassemble? I'd clean things up real well, and I'd reinstall with BH flipped over (and tighten with my impact).

 

[Exchanger]

It doesn't looks like so bad. Try to put one or two washer under the castle nut.

 

[bullbreaker]

If not : DN Equipment - DN Equipment

 

[RoyKing]

new stump jumper

 

[RickB]

Give it a try. Get it tight then smack the blade bar with a sledge hammer a couple times, then tighten. Repeat till you cannot get it any tighter.

 

[TMGT]

Actually they dont look too bad, remember they are tapered so it looks more worn in that picture. Might want to just clean them up a little with a file to make sure there aren't any burrs or distortion that would keep it from seating all the way.

 

[Zebrafive]

First time you tightened it did you put a cotter pin in? I can see the remains of one in the shaft picture.

 

[DieselBound]

I cleaned everything up and set the stump jumper back in place. The shaft is about 1/3" down from the top of the stump jumper's splines. Picture makes it look like the splines aren't lined up, but I just went out and took a look and it looks fine. Now I'm wondering whether I should pull it off and rotate it a bit to see if it wants to mate up better.


Zebrafive, yes, I'd put a new cotter pin in (I believe it was new- if not, it was in good enough shape) when I tightened it up: I don't recall how I tightened it up, maybe impact gun?

I ordered up a new castle nut and washers. Based on the price I'm hoping that the nut is a grade 10! I'm wondering how to go about torquing this up. The manual says that torque for a 30mm "fastener" (they show a bolt, but I figure it would apply to the nut) that is grade 10 (10.9) is 449 ft-lbs, grade 8 is 324 ft-lbs. I have 3/4" breaker bar and sockets, and I have a 1/2" air impact that's rated for 1,300 ft-lbs. Which should I look to use? (I know there's some way of calculating force for a breaker bar + cheater; perhaps this is the more appropriate way.) I don't want this coming off again as it's likely that if it happens again it'll for sure require some really expensive parts!

 

[RoyKing]

You to determine the amount of contact area and where it is. I would wire brush both parts and then dykem blue the shaft install and remove and inspect. You need contact at the top and bottom otherwise it will wobble and loosen

 

[DieselBound]

And if there isn't sufficient contact area (still not sure how I'd make that determination)? Would it be the stump jumper or the shaft? If it's the shaft then I really don't think that it's worth the headaches (juggling way too many things as it is): I got this thing pretty well beat up.

What is "normal" as far as how much I might expect the splined surfaces to draw together when torqued? As mentioned, I've got something like 1/3" (or perhaps 1/4") of the stump jumper above the end of the shaft's splines. Is it "normal" to have it start out with this much "gap?" I've never had a stump jumper off before, so nothing to compare to.