Rotary Cutter Bush Hog 297 Problem

[Alanray]

Does anyone know if there are supposed to be bushings that the bolts fit through at the point where the tail wheel assembly attaches to the shredder/stabilizer arms. The dealership put bolts in but they've broken twice and this time the whole tail wheel assembly broke off and I bent my drive shaft.

I didn't even hit anything with the shredder - it's just from running it over rough ground. It seems as if there should be a sleeve or something that the bolt goes through. But all it came with and all the mechanic put back in after it broke were bolts.

I've attached a photo from the manual with an arrow at the problem point - anyone else have this problem?

 

[chh]

Generally there are just bolts in those holes. It sounds like you may have the brush hog riding with the tail too low. When it is lifted off the ground with the 3 point the back up should be higher than the front. Shorten the top link. The pivot adjustment should then flex and allow the tail to not slam the ground as hard and lift the tail if the tractor noses down. You may also want to slow down in the rougher areas. In really rough terrain you should be down into your lowest gears. First or second. If you are taking a beating a bouncing around you are going too fast. You should have the stabilizers on the 3 point set to reduce the bouncing side to side. It is generally very difficult to slam one of these around hard enough to bend a driveline.

 

[Robert_in_NY]

Check the settings like chh was mentioning to make sure you are not damaging this some how. If the bolt is too small for the hole then I would be worried as that will allow play and if the cutter slams down that slack will create forces that can shear bolts and tear metal. If you can find the problem and all your dealer does is put new bolts in then contact Bush Hog and ask them about it as Brush choppers really are not that complictated.

When you find out the problem can you please post what it is as it will be useful for others if they have a similar problem. So many times we get these types of questions and then no answer (I am assuming those are operator error as an answer and the operator is embarassed for various reasons )

Best of luck to you.

 

[Farmwithjunk]

I just bought one of those for my mowing business. There are no bushings as you mentioned. You've got SOMETHING out of whack if you're snapping tailwheels and bending PTO shafts. Any chance of posting a picture of the mower mounted on the tractor? I've tortured a Bush Hog 286 for 3 seasons now and haven't bent or broke the first part. Their products are typically well designed and tougher'n a $2 steak. That same tail wheel design has been in use on model 287 mowers for years with no design issues. I'd look at things like top link length, the "toggle" at the point where the top link attaches to the mower, and height setting of the tail wheel as starters.

Normally, the pair of struts running from the top of the A-farme to the tail wheel will buckle long before damaging the tail wheel if the tail wheel is loaded too heavy.

Also, look at the relationship between the PTO shaft and the front of the mower deck as you raise the mower. MANY mowers today will have the PTO shaft come in contact with the mower deck if the 3-point hitch is raised all the way to its maximum travel height. That wreaks havoc on the PTO shaft. Possibly you MAY not be able to raise the hitch to its highest point.

 

[Alanray]

Thanks, I'll take some photos tomorrow. I didn't bend the driveline until the A-frame struts became detached - I tried to raise the shredder and dangling tail wheels off the ground to drive back to the barn and that's when I bent the driveline. I should of just parked it.

Mine has one bolt holding the A frame strut and the tail wheel assembly to the shredder - one bolt on each side that is. There are, however, two holes - on each side. Does the strut and tail wheel assembly attach with a single bolt on each side or does the strut attach to one hole and the tail wheel assembly to the other hole?

 

[Farmwithjunk]

Thanks, I'll take some photos tomorrow. I didn't bend the driveline until the A-frame struts became detached - I tried to raise the shredder and dangling tail wheels off the ground to drive back to the barn and that's when I bent the driveline. I should of just parked it.

Mine has one bolt holding the A frame strut and the tail wheel assembly to the shredder - one bolt on each side that is. There are, however, two holes - on each side. Does the strut and tail wheel assembly attach with a single bolt on each side or does the strut attach to one hole and the tail wheel assembly to the other hole?

One bolt through one hole. Second hole (If we're talking about the same one) is for attaching some of the hardware for semi-mounted or drawn version of the mower.

For the record, what sort of tractor are you hitching this mower to?

 

[Robert_in_NY]

If you bent the driveline when you lifted the cutter then you must have lifted the cutter too high for the angle you had the mower set at. The tail wheels failing would have nothing to do with the bending of the pto as they would be lifted off the ground also when you lift the cutter. That part was operator error.

If you can, could you measure the size bolts they used as well as the hole they are suppose to go into? Also, check what grade the bolts are.

 

[Leejohn]

It sounds like your top link isn't adjusted right (too tight) and you went over a small hill or a small ditch. The weight of the rear of the tractor was put on the rear wheel of the mower. I did the same,but it broke the bars that run from the 3pt to the rear of the mower. I ended up using a chain for the top link.
Lee

 

[Alanray]

I'll measure them tomorrow - they were, I believe, Grade 5 bolts...three slashes on the bolt head.

 

[Alanray]

Here are the pictures I took of my shredder attached to the tractor and the sheared tailwheel/A frame bolts. The tail wheels do take allot of abuse over rough ground - mostly hog wallows. But you'd think they'd last more than a half a dozen hours...that's how long it took me to break the bolts after the mechanic put new ones in.

Maybe I just need to slow down. But that's why I bought the JX95...so I wouldn't have to slow down. I've been mowing in 2nd range...in 3rd gear over rougher ground and 4th gear over somewhat smoother ground.

The Rhino shredders look like they have a tougher tail wheel assembly - if I break this one again, I think I'll try one. At least if I break the tail wheel off, the A-frame won't come detached too.

 

[Farmwithjunk]

Ground speed isn't HELPING, but that mower should be able to take a bit of abuse.

Something else jumps out at me. Is the "toggle" free to move? That's the flexable link just behind where the A-frame attaches to the quick hitch, and where the struts divide and continue to the rear of the mower. There should be EASY movement there. (see picture #3) Something looks peculiar in that picture. My 297 is still sitting at the dealer, waiting for delivery when they bring a new tractor that's on order. If I'm near there any time soon, I'll try to get a picture. Make certain that toggle is allowed to move freely to let the mower and tractor flex with irregular terrain.

Also, I don't see a problem with possibly using grade 8 bolts where you're snapping the grade 5's, OTHER than the fact that may make a more expensive component the weak link in the chain of events.

Raise the hitch, back the mower up where the tail wheels are over something a foot or so tall, then lower the hitch. Does that toggle flex and allow the front of the mower to continue down with ZERO resistance? If NOT, there's your problem.

On a Woods BB840 I owned, that toggle wouldn't allow ENOUGH flex. It moved freely, but ran out of travel in some situations. I cut a 12" section out of each of the top struts and replaced it with chain. That allowed substancially more freedom of movement. Proir to that, I was bending those struts every time I ran over a sizable irregularity.

 

[chh]

Will the top pivot move? Check like Farm said, your lower bolt holes show a lot of wear but I don't see any signs of it moving up by the pivot. How much acreage are you cutting? You have enough hp to be pulling a much larger mower if you wanted. If you have a large area and rough terrain a tow type mower might be better for you situation. You could easily use a 10' pull type up to a 15' batwing. The JX 95 is 90 engine hp and 80 pto hp if I looked at the chart correctly.

 

[Robert_in_NY]

Is it just my eyes this moring or does the supports from the rear to the top of the A-frame have a different size hole then the tailwheel support and they are using one mounting point for both supports? If so the aparent lack of flex on the top link would make a shock point where the tailwheel support and toplink support come together. The slack from a small bolt going thru a larger hole will eventually shear the bolt.

I wonder if Bush Hog had a special bolt for that hole (either it came with a bushing or was two sized and when it broke the first time the mechanic just tossed a bolt that fit the small hole in it with a large washer to keep the head from going thru the larger hole.

Then again the medication I am on right now can just be making me a little crazy.

Best of luck to you.

 

[Alanray]

It's going back to the dealership for a Wood's Loader after the first of the year - I'll have them fix it again and check to see if it is flexing like it should.

Would the pull type shredders take the rough ground better? A 10' would be better for someone like myself with ADD who likes to see a difference everytime I make a turn.

 

[Robert_in_NY]

A pull type cutter follows the ground a lot better then a 3pt setup and gives you a much more even cut.

 

[firemanpat2910]

I agree it looks like the quick hitch is eliminating the front pivot point. either try it without the quick hitch or make a flexable top link out of chain or cable.

 

[chh]

Look at a 10' the next time you go by a dealer, heavy duty, not a grass shredder. They will take a lot going over rough ground. I use a 15' Rhino batwing on several hundred acres every year. This was year #5 for the current one and have had 0 problems with it so far. The wider path you cut the better it is for ADD, just ask my wife.

 

[Farmerford]

Alanray:

I may be overlooking it, but I don't see a toggle in the top link, either in front of or behind the quick hitch.

It also appears that the holes in the tabs on the mower deck are elongated to the front, which indicates that the primary stress comes from the mower dropping against the TPH. If the wheels were overstressed, wouldn't the height adjusting bolt be the first to break. It is a fulcrum in the wheel arms and the vertical force on it will be the sum of the forces on the wheel and the front pivot bolt. Furthermore, a vertical force would tend to elongate the tab holes downward.

I believe the rough ground is bouncing the mower up and down more than you think, and the downward movement is frequently caught by the TPH. The single shear strength of a 5/8" Grade 5 bolt may be only 10-15 thousand #. That mower probably weighs 2000# and the shallow angles of the arms from the a-frame to the tabs means the force on the bolts is at least doubled. I don't have my mechanics book handy, but 2000# moving several feet per second has considerable momentum, and if the movement is stopped in just a few inches the initial forces could easily approach the shear strength of the bolts.

As Robert said, the slack in the bolt holes adds to the sudden impact, as does the other slack in the top link system.

 

[Alanray]

From the 290 Series Manual:

"E. Position tailwheel frame arms inside of attaching
lugs on cutter deck (behind gearbox) as shown in
Figure 5-1. Position free ends of yokes outside of
attaching lugs and place a yoke bushing inside of
holes on yokes and a 5/8 SAE washer on the outside
of the yokes. Align holes in tailwheel frame,
lugs, yokes/bushings, and washer and connect them
using a 5/8 x 2-1/2 capscrew. Secure using a 5/8
locknut and tighten until nut is almost bottomed on
tailwheel frame, but not so tight as to prevent rotation
of tailwheel frame."

BUT, I never saw any type of "yoke bushings" on my cutter - it didn't come with any on the tail wheel assembly when I got it and the mechanic only installed bolts when they broke.

Am I reading that right - it does require bushings at those connections right?

 

[Alanray]

And attached is the parts diagram from the Bush Hog website - it also shows a bushing at that location. So now I'm assuming that the lack of bushings could cause the bolts to shear since one of the holes is bigger than the bolt causing a hammering action against the bolt...I assume thats the reason a bushing is used here.