What would do this to a brush cutter?

[ArmsOutWide]

I have a Rhino 172 brush cutter with 4 hours of use on it (bought it new, with the tractor).

It is pulled by a Kubota L3400-HST and an inexperienced operator (me).

I assumed that the cutter was in good shape when it was delivered (a possible mistake), and after it's first use (1 1/2 hours) I noticed that it had some peeling paint where the a-frame braces bent in. The peeling paint annoyed me, but since it was on an ancillary part, I chose not to let bother me much. After all, if I use the cutter long enough, I'll be touching up the paint all over the place at some point anyway.

It wasn't until the next time out with the mower, after a look through the owners/parts manuals, that I realized that A) "Hey, those parts are bending the same direction." and then B) "Hey, those parts shouldn't be bent at all!".

Anyway, I've sent some pictures in to the dealer, and talked with him on the phone. It's no biggie, and they will replace the parts (I'll just pick them up and install them myself when I have the chance) but I do have some questions for those of you out here on TBN.

After taking a look at the attached pictures ...

1) Have you seen this happen before?
2) If so, then what caused it?

If it's the dealer's mistake (assembling or loading/unloading maybe?), then great. Everything is fixed with the replacement braces and it's back to mowing come spring.

If it's my mistake, then I need to know what the heck I did so that I don't do it again (I actually used it rather gently in that first 1 1/2 hours as I was getting used to using the tractor, etc).

If it is a defect on Rhino's part, then I want them to send me some stronger braces!

Thanks in advance for the feedback / help.

 

[RobS]

Hey, those braces resemble the ones on my JD cutter! In my case, it was due to the rear of the cutter raising up high enough to overcome the slack I had in the top link. Mostly from backing into a rise like the opposite side of a ditch. Assuming yours is from a similar activity, you really don't want stronger braces as then something more expensive may bend or break. Some people replace the top link with a chain to let it flex completely.

That's my guess anyway. Do you remember backing into a rise of any sort?

 

[Farmwithjunk]

In all likelyhood, RobS nailed the cause.

Just about all of todays mid-duty mowers are configured like that. (I've trashed a set on a Woods mower) Replacing those struts with chain is a good way to add more flexability. A fair number of folks will be concerned with chains though. The thinking is, there needs to be something limiting travel to prevent the mower from "flipping" up on the operator. (I'd have to see that to believe it) A good way to keep all parties satisfied would be to cut a 10" to 12" section out of those struts and replace it with chain. That would give a LOT more flex, and yet provide a limit to how far the mower could raise.

OR.... Make the entire length of the strut from chain, then run it through a length of pipe about 2/3rds the length of the original strut. Same end result.

 

[RobS]

One more consideration as I ponder this more. Do you have slack in your top link at all? With the mower on level ground and in mowing position, you should have quite a bit of slack. It's hard to describe how much as each mower seems to have a different set up to accomodate the slack. Yours looks like it has a swinging top link. You need the slack to allow the mower/tractor to bend when going over uneven ground but even with some slack you'll bend things if the back of the mower tries to raise up too high.

 

[SnowRidge]

Looks like you don't have your top link adjusted properly, and you ran out of slack when you backed into something. Slack check chains or links may be contributing to the problem by allowing the cutter to swing too far to either side.

 

[ArmsOutWide]

Do you remember backing into a rise of any sort?

I didn't do any major backing up in that first 1 1/2 hours. Especially not into a rise/tree/giant rock etc. In fact, any real backing up would have been just to re-position the tractor for another forward run of grass mowing.

Since that point, I've done more backing up and backing into stands of grass and such, but haven't made any abnormal contact of note.

I could see it maybe happening when I was crossing a shallow drainage ditch/culvert. But I had the 3pt all the way up then, and was moving forward, not back.

Given the description of the likely cause, I can most readily see it happening when the delivery guy was unloading the tractor (with the brush cutter attached to the 3pt). I remember cringing as he backed the thing down the ramp, and the mower was at one point "flat" while the tractor was still angling down the ramp. It just didn't look "natural", although I didn't think about it being a "metal-bending" problem at the time.

 

[SnowRidge]

When you have it hooked up, how is the U link positioned?

 

[Farmwithjunk]

I didn't do any major backing up in that first 1 1/2 hours. Especially not into a rise/tree/giant rock etc. In fact, any real backing up would have been just to re-position the tractor for another forward run of grass mowing.

Since that point, I've done more backing up and backing into stands of grass and such, but haven't made any abnormal contact of note.

I could see it maybe happening when I was crossing a shallow drainage ditch/culvert. But I had the 3pt all the way up then, and was moving forward, not back.

Given the description of the likely cause, I can most readily see it happening when the delivery guy was unloading the tractor (with the brush cutter attached to the 3pt). I remember cringing as he backed the thing down the ramp, and the mower was at one point "flat" while the tractor was still angling down the ramp. It just didn't look "natural", although I didn't think about it being a "metal-bending" problem at the time.

The situation you described with the dealer delivering/unloading the mower and tractor is a VERY good way to bend the struts.

Once those light gauge metal struts get bent and have a weak spot, often times they bend more freely than the "toggle" where they're meant to flex.

I wouldn't jump to blame Rhino. This is a common situation with a lot of brands. However, if Rhino and/or the dealer is willing to take up the cause of replacing them, I'd just "play dumb" and let them do just that.

 

[ArmsOutWide]

When you have it hooked up, how is the U link positioned?

I've only had it hooked up once, and that was done at the dealership by someone else. Right now it is completely unattached (fall mowing is done, and the BB is on for dirt work), so I don't know exactly how it was attached to begin with.

That's not much help, but my turnaround question would be how should I attach/position it (to make sure I put it on right when I'm the one doing it)?

 

[texasjohn]

I'd focus on the U link and where the bent arms are attached. Seems to me that this area should provide a flexible link when connected to the tractor so that when the rear of the cutter gets upward pressure, for whatever reason, there will be flex and give before the supports bend. I am no expert, but my cutter has a spot that flexes when serious pressure is placed on the rear of the cutter and no bending happens.

My net... make sure that the arms are attached properly and top link is correctly placed... you shouldn't have to resort to chains to solve this problem, IMHO.