Brush Hog Top Link Question

[grandpa_e]

I just got a brush hog, a Modern Ag 4' Competitor series for use on my Kubota B2320. I ran a brush hog when I was younger, but never paid attention to the top link. The hog came with a swivel link at the top. I assume this allows the tailwheel to come up when you go through a dip. My problem is that the B2320 has a quarter inch control for the 3 point hitch, not position control. Would it be ok to use a solid top link and pin it directly to the brush hog without the swivel? Then I could leave the 3pt full down which would float. That seems to me like it would work better and still allow the hog to rise and fall with the contours of the property. Any expert advice?

 

[LD1]

The main issue is when you back up and the tail wheel tries to go uphill. All 3PH float in the downward position. But if the tailwheel wants to raise up the hill and not the front, it tends to want to "rotate" about the lower pins instead of float like you might think. This puts a lot of stress on the TL and BH frame.

I would personally leave it alone. But some bushhogs that use a rigid TL mount have a chain that connects the top of the A-frame doen to the tail wheel and the a-frame pivots at the bottom where it attaches to the BH.

The ones that are TRULY a rigid setup, most guys use a chain in place of the TL to allow for the movement.

 

[RoyJackson]

That bracket allows the front of the rotary cutter (actual name of what you're referring to as "bush hog") to float.
I don't have a Kubota, so I'm not familiar with that quarter inch control but doesn't the rockshaft lever have a movable stop of some sort?
Anyway, I'm with LD1, I'd leave it alone.
However, if you want to try a "rigid" set up, just shorten the top link until the tail wheel starts to lift, then lengthen just enough for the tail wheel to rest on the ground That will simulate a rigid set up.

 

[TripleR]

Quarter inching valve 3-point has no impact on the use of the swivel, I have a BX2660 and L5030 and keep the swivel on both cutters. As mentioned, it will put a lot of strain on backing up a steep incline.

As mentioned, some use chains which will do essentially the same thing.

I would leave it as is, but just my.:2cents:

Just as an FYI, KUGator uses chains hooked to the deck and tractor to keep his deck height consistent as the non position control 3-point will drop down and you have to keep bumping it back up.

 

[LD1]

Just as an FYI, KUGator uses chains hooked to the deck and tractor to keep his deck height consistent as the non position control 3-point will drop down and you have to keep bumping it back up.

My JD261 finish mower is set-up this very same way. It is only a 2-guage wheel version. So it doesnt have wheels in the front, thus the chains to hold it up.

 

[beppington]

I don't think what you're describing will work. The 3PH likes to float up when pushed directly up from a point at or near the 3PH itself. If you push up from a point 4 or 5 feet back away from it, such as at the tail wheel, I suspect the 3PH won't float up; Rather it would just jam up. I could be wrong, but if you try it I'd try it at very slow speed first, & while turned around watching it. Very slowly back into a ditch & watch to see if the 3PH floats up. I don't think it will.

The rotary cutter I use has a slotted top link, but I sure wish it had a swivel like yours, so I'd never have to even think about the RC's tail coming up too high & jamming against the top link. Even with this slot, a severe ditch can jam it. No damage so far, but it can't be good for it or the tractor. Something's gotta give

Here's a pic:

 

[LD1]

I don't think what you're describing will work. The 3PH likes to float up when pushed directly up from a point at or near the 3PH itself. If you push up from a point 4 or 5 feet back away from it, such as at the tail wheel, I suspect the 3PH won't float up; Rather it would just jam up. I could be wrong, but if you try it I'd try it at very slow speed first, & while turned around watching it. Very slowly back into a ditch & watch to see if the 3PH floats up. I don't think it will.

The rotary cutter I use has a slotted top link, but I sure wish it had a swivel like yours, so I'd never have to even think about the RC's tail coming up too high & jamming against the top link. Even with this slot, a severe ditch can jam it. No damage so far, but it can't be good for it or the tractor. Something's gotta give

Here's a pic:

Jam up is exactally what WILL happen most of the time. That is why I see a lot of cutters with a rigid setup (that someone doesnt use a chain for the TL) have the angled braces that go down toward the tailwheel all bent out of shape

 

[greg_g]

The "swivel" device on the rotary cutter (RC) is called a floating toplink bracket (FTB). If you've got the U-type, the correct use is
(a) pin the FTB to your tractor's adjustable toplink,
(b) tighten the tractor toplink as short as it will go (so the FTB is pointing at the tractor) to lift the RC for transport,
(c) extend the tractor toplink until the FTB is at the 6:00 position (pointing at the ground) for mowing.
(d) when you're done mowing, repeat step (b)
With the FTB pointing at the ground, it will swing through an arc as the front of the mower follows the terrain, thus keeping the RC tailwheel on the ground

There are other than U-type RTBs though. I've used them all. If you have another type, describe it. I'll run you through the settings if necessary

//greg//

 

[grandpa_e]

Thanks to everyone for all the info. greg_g, mine is the U shaped bracket like you described. They way I had it was not too far from what you described. I didn't have it at 6:00 position. I will play with it some more and see how it does. I'm thinking the chains TripleR mentioned may help as well.

 

[beppington]

Never experienced it myself, but I've heard that the chains setup can allow the rotary cutter to come waaaaay up to about vertical(?) & about scare the livin' daylights out of ya ... Probably wouldn't happen too often, if ever, so maybe no big deal.

However, if it does I wonder if there's a chance that the chains themselves could actually get caught in the cutter? :shocked:

 

[RoyJackson]

Never experienced it myself, but I've heard that the chains setup can allow the rotary cutter to come waaaaay up to about vertical(?) & about scare the livin' daylights out of ya ... Probably wouldn't happen to often, if ever, so maybe no big deal.

However, if it does I wonder if there's a chance that the chains themselves could actually get caught in the cutter? :shocked:

The real problem is if the cutter came that high, you might have the tail wheel bracket buried in your back or head.
I know some guys do use a chain for the toplink...more power to them. But for me, that toplink provides a limiting factor if the cutter jumps.
I doubt if the chains would be long enough to tangle in the blades though.

 

[LD1]

However, if it does I wonder if there's a chance that the chains themselves could actually get caught in the cutter? :shocked:

If a chain is used in place of a TL, it should be NO longer than the TL was. If that is the case, there is NO chance of it getting caught.

Same for the ones that have the chain from the A-fram down to the tailwheel. Only way it can get caught is if it breaks

 

[TripleR]

This is from the manual on my Land Pride RCR2672


Refer to Figure 2-2:
1. Lower cutter deck to the nominal cutting height.
2. Adjust length of tractor痴 3-point top center link such
that the top and bottom hitch pins are aligned
vertically with each other. The pivot hitch should be
at about a 45 degree angle when adjusted correctly.
3. Lock center link in this position.

 

[RoyJackson]

This is from the manual on my Land Pride RCR2672


Refer to Figure 2-2...

It is important to read the manuals.
Per the Land Pride Manual (for an RFM, actually), the hole in the FTB is to be directly above the lower link pins (pictorially, this appears to be the 45 deg angle Triple R refers to).

 

[greg_g]

I'm thinking the chains

Using a chain in place of a toplink is an accident just waiting to happen. I strongly recommend against the practice. Chains between the A-frame and the rear of the mower aren't much better. The purpose of the metal straps is to give the A-frame some flex, while stopping the deck from flipping up and hitting you in the back of the head. Chains instead of straps will in fact give more flex, but do nothing to stop a flipping deck

//greg//

 

[LD1]

Using a chain in place of a toplink is an accident just waiting to happen. I strongly recommend against the practice. Chains between the A-frame and the rear of the mower aren't much better. The purpose of the metal straps is to give the A-frame some flex, while stopping the deck from flipping up and hitting you in the back of the head. Chains instead of straps will in fact give more flex, but do nothing to stop a flipping deck

//greg//

How is the deck going to magically flip up and hit you in the head??? Are you driving upside down or something???:confused2:

 

[beppington]

How is the deck going to magically flip up and hit you in the head??? Are you driving upside down or something???:confused2:

I dunno if it would go quite far enough to hit someone in the head(?), but it could certainly come way up by: Back your rotary cutter into some brush, maybe there's a log in there that the tail wheel goes up & over, then the sides of the deck ride on the log as you continue backing - The further back you go the higher the tail end of the deck rises. I haven't had that happen, but that's the way my dad explained it to me ... when he found out the upper bolt securing the diagonals had come out of the cutter I posted the pick of above.