Questions about New Holland 451 Mower

[davel8257]

I just bought a used 451 mower this weekend. I put it on the tractor and in 10 minutes was out doing some light mowing (weeds, road side grass). The sickle bar seemed to be set pretty high, so I thought I'd try to adjust it downward. The former owner said some things about the 2 arms that have slip fittings -- get them set and the heighth will be perfect.

Ok -- so, I undid the (2) 3/4" nuts and bolts on both sides, tripped the latch and tried some adjustments. I moved it way up -- the bar seemed at even steep (more upright) angle. So, I moved the grippers down on the arms back to about where they were. Now, I have a new problem...

On my Kioti, the stabilizers are attached with an eyebolt which is held in place with a large nut on the inside of the 3pt arm. That nut hits the gripper assembly on the mower. If I get one side on, I can't get the other side on - the nut hits the side of the gripper assembly. It's dark now (been working on for 2 hours!) -- I could try to post some pics tomorrow evening after work.

And with all of this up/down, jiggle that, move there. bang on this thingy ... it seems to me that I should have chosen an entirely different approach to setting the angle of the sickle bar. There's a couple lengthes of chain on the sickle bar attached to a threaded eye-bolt. If I unscrewed (lengthened) the eyebolt, my guess is that the sickle bar would lay down flatter.

Signed,
take 2 aspirin and maybe the banging in my head will stop...

 

[sweettractors]

I just bought a used 451 mower this weekend. I put it on the tractor and in 10 minutes was out doing some light mowing (weeds, road side grass). The sickle bar seemed to be set pretty high, so I thought I'd try to adjust it downward. The former owner said some things about the 2 arms that have slip fittings -- get them set and the heighth will be perfect.

Ok -- so, I undid the (2) 3/4" nuts and bolts on both sides, tripped the latch and tried some adjustments. I moved it way up -- the bar seemed at even steep (more upright) angle. So, I moved the grippers down on the arms back to about where they were. Now, I have a new problem...

On my Kioti, the stabilizers are attached with an eyebolt which is held in place with a large nut on the inside of the 3pt arm. That nut hits the gripper assembly on the mower. If I get one side on, I can't get the other side on - the nut hits the side of the gripper assembly. It's dark now (been working on for 2 hours!) -- I could try to post some pics tomorrow evening after work.

And with all of this up/down, jiggle that, move there. bang on this thingy ... it seems to me that I should have chosen an entirely different approach to setting the angle of the sickle bar. There's a couple lengthes of chain on the sickle bar attached to a threaded eye-bolt. If I unscrewed (lengthened) the eyebolt, my guess is that the sickle bar would lay down flatter.

Signed,
take 2 aspirin and maybe the banging in my head will stop...

Try putting mower back where you were not having a problem......To adjust the height you carry the mower on your 3 point lift arms, set the depth control on your tractor.......control blade angle with toplink. Ken Sweet

 

[davel8257]

I'm not 100% sure I remember where it was set initially -- that's what occured to me as I walked back into the house tonight...

I can see how the angle would be affected by the top-link. I played with that a bit.

The other 2 points that you suggest are intuitively likely, but not consistent with my real-life experience.

For instance, when I lowered the arms all the way down -- the 'runners' on the bottom of the mower were still off of the ground. It seems that the 'grippers' were holding onto the slip arms and keeping them 'up'. Thus, lowering my 3pt arms did not let the sickle bar fully settle onto the ground resulting in a higher cut than I wanted.

I'm not sure what you mean by 'depth control' on my tractor? I have the arms set in the lowest notch of the lift-arms -- this should allow my arms to get just about as low to the ground as possible.

I had a random thought about the stabilizer attachment. If I removed the stabilizer eyebolt and nut -- I'd not have a problem. If I used that eyebolt and nut and ran it through the lift-arm attachment, I'd also not have an interference problem. (I might have other problems -- like a stabilizer link that is too long and would need to be shortened to be useful.).

 

[sweettractors]

I'm not 100% sure I remember where it was set initially -- that's what occured to me as I walked back into the house tonight...

I can see how the angle would be affected by the top-link. I played with that a bit.

The other 2 points that you suggest are intuitively likely, but not consistent with my real-life experience.

For instance, when I lowered the arms all the way down -- the 'runners' on the bottom of the mower were still off of the ground. It seems that the 'grippers' were holding onto the slip arms and keeping them 'up'. Thus, lowering my 3pt arms did not let the sickle bar fully settle onto the ground resulting in a higher cut than I wanted.

I'm not sure what you mean by 'depth control' on my tractor? I have the arms set in the lowest notch of the lift-arms -- this should allow my arms to get just about as low to the ground as possible.

I had a random thought about the stabilizer attachment. If I removed the stabilizer eyebolt and nut -- I'd not have a problem. If I used that eyebolt and nut and ran it through the lift-arm attachment, I'd also not have an interference problem. (I might have other problems -- like a stabilizer link that is too long and would need to be shortened to be useful.).

Making the toplink longer raises the tips of the rock guards. If you need more....look behind the big drive pully and you will see grooves and a clamp plate.... adjust more angle here. Are you calling the sickle bar inside and outside skid shoes runners or are you referring to the 2 3/4" diameter stands under the a-frame?.....Don't try to tightly stabilize the mowers left right swing unless it is getting into your tires.....a owners manual would be very beneficial.....lots of them on ebay cheap. Ken Sweet

 

[davel8257]

Fortunately, I took a picture of the mower when I brought it home. I was able to count the notches on the arms and re-set the configuration back to the way it was when I got it. I had to line up the mower exactly centered behind the tractor and got it re-connected to the tractor.

I then drove away and began to hear 'strange' noises from the tractor. I had raised the arms to drive away. But, the top-link structure on the 451 was being forced up against the hook up on the tractor. It was only being allowed to raise a couple of inches. That was not sufficient for the drive pulley (at the hinge) to clear the ground. It was dragging in the grass.

So, I 'fixed' one issue (barely -- stabilizer arm nut barely clears the grippers on the 451), but created a new one (very limited vertical lift range).

I've taken the 451 off and moved onto another project. I'll get back to this in a few weeks when the grass grows back up and I need to do more mowing.

 

[Haydog]

Hi I'm new to the forum. I saw that someone may have a pdf for a NH 451. I just bought one and was looking for a manual.

 

[petes]

The levers and eyebolts on the U shaped stabilizer are used to switch between hook-up and mowing modes.
If the eyebolts are unhooked the mower frame can be lowered all the way to the ground (set on the 3/4" diameter parking skids) to be unhooked from the 3pt. After hooking up, raise the 3pt and engage the eyebolts/levers for transport and mowing. The mower frame will (should) be stopped at the correct height when lowered, allowing the cable to lower the cutterbar to the ground for mowing but keeping the mower frame off the ground. When everything is set correctly, the top of the rectangular horizontal tube of the frame should be 16" off the ground when lowered (eyebolts hooked). Adjust the position of the cone shaped stops on the U shaped stabilizer to get it at 16". When eyebolts are hooked and the 3pt is lifted adn lowered, the cable/spring causes the cutterbar to lift and lower while remaining parallel to the ground, (the mower frame stays at the same height), enabling it to clear obstructions or already downed grass.

 

[petes]

The levers and eyebolts on the U shaped stabilizer are used to switch between hook-up and mowing modes.
If the eyebolts are unhooked the mower frame can be lowered all the way to the ground (set on the 3/4" diameter parking skids) to be unhooked from the 3pt. After hooking up, raise the 3pt and engage the eyebolts/levers for transport and mowing. The mower frame will (should) be stopped at the correct height when lowered, allowing the cable to lower the cutterbar to the ground for mowing but keeping the mower frame off the ground. When everything is set correctly, the top of the rectangular horizontal tube of the frame should be 16" off the ground when lowered (eyebolts hooked). Adjust the position of the cone shaped stops on the U shaped stabilizer to get it at 16". When eyebolts are hooked and the 3pt is lifted adn lowered, the cable/spring causes the cutterbar to lift and lower while remaining parallel to the ground, (the mower frame stays at the same height), enabling it to clear obstructions or already downed grass.

 

[keegs]

Try putting mower back where you were not having a problem......To adjust the height you carry the mower on your 3 point lift arms, set the depth control on your tractor.......control blade angle with toplink. Ken Sweet

+1 ....

 

[BaiJiu]

Hi I'm new to the forum. I saw that someone may have a pdf for a NH 451. I just bought one and was looking for a manual.

Did you ever find a manual? I bought a NH 451 this week and can't seem to find a manual at a reasonable price. There are a few in the US but with the CDN dollar being so low, shipping and tax they are nearly $100 just too expensive for me.