Problem with IH 720 mouldboard plow stuck 'Up"

Thanks in advance for the help.

I have been trying to learn how to farm, bought a bigger tractor and some used implements, including the IH 720 plow

This unit has 4 blades, with 4 disks (one in front of each blade) and a pair of real big springs so the blades ride up over big rocks, rather than hanging up.

I spent the day plowing. (it wasn't pretty, but I'm learning)

As I was getting ready to call it a day, I noticed one plow/disk/spring assembly stuck in the up position.

So, its like I road over a real big rock and the assembly jammed in the up position.

The spring are under tension, and the sort of parallel links holding the plow assembly are as well. The heavy bar which holds the plow assembly is relatively loose. First I though maybe the assembly was stuck, despite the huge springs and heavy weight. I whacked it with a heavy hammer a few times and it didn't budge. Besides, the pivots, are all well greased and there is no real reason to believe even if they were rusted iweight.t would hold the

Now I wonder if this is intentional - i.e. there is a way to lock a plow 'up' to put it out of commission if you have a real dense soil, or something.

If this possible? If so, how do I lock/unlock?

If not, any suggestions as to what to do? It looks like a nasty dissassembly.

Thanks again

buy a manual for your impltments and you will learn the operation of them/ ood luck.

Thanks for the advice. I haven't found a manual for this implement. I did find one for my haybine, which cost $60 and told me nothing about how to use it properly. Lots of warnings & lawyer stuff though.

I am sure many questions posted could be answer by 'read the manual' but I'd really like some help.

I'm only familiar with Oliver plows, so I'm not much help there. There are however a couple manuals on ebay right now for $10 plus shipping. It'll show you how to set it up properly for your tractor, and should say if there are any tricks to reset the moldboards.

On our Oliver plows you have to back up while in the furrow to reset the spring trip bottoms. They were also available with spring auto reset bottoms that would reset themselves. There is a way to lock the moldboards up on ours to change wear parts. I would imagine that IH had a similar feature.

Donovan from Wisconsin

back up,at least it worked with our JD with trip. Good luck, if I had to buy a manual for every piece of worn out machinery on this place I would have to sell the land so I could buy books. That is why I pay for an Internet connection

(quoted from post at 03:23:10 06/07/09) back up,at least it worked with our JD with trip. Good luck, if I had to buy a manual for every piece of worn out machinery on this place I would have to sell the land so I could buy books. That is why I pay for an Internet connection

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Don & 504 - thanks for the input. I suspect my plow is 'auto reset' because a few auction listings call it that. It sounds like the 'lock up' Don mentioned.

Any suggestions as to how to lock and unlock would be appreciated.

Its 'high and dry' relative to the furrows, so I don't think backing up will help, but I'll try. Maybe I have to sit the blade on a big block of wood or something and back up/forward and see. Maybe jacking it up further will release.

As for manuals, I am a big believer in them. I threw a hissy fit at the dealer where I bought my tractor and finally got the manual today. The tractor is new: the plow is 30 or 40 years old, if I could find a manual it won't be quick, and it won't help me finish my fields ...

Thanks again

Auto reset IH plows are not supposed to remain in the tripped position. There may be tremendous pressure against whatever is binding or broken. This is NOT normal at all, I have plowed thousands of acres with IH auto reset plows and have not seen this. Use caution around this plow until you get it figured out. If that thing decides to reset while you are in the way, you will have broken bones, or be dead.

(quoted from post at 11:06:06 06/07/09) Auto reset IH plows are not supposed to remain in the tripped position. There may be tremendous pressure against whatever is binding or broken. This is NOT normal at all, I have plowed thousands of acres with IH auto reset plows and have not seen this. Use caution around this plow until you get it figured out. If that thing decides to reset while you are in the way, you will have broken bones, or be dead.

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Thanks for the warning - I'l be very careful.

The thing I should mention is that the plow is 'up' but exactly parallel to the other blades. Its almost like its raised. I haven't seen what happens when you hit a rock, except from the cab, but the impression I had is that it sort of lifts from the back, whereas this one looks like al the other blades, its just a foot or so higher up (and the springs are stretched).

One reasn I sort of suspect there is a catch is how 'perfect' it broke ...

I used a 710 auto-reset (6-20") last week for a neighbor. What yours has done would scare the h3ll outa me! Stand behind it always while working on it and don't trust it. There may have been a rock jump up into the mechanism jamming it. As a side note- to indicate the power behind those reset springs I have a old 555h John Deere 3-14" plow and the trip rollers are set to trip at around 4500lbs from the factory. The plow isn't auto-reset but I hope you get the point. That 720 bottom is designed to dig back into the ground and reset while you are moving. That's going to take a LOT of pressure. I'm pretty sure you don't want to unscrew the tension bolts either because they probably aren't long enough to take out with the spring compressed. You have a very dangerous situation there. Sorry I couldn't be of more help. Good Luck! ...Randy

I"ve had a 720 since 1980. The trip assembly is designed for it to trip either of two ways- it can stay parallel to the ground and ride straight up over shallow rocks- that is what yours has done...or it can trip in the conventional manner where the point catches on a big rock and the bottom flips up and over the rock. In your position, the springs should be tipped forward. DO NOT WORK BEHIND THE BOTTOM! I think you could safely release tension by unscrewing the two spring bolts from the front side of the frame. I would stand on a box on the front side of the frame and carefully reach over, if I could not attach a chain to the standard, anchor it, and pull ahead. You do not adjust trip tension by those two bolts- there is a small lug bolted within the trip mechanism that does that. Both springs need to be tightened down (bottomed out) upon reassembly. I would look for some worn, bent, or missing linkage parts so this does not happen again.

(quoted from post at 01:23:26 06/08/09) I"ve had a 720 since 1980. The trip assembly is designed for it to trip either of two ways- it can stay parallel to the ground and ride straight up over shallow rocks- that is what yours has done...or it can trip in the conventional manner where the point catches on a big rock and the bottom flips up and over the rock. In your position, the springs should be tipped forward. DO NOT WORK BEHIND THE BOTTOM! I think you could safely release tension by unscrewing the two spring bolts from the front side of the frame. I would stand on a box on the front side of the frame and carefully reach over, if I could not attach a chain to the standard, anchor it, and pull ahead. You do not adjust trip tension by those two bolts- there is a small lug bolted within the trip mechanism that does that. Both springs need to be tightened down (bottomed out) upon reassembly. I would look for some worn, bent, or missing linkage parts so this does not happen again.

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Based on everybody's comments I sort of repaired the plow.

I put 2 pieces of 6x6 under the blade so there was only about 1/2" gap.

Then I relieved the spring tension (nice to have an impact driver)

The spring assembly fell away, and the blade was still stuck 'up'

I was able to wiggle most of the components, except a "main spar" which hinges on a 2" or so diameter pin.

So I removed most of the pieces and the spar still wouldn't budge

When I got the plow, I noticed one of the disks was damaged so I had removed one blade + disk, so I was operating only 3 blades (2 with the one stuck up).

So I decided to rebuild the plow with the damaged disk using the parts of the stuck one.

This was relatively easy to do as I was able to use the loader of my small tractor as a crane.

Long story short, after a couple hours or so, I am back in business. Now that the unit has been removed, it is obvious the problem is with the great big hinge pin on the main spar.

I'll try remove it with heat and or a hydraulic press or I may end just cutting the plow down to 3 sections. It looks pretty easy to do and I have enough trouble plowing as is. My tractor has plenty horsepower, but even with ballasted tired I can't get enough traction most times


Thanks again, everybody.