# New Holland 617 Disc Mower Timing



## CRE10 (Sep 28, 2013)

How do I adjust the timing? My first two discs closest to the tractor are hitting blades. Someone said to adjust the first one off a vent hole and work your way down the line?

I don't think anything is torn up. I guess if it gets out of timing again then I know I have some issues.


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## Circle MC Farms LLC (Jul 22, 2011)

I'm not an expert but from looking at those pictures all of them are lined up except that one so what I would do is unbolt that last disc and line it up with the others and hope for the best. Has it always done that or did it develop while you were cutting? If it has rock protector shear hubs then it may have sheared that particular hub.


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## bluefarmer (Oct 10, 2010)

Agree with farmboy


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## CRE10 (Sep 28, 2013)

It doesn't work that way. That pic is deceiving. If I turn the turtle it makes them hit, not just the blades. Oh well, paying a NH guy to come in the morning to do it. That first disc is just off a few degrees.


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## Colby (Mar 5, 2012)

Take off the 4 3/4" bolts on top of hat, take hay off and there is a bolt that the hub is on take that off and rotate the hub which way it needs to go. Takes about 5 min, faster if you have impacts. 
What happened? Bearing failure?


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## mike10 (May 29, 2011)

First you need to determine if it is the first or the second disc which is out of time. Turn the discs so they are 90 degrees to each other and find the one which is not. As Colby stated remove the disc and the drive hub. I would go one step further though and remove the four bolts which hold the top cap to the module. Remove the top cap and with the cap removed you can see if there are any teeth missing from the gears. It only takes a minute and a little silicone for some peace of mind. During assy of the drive hub do not use an impact to install a new center bolt. Don't reuse the bolt you took out. Torque to 135 ft/lbs.

Chances are you have twisted the drive shaft between the two modules. With the discs 90 degrees to each other place the drive hub on the splined shaft so one of the bolt holes in the hub is aligned with the breather. Before you install the center bolt place the disc on the hub and check if the knives have @ the same clearance when they cross in front of the cutterbar and in back of the cutterbar. If the distance is not equal then remove the disc and lift the drive hub off the shaft. There are only four positions the hub can go on and they are where the holes in the hub are over the breather. This will give you a finer adjustment of the timing then just jumping one spline on the shaft.


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## CRE10 (Sep 28, 2013)

Thank you.

The first disc is the one slightly off. All of the others are at 90 degrees.

I took the top off and the disc. The hub has a star type bolt that needs a socket I do not have to get it off. It looks like a female torx? Anyone know what size?

I assume once that is off then timing it is pretty easy.

I hit a galvanized wire hog panel that had been buries for who knows how many years.


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## discbinedr (Mar 4, 2013)

12 point socket is what you need. 5/8" or 11/16" I think. Great advice from mike10. You definitely have some damage somewhere if your discs were aligned and now aren't after you hit something.


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## discbinedr (Mar 4, 2013)

Farmboy555 said:


> I'm not an expert but from looking at those pictures all of them are lined up except that one so what I would do is unbolt that last disc and line it up with the others and hope for the best. Has it always done that or did it develop while you were cutting? If it has rock protector shear hubs then it may have sheared that particular hub.


The best would not happen. The reason that turtle is in a different position is because it rotates in the same direction as the adjacent one. If he did as you suggest those two would collide.


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## Tx Jim (Jun 30, 2014)

Ditto what mike10 stated.


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## Tx Jim (Jun 30, 2014)

CRE10 said:


> The hub has a star type bolt that needs a socket I do not have to get it off. It looks like a female torx? Anyone know what size?


Here's the NH bolt spec's


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## mike10 (May 29, 2011)

It takes a regular 5/8" 12 pt socket which I am sure you have. Since you hit something I definitely would take the top cap off also


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## CRE10 (Sep 28, 2013)

mike10 said:


> It takes a regular 5/8" 12 pt socket which I am sure you have. Since you hit something I definitely would take the top cap off also


Ahh I'm an idiot. I just had my 6 point impacts with me in the field. Thanks for the help and not calling me a moron 

I will let you guys know how it turns out.


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## CRE10 (Sep 28, 2013)

mike10 said:


> First you need to determine if it is the first or the second disc which is out of time. Turn the discs so they are 90 degrees to each other and find the one which is not. As Colby stated remove the disc and the drive hub. I would go one step further though and remove the four bolts which hold the top cap to the module. Remove the top cap and with the cap removed you can see if there are any teeth missing from the gears. It only takes a minute and a little silicone for some peace of mind. During assy of the drive hub do not use an impact to install a new center bolt. Don't reuse the bolt you took out. Torque to 135 ft/lbs.
> 
> Chances are you have twisted the drive shaft between the two modules. With the discs 90 degrees to each other place the drive hub on the splined shaft so one of the bolt holes in the hub is aligned with the breather. Before you install the center bolt place the disc on the hub and check if the knives have @ the same clearance when they cross in front of the cutterbar and in back of the cutterbar. If the distance is not equal then remove the disc and lift the drive hub off the shaft. There are only four positions the hub can go on and they are where the holes in the hub are over the breather. This will give you a finer adjustment of the timing then just jumping one spline on the shaft.


Dang man you're good! I opened it all up. It was super easy once I saw it all versus trying to visualize in person. It's timed up now and seems to be good to go. If it jumps again then I know I got problems, but it looked good inside the disc.

For those of you mowing rough shit, you can get a shear hub that will shear the hub before it gets into the gears into the disc. My dealer said it was around $130 for 2 of them. It might be cheap insurance for some of you custom guys doing new fields.


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## Colby (Mar 5, 2012)

CRE10 said:


> Dang man you're good! I opened it all up. It was super easy once I saw it all versus trying to visualize in person. It's timed up now and seems to be good to go. If it jumps again then I know I got problems, but it looked good inside the disc.
> 
> For those of you mowing rough shit, you can get a shear hub that will shear the hub before it gets into the gears into the disc. My dealer said it was around $130 for 2 of them. It might be cheap insurance for some of you custom guys doing new fields.


Yep, it's on the mow max bars, supposedly you can fix it for under 60 bucks


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## flame7749 (Aug 29, 2014)

Hey, CRE10, did the advise from mike10 work for you? Seems like he is the only one on this thread that knows what he's talking about. I have spent more than $2000 on my 617 and the blades still hit. I already tried a bunch of stuff already and can't get this from hitting. I had to take the 1st two blades off and mow with out them to get my mowing done (a pain in the a). Let me know if you got yours working and how please.

Thank you very much.


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## mike10 (May 29, 2011)

1. Be sure you are using the right NH blades and the blade nuts are not worn.

2. Put new blades on the first two discs and position them so they are straight out.

3. Grab the FIRST disc, only the first disc, and rotate it in the direction it turns. Watch as the blades from the first and second disc pass each other at the front of the cutter bar and note the clearence. Continue to rotate the first disc until the blades cross again on the back side of the cutterbar and note that clearence. You want the clearence in front to be as close as possible to the clearence in back of the bar.

4. If not the same or close then follow the information earlier in this post.

The reason you only turn the first disc is so all the free play is taken up in the direction the discs rotate. If the splines are worn enough on the drive shaft or pinion gears the clearences will be significanlty different when turning any other of the discs. Idealy you would use the drive pulley on the gearbox, but that is a hassel and unless you have excessive backlash between the top cap gear and the pinion gear in the first module you should do just fine by turning the first disc.


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## CRE10 (Sep 28, 2013)

Knows his stuff.


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## Tx Jim (Jun 30, 2014)

flame7749 said:


> Hey, CRE10, did the advise from mike10 work for you? Seems like he is the only one on this thread that knows what he's talking about.


Evidently you overlooked my post where I stated "ditto to what Mike stated". Oh well at least CRE10 repaired his cutterbar timing problem without paying a service call & labor.


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## ARD Farm (Jul 12, 2012)

CRE10 said:


> Dang man you're good! I opened it all up. It was super easy once I saw it all versus trying to visualize in person. It's timed up now and seems to be good to go. If it jumps again then I know I got problems, but it looked good inside the disc.
> 
> For those of you mowing rough shit, you can get a shear hub that will shear the hub before it gets into the gears into the disc. My dealer said it was around $130 for 2 of them.* It might be cheap insurance for some of you custom guys doing new fields.*


Exactly why I keep my MoCo around. Sickle bars and trash=less issues. I never mow uncharted territory with my disc machine the first time,


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## Snakeoil (Jun 30, 2019)

Hi,

I'm a new member here and actually joined to help a friend who is a farmer. I'm not.

I'm resurrecting this old thread in hopes it may apply to my friend's New Holland H7220.

His relatively new NH 7220 mower goes out of time while he his haying. He took it back to the dealer the first time and it cost him $1500 to have it put back into time. He said they had to replace the torsion bars.

Reading this thread, I'm wondering if the twisting of the drive shafts is what is happening to his 7220. Also wondering if the correction of repositioning the cutter to be back in time even with a twisted shaft will work on his machine.

I did a search for info on H7220 timing here and found nothing.

Also while searching on the web, I found info on new shock hubs for these types of NH mowers that fail rather than the shaft twisting or gears breaking when an obstruction is hit. Is this an option for his 7220. I'm sure he'd rather spend a few bucks (I believe they are about $60 each) and a little time replacing a hub versus giving the dealer another $1500.

Thanks for any help you can provide.

Rob


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## mike10 (May 29, 2011)

Shock hubs are standard equipment on that mower. The first module does not have a shock hub since the first module drives the rest of the bar. Evidently the first failure was caused by the rear tie bolt breaking at the first module allowing the cutterbar to separate partially. Take a close look at the rear tie bolt at the first module to see if the tie bolt has failed again. If the tie bolt is in place, then he probably sheared the shock hub on the disc out of time.


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## Troy Farmer (Jul 31, 2011)

I've been down this road with a 7220 and the rear tie bolt breaking. Listen to mike 10 and do exactly as he says. If the dealer keeps putting a factory tie bolt and doesn't add some spacer washers it will continue to break.  My dealer wouldn't listen to me and I continued to have problems. I now run a 630 JD MoCo.


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## Snakeoil (Jun 30, 2019)

Thanks guys. I believe it was the first (drive module) that was out of time. Dave told me last night that he is about done with NH equipment in general. He bought a round bailer that kept throwing drive chains. I looked at it and the supporting steel for all the drive parts was severely distorted. And it was made that way. None of the sprockets were in alignment. He finally gave up and traded it in on a different bailer. This mower is strike 2 for NH with Dave.

But the tip about spacers may very well solve his problem. He is not hitting rocks. This is a well used hayfield. But as you know, fields are not golf-course flat so he does hit dirt on occasion.

Also appreciate the info on the shock pro hubs being stock. I did pull up a part list last night and saw that they were part of the machine. But Dave's is about 5 years old and I thought that perhaps his was made before they were introduced.


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## mike10 (May 29, 2011)

Does he not have any dealer support, or is he buying his equipment farther off and ignoring his local dealer until a problem arises? I did not see anything in your post that could not or can not be repaired. The repair I came up with for the tie bolts is not in any book, but I did notice at one time the photos I sent to NH on my fix were shown on the technical support site.


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## Snakeoil (Jun 30, 2019)

He uses the local dealer which is only a few miles down the road from him. That is the dealer that charged him $1500 to fix it the first time. It is also where he bought it new. He tells me that the dealer is very frustrating. Says that you can never get any info out of them. He asked if he was doing something wrong or if there was a way to prevent the problem and they just shrug their shoulders.


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