John Deere #38 sickle mower

[papsygoobs]

My John Deere #38 sickle mower repeatedly breaks the metal straps connecting the pitman to the drive shaft. Has anyone else had this problem and, if so, did you find a solution? Thanks.

 

[wore out]

My John Deere #38 sickle mower repeatedly breaks the metal straps connecting the pitman to the drive shaft. Has anyone else had this problem and, if so, did you find a solution? Thanks.

Photo of what's breaking, please.

 

[matthies]

So it is breaking on the flywheel end or the ball end? Thin metal, or thicker cast? If the cast is breaking you might be overtightening the bolts, would be better to use a lock nut or double nutting them. If you are trying to cut small bushes/brush that could also be your problem.

 

[Loosehandle]

My John Deere #38 sickle mower repeatedly breaks the metal straps connecting the pitman to the drive shaft. Has anyone else had this problem and, if so, did you find a solution? Thanks.

What condition are your sickle and guards in? What are you mowing?

 

[papsygoobs]

What condition are your sickle and guards in? What are you mowing?

Sickle and guards are not new. But they appear to be in decent shape. I am mowing blue gramma and brome grass.

 

[papsygoobs]

So it is breaking on the flywheel end or the ball end? Thin metal, or thicker cast? If the cast is breaking you might be overtightening the bolts, would be better to use a lock nut or double nutting them. If you are trying to cut small bushes/brush that could also be your problem.

They are breaking on the flywheel end. I will try double nutting. Thanks.

 

[papsygoobs]

Photo of what's breaking, please.

 

[wore out]

Sickle and guards are not new. But they appear to be in decent shape. I am mowing blue gramma and brome grass.

"Sickle and guards are not new. But they appear to be in decent shape"

Not to be snarky, but are you experienced with sickle mowers and know how the parts should look?

The knife sections need to be SHARP and not worn away, and the hold down clips need to be set up so that the knife sections run CLOSE to the ledger plates or guards, so they work like a scissors and would literally shear paper.

Also, the knife needs to be "in register", if it NOT the mower will literally be tearing off the material rather than shearing it. The Operator's Manual will tell about this and how to correct it if it's "off". Are you using an OEM pitman stick or a home-made one, (exact length between mounting holes end-to-end affects "register")?

Also, there was a drive sheave option to run the flywheel at 850 or 950 RPM's with the higher speed favored for cutting extra tough material.

 

[1939farmall]

I’m running John Deere #37 and #39 mowers. The 37, 38, and 39 and the same basic mower just mounted differently. 37 is a trailer type, 38 has the tail wheel, and 39 is mounted.

It’s hard to tell in the picture but it looks like the pitman is made of pipe. I know a lot of people have done that but I believe that should be made of wood. Both mine are. They are getting hard to come by here so I make my own out of hickory. That pitman arm should break before the cast yoke on the flywheel does.

Ideally non of it breaks of course! But this is telling me something is out of adjustment. As stated above it is crucial the knives be “ in register”, or in time. Everything wore out said is spot on. I think I would be rotating the PTO shaft by hand, disconnected from the tractor and see if the is a hard spot in the knives travel. If something is out of adjustment you will keep breaking things.

Also I would suggest getting a manual a reading up. I’m not sure if one is available on our site here, but if not you can get one from these guys. https://peacefulcreek.com/?srsltid=AfmBOopkaVTzjghjZmuDvvbT8d0ew8BITI12y3ggJqTey1AiZ1mGHYdf

Hope that helps and please update us with what you find.

 

[wore out]

I’m running John Deere #37 and #39 mowers. The 37, 38, and 39 and the same basic mower just mounted differently. 37 is a trailer type, 38 has the tail wheel, and 39 is mounted.

It’s hard to tell in the picture but it looks like the pitman is made of pipe. I know a lot of people have done that but I believe that should be made of wood. Both mine are. They are getting hard to come by here so I make my own out of hickory. That pitman arm should break before the cast yoke on the flywheel does.

Ideally non of it breaks of course! But this is telling me something is out of adjustment. As stated above it is crucial the knives be “ in register”, or in time. Everything wore out said is spot on. I think I would be rotating the PTO shaft by hand, disconnected from the tractor and see if the is a hard spot in the knives travel. If something is out of adjustment you will keep breaking things.

Also I would suggest getting a manual a reading up. I’m not sure if one is available on our site here, but if not you can get one from these guys. https://peacefulcreek.com/?srsltid=AfmBOopkaVTzjghjZmuDvvbT8d0ew8BITI12y3ggJqTey1AiZ1mGHYdf

Hope that helps and please update us with what you find.

He can download a manual for FREE at https://techpubs.deere.com/en-us/Search/Equipment.

Go there and enter "E39954" in the search box, then click on the download arrow.

 

[papsygoobs]

"Sickle and guards are not new. But they appear to be in decent shape"

Not to be snarky, but are you experienced with sickle mowers and know how the parts should look?

The knife sections need to be SHARP and not worn away, and the hold down clips need to be set up so that the knife sections run CLOSE to the ledger plates or guards, so they work like a scissors and would literally shear paper.

Also, the knife needs to be "in register", if it NOT the mower will literally be tearing off the material rather than shearing it. The Operator's Manual will tell about this and how to correct it if it's "off". Are you using an OEM pitman stick or a home-made one, (exact length between mounting holes end-to-end affects "register")?

Also, there was a drive sheave option to run the flywheel at 850 or 950 RPM's with the higher speed favored for cutting extra tough material.

This is a much overdue report and word of appreciation. But as the saying goes, "Better late than never". I tried all of the suggestions, plus 1 to achieve success. That is, I installed all new knives. (I tried using the newer style bolts vs rivets and will never make that mistake again.), checked the register and replaced the heavy steal pitman with a new wood pitman. But for good measure and out of fear, I reduced the ground speed of my tractor. I managed to cut the entire 2025 crop (only 8 acres mind you) without incident. Thanks to all of you for the advice and tips.