Question about a number 5 JD mower

Dr. Bert · Jun 11, 2018

While mowing today the crank wheel came off the drive shaft. The key was lost, so don;t know if it was damaged and was the cause or not.Haven;t torn the mower down yet, but can't find what broke off pr came loose to allow the wheel to move. Question-- what holds the wheel to the shaft? Does the key fit tight enough to hold everything in place? It does not appear that anything broke off the end of the shaft--ie-- a threaded portion and a nut. I've mowed with these mowers for years, but other than greasing the Pittman, I never paid much attention to how the wheel is attached. Any information or advise about how to repair the mower would be appreciated. Thank you. Dr. Bert Email is open.

David from Kansas · Jun 11, 2018

Been a long time since I have taken one off, but I think the key holds the crank wheel on the shaft. I remember I had one once that was exceptionally tight. You can look it up on jdparts.deere.com

Bob · Jun 11, 2018

Ha ha, that's a first on here, there's been all sorts of posts from guys that can't the danged crankwheel off to replace the oil/grease seal, and then yours goes and falls off on it's own!

The key and a bit of a snug fit are all that keeps the crankwheel in place.
Link to parts catalog .pdf format

ET · Jun 12, 2018

Be sure to put a new oil seal in the chain case while the flywheel is off.

Destroked 450 · Jun 12, 2018

Dad bought a #5 mower back in the 50's, we used it to do all of our mowing up until the 80's, never had the flywheel off.

Bob: Thanks for listing the parts book, that brought back good memories of that old mower.

We still have the Guard and Knife Repair Block, it was a real handy tool when replacing sections and ledger plates

Dr. Bert · Jun 12, 2018

A big Thank You to all that responded!!! My question has been answered and and the seal replacement was something I had not considered. Now, time to order parts. Dr. Bert

Hayfarmer · Jun 12, 2018

As I remember it is a tapered key with a hook on the outer end so, theoretically, you can pry it out. I have had some luck removing the flywheel by taping it in a bit to losten up the key. There is no penitrant that will help losten the flywheel other than hay dust. You can fight it for hours but take it to the field and use it, the more you need it the better, and it will losten and fall off immediately, in tall grass where you can't find the key. Ask me how I know this.

Bob · Jun 12, 2018

(quoted from post at 11:33:46 06/12/18) As I remember it is a tapered key with a hook on the outer end so, theoretically, you can pry it out. I have had some luck removing the flywheel by taping it in a bit to losten up the key. There is no penitrant that will help losten the flywheel other than hay dust. You can fight it for hours but take it to the field and use it, the more you need it the better, and it will losten and fall off immediately, in tall grass where you can't find the key. Ask me how I know this.

IIRC, they were NOT a "gib-head key" although they were likely tapered.

NOT sure there's room for a "Gib-head" key without bolt heads on the pitman bearing whacking it.

Hotflashjr · Jun 13, 2018

Bob I think you replied when I had the exact situation. Ended up mangling the flywheel and having to get a used one - also to replace the leaking seal.

I also will add to try and move the seal so it doesn't ride on the same spot on the shaft if there is wear or add a sleeve on the shaft. On the No. 5 I had I ended up using a sleeve because there were a few grooves already.

Question about a number 5 JD mower

Dr. Bert

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David from Kansas

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Bob

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ET

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Destroked 450

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Dr. Bert

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Hayfarmer

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Bob

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Hotflashjr

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