1970 Yard-Man EarthBird Tiller Problem

[philadelphia1]

1970 Yard-Man EarthBird Tiller
Model # 5010-01

Hello Kind Professionals,

I have an old 1970 yard-man earthbird tiller that has been in my family 40 years and is a great piece of machinery, until recently. The other day while tilling the tines stopped. Had this tiller 40yrs and no problems other than an engine replacement (1984). Engine is strong and runs well. Replaced forward and reverse belts last year....tension is proper and no slipping.

I am thinking that something happened in the gear box assembly (pumpkin). An if so? Suggestions as to what it might be?

Has anyone worked on this particular unit ?

I attached a YouTube video link that shows the problem better than i can describe. Also a "pdf" attachment with exploded view of tiller assembly.

I am aware of the seal leak on the left side and always keep gear box filled with oil.


1970 Yard-Man EarthBird Tiller - YouTube


Thanks for you time. Any help is greatly appreciated!

Regards,

Here in Philly

 

[aandpdan]

Nice machine. I have the 1963 version with the original 4hp Briggs.

There are pins on the shaft that hold the tines that can shear. There is also a roll pin on the pulley to the shaft. Otherwise, if you turn the large pulley and the tines don't move you've had a gearbox failure.

 

[philadelphia1]

There is nothing better than these older machines, as you know aandpdan.

I am aware of the pins on the tines. It was my first suspicion but they are both ok. The roll pin in the main shaft is ok. When I turn the main pulley the tines spin but slightly. This is what baffles me???:confused2:

 

[EngineMan]

It can be one of the cotter pins on the puller/shaft(s) or one of the worms (or both) I would take it apart it shouldn't be that difficult to do,takes me back a bit, lovely old tiller. when you do come back and let us know.

 

[aandpdan]

Double check that roll pin, it can look OK but be fractured in the middle and spin on the shaft.

Otherwise, if you do take apart the gearbox please take some pictures. There's probably a key in there somewhere.

It was my grandfather's tiller. It's one of those things I have to keep running, been almost 30 years now. :smile:

Good luck.

 

[philadelphia1]

Hello Friends,

Sorry it took so long to respond back, had to replace a timing belt on a neighbors car. Been swamped with work lately. Anyway, i opened the gearbox and sure enough i sheared a groove pin on one of the gears. Please see pics.


Have a look at this youtube video of the main gear... Appears to be moderate damage?

Considering the damage you see, do you think this equipment will function if i purchase another groove pin and install it? How about the main gear... will the worm still spin the main gear? might it slip? Is the damage on the main gear normal wear and tear (of 40yrs.) or that done by the sheared pin? Or perhaps a combination of the both?

There are very fine shards of metal throughout the gearbox... and all over the shaft bearing that concerns me.......should i use gum cutter or spray silicone lubericant to flush the bearings of this metal? The worm gear looks good with only metal shavings on it...

Any suggestions on what you see from the video and pictures so far? Thanks for your help.

Regards,

Here in Philly

 

[aandpdan]

Thanks for the pictures Philadelphia1,

Clean it up, good. I'd use brake cleaner to spray off the parts. Some light metal would be expected, the fine powder you see.

The pinion gear looks rough. The wear pattern looks like its had a lot of hard use. I don't know if you'll be able to find another so just put it back together and see what happens. If you're easy on the tiller it should last a while.

Good luck.

 

[philadelphia1]

Hello Friends,

I wondering if anyone could help me find a pin for my gearbox? If you look at item 29 on the pdf file i posted earlier it's listed as a groove pin with specs 5/16 dia. x 2". Anyone know where i can find that specific pin?

I took the gearbox to my local MTD service shop and they did not have a groove pin with those specs and could not find a part # through MTD being that the tiller is 40yrs old. So the service guy sold me a rolled pin that is close in specs but warned me that the roll pin tolerances might be different resulting in futher damage to my gearbox by not snapping at the orginally perscribed stress point.



Here is the original groove pin... It is a solid pin as opposed to the the roll pin which is hollow...


So at this point i'm not sure what to do? Gamble and go with the roll pin which might result in further damage to an already considerably damaged gearbox or keep hunting for a groove pin with OEM specs?

Can anyone help me find a groove pin with OEM specs?

Any advice is appreciated!

Here in Filth-a-delphia

 

[EngineMan]

Hello Friends,

I wondering if anyone could help me find a pin for my gearbox? If you look at item 29 on the pdf file i posted earlier it's listed as a groove pin with specs 5/16 dia. x 2". Anyone know where i can find that specific pin?

I took the gearbox to my local MTD service shop and they did not have a groove pin with those specs and could not find a part # through MTD being that the tiller is 40yrs old. So the service guy sold me a rolled pin that is close in specs but warned me that the roll pin tolerances might be different resulting in futher damage to my gearbox by not snapping at the orginally perscribed stress point.



Here is the original groove pin...View attachment 17207 It is a solid pin as opposed to the the roll pin which is hollow...View attachment 17208


So at this point i'm not sure what to do? Gamble and go with the roll pin which might result in further damage to an already considerably damaged gearbox or keep hunting for a groove pin with OEM specs?

Can anyone help me find a groove pin with OEM specs?

Any advice is appreciated!

Here in Filth-a-delphia

You could make one out of 5/16 bolt by removing the head and tail (thread)...! but I can't see a problem with the roll pin myself, if you are unsure, fit other one inside the first.

 

[Native2ky]

You could make one out of 5/16 bolt by removing the head and tail (thread)...! but I can't see a problem with the roll pin myself, if you are unsure, fit other one inside the first.

Did you fix the pin and problem. I have the same machine and my tines turn but stop when under a load. But they sometimes catch under load and do fine. I've checked all pins, disassembled the drive train and only severely worn part is the worm gear spacer. I can't find the part but if I had the original dimensions of the part I could make one. Can anyone help? Thanks!