[clampdaddy]

Does anyone know if there is a published min. service thickness for the drive disc on a model A? One of mine is rust pitted and I'd like to re-surface it but I don't know how far I can go with it and still keep a proper functioning clutch.

 

[bill z]

Need more information here.

What year is your Model A? Makes a difference due to increased horse power in later years.

Also, which plate are you having problems with?

How warn are your clutch plates or are you going to replace them. There is adjustments that can be made assuming you have not already bottomed them out.

 

[clampdaddy]

It's a '51 A and I'm referring to the main drive disk (I'm just going to replace the thin sliding disk and all of the frictions). The tractor sat for a long time without a clutch cover so everything is pitted. I think that if I can turn .010 off each side of the drive it'll be good as new, but like brake rotors, I'm assuming that there is some standard minimum thickness that should be paid attention to.

 

[Steve(MO)]

I don't have a manual for a Model A, but I do have a factory manual for a 2 cyl. 820, and it just says to replace the drive plate if it is cracked or has worn splines.
I really don't think taking .010 off each side would cause any issues.
Brake rotors will warp if they are too thin because they can't dissipate heat as well as one that is "in spec".
The clutch doesn't get anywhere near as hot as a brake does, so it should be o.k.
I hope this answers your question.

 

[clampdaddy]

Good point. I never thought about heat being a deciding factor. I'll give it a go. It won't cost anything but my time so the worst thing that can happen is I finnish ruining an already ruined disk.