Lawnflite 703 Autodrive. PTO clutch for deck drive was slipping, so I
decided to have a go at it. I have looked at it before, a mechanically
operated clutch (rather than electrical) and then I found it was simply
metal face, to metal face - no sign of any friction material, but it
worked, so maybe that was how it was designed to work?

I have been unable to find a proper manual for it or any sort of
diagram of the tractor or the clutch, nor even a replacement clutch,
though I have not looked too hard for the latter.

It uses three balls, in deepening slots to engage disengage, with a
strong spring to engage and a light concentric spring to push the
plates apart.

Lacking any better idea, I thought to try a bit of thin card to act as
friction material between the two metal plates, but couldn't find any
suitable. What I did find was some material marked Novus Econostus
1.5mm which has been laying about in my workshop for decades, probably
intended as gasket material of some sort (light browny orange colour),
so I cut some of that into a disk and super glued it to the clutch
plate.

Drive to cutting deck now seems to work fine, but for how long? I
cannot see the clutch being under much stress, because it has sort of
worked metal to metal for the past few years.