Hello bwdbrn1 !
Thanks for the helpful links. It's not exactly "my" machine but quite similar.
As soon as i have the serial-number I may be able to get the exact production year to get any further information.
As it's a used machine the tread depth of the caterpillar drive is 'only' about
1/2 inch / approx. 10 mm.
Will it get enough grip to work with it or do i have to replace them soon ?