For visual modifications I used pictures from internet. Found one image with cabin and used it as blueprint for cabin.
Most parts are assembled with M3 bolts and nuts. All details for parts and assembly guide you can find in FreeCAD (.FCStd) file.
I used ZGB37RG 60rpm 12V motor, but for better torque I recommend lower rpm motor. For terrain like grass, my motors are to weak.
Parts with fewer details I used 0.3mm layer height. Smaller parts printed with 0.2mm or 0.15mm layer height. If you want better visual quality, then use 0.15mm layer height.
Printed parts:
22 x original parts (no modifications)
133 x modified & new parts
Mechanical parts:
2 x M2 10mm bolt (roof light)
2 x M2 nut (roof light)
14 x M3 6mm bolt (12 pcs to motors)
2 x M3 8mm bolt (seat spring)
12 x M3 10mm bolt
17 x M3 12mm bolt
6 x M3 12mm bolt (without head)
8 x M3 14mm bolt
6 x M3 16mm bolt
78 x M3 18mm bolt (62 pcs for chain)
9 x M3 20mm bolt
3 x M3 25mm bolt
8 x M3 40mm bolt
79 x M3 nut
70 x M3 nut (self locking) (62 pcs for chain)
18 x M4 14mm bolt
18 x M4 nut
2 x M6 40mm bolt (countersunk) (for lead wheel)
2 x M6 nut (self locking) (for lead wheel)
2 x ZGB37RG motor 2 pcs
2 x 10x10x220mm aluminium square tube
10 x 10x2mm round magnet
6 x 13x5x6mm ball bearing
Notes:
It takes around 160 hours to print (if only 1 printer is used)
Parts are designed for 0.3mm or 0.2mm layer height
Some parts are printed with brim
Longest print time for one part is around 9 hours (if 0.3mm layer height is used)
I used A2 stainless steel bolts & nuts
Some original parts must be glued together, I used "4 minute" epoxy.
oc3_print_mod_y_part_005 adds some strength but is not directly necessary. Designed as place holder for servo mount (future upgrade).
You can use 5050 SMD LED's for roof lights. As light covers, use TAMIYA High Lift truck (or analogs) roof lights glasses.
chain_link_mod_y_left.stl & chain_link_mod_y_right.stl are based on original design. But this type chain caused to much wobble. For better stability use oc3_print_mod_y_part_072.stl & oc3_print_mod_y_part_073.stl
You need to print 31 pcs left side chain links and 31 pcs right side chain links.
Parts orientation in .stl files are random. You need to position them correctly yourself. Most parts do not need support if you place these right way.