3b Rear Wheel Assy 

368 Lubricator, Rear Wheel, is an oil cup with a spring loaded hinged cap, that most probably should not be used, as the rear axle is lubricated with grease and not with oil. 

For information on 365-Spokes, see 3a Front Wheel Assy

For information about 318-Tyres, see 3a-Front Wheel