I wanted to get a copy of the factory drawing for the A 3131 B left side spindle arm (2 ball side). looking on the MAFFI site I found 84 entries of drawings for that part, spanning from 1927 to 1930. How does a person know which one to order? I need a machining drawing with dimensions to check my spindle arm,and would like to get the correct drawing. Can anyone tell me of their experiences using the MAFFI service for part drawings? Thank You, Terry