Angle of Brake Arms

[RawhideKid]

After reading waaaaay too many postings on brake adjustment, and the Service Bulletin Nov 1928 pg. 298, 299, 300, I am a bit confused.

From all the postings and advice I have determined that the Front arms need to be set at a 15° angle, but I am not sure what the rear brake arm angle is to be before adjusting the rods to length. According to the Service Bulletin, it says nothing about a starting angle of the arms before starting the brake rod adjustment.

While I am at it, what about the E-brake arms?

Thanks.