Mopar Action On-line – Tech Questions
Joe Jura, Downers Grove, IL, 1969 Plymouth Road Runner 496″
Richard, I bought a March serpentine pulley set for my Road Runner. I removed the alternator pulley and took alternator and new pulley to local auto parts store/machine shop and asked them to press on new pulley. The old timer there told me that they cannot press the pulley on because there is possibility of damaging the bearings. I was told to drill and tap the alternater shaft in order to install. I inquired as to how the existing pulley that I removed was pressed on and was told that it was pressed on before final assembly. I left the shop and decided to drill and tap. The shaft is diamond hard and my drill press mounted bit could not hardly scuff it. I then decided to take it apart and take back to machine shop and have it pressed on. However when I started to disassemble the housing I did not see how pulley could be pressed on before final assembly.
Whats the deal?
Joe, the deal is pretty simple. The press work is done with the alternator partially assembled. You simply pull out the brushes and the rear (i.e., inner) half of the casting, which contains the needle bearing. Now you have the front half, with the thrust bearing still installed, in your hand, with the back end of the shaft sitting there bare – ready to sit on the press plate. From there, it’s about a 30 second press job (see pix). Slime a small amount of high-temp grease in the rear bearing before assembly.
The old timer at the shop must have brain fade, because this is how it’s been done since 1960, when this design alternator was released.