Plymouth issued its first repair manual in 1934. Prior to that, no repair manual exists for Plymouth. You will find the owner's manual helpful, as it contains much repair. You can also use the 1928-1933 Plymouth parts book for a reference, because it shows exploded views of the parts which are helpful when working on the cars. If you have a 1933 car, you might also consider using the 1934-1936 repair manual, since the cars are similar.