Unfortunately, the service manual for your model isn't available. The following link is from the Vintage Airstream Club website.
Frequently Asked Questions
The first owners manuals were published in 1964
. Prior to that, the owner received a brown envelope containing parts lists and other helpful information on the accessories in his trailer. The VAC has started making these available in the Members Archive section. A service manual with instructions for performing service operations did not exist until 1972.
You can get photocopies of owners manual (1964+) and service manuals (1972-1986) from:
Helen Davis Secretarial Services
PO Box 484 Sidney, OH 45365
Prices are about $33 and $70 respectively. After 1986 the Owners Manuals included available service information.
Also here's the link to the Airstream book store who sells owner's and service manuals. Unfortunately no service manuals there either prior to 1972.