today Crosman owns the Benjamin line of airguns. See the attached link for service centers. http://www.crosman.com/general/find-a-service-center
Best left to a professional, cost might exceed worth of the air weapon.
see the link below:
It started in 1946 to 1985
this pistol was made between 1979-89. I suggest that you do a web search under "Air gun repair" and locate a shop near you that can repair the pistol.
Produced between 1946 - 85 as models 130, 132 and last as 137. Please state the condition of the pistol to get an estimate of value. Poor, Fair, Good, Very good or Excellent.
Take it to a authorized repair center
Contact the maker for a list of repair centers.
Check the web on "Air Gun Repair" and find a shop near you for repairs.
In very good condition it would be worth between $65 - $80
They were made from 1946 to 1985. If you gave me the serial number I might be able to give you a year.
Benjamin made this model from 1946 to 1985, but did not start serializing them until 1957. I also have a Benjamin Franklin that has no serial number. Before 1957 it is not possible to set an exact date. Just know it's OLD. The 137 is a .177 caliber pellet pistol the 132 is a .22 caliber pistol and the 130 is a BB pistol.
Try e-gunparts.com