Contact Robert Paul in Yoder Colorado . He rebullds original A shocks; he also has rebuilt spares; he is knowledgeable about the Judging Standards so will know 31 Shocks; he is reasonable with his prices.
I have had four sets of shocks rebuilt by him and have never had even one show any leakage.
Paul's telephone number : 719-478-5102
If you get the MARC magazine "Model A News", Robert Paul's add is in the magazine.
Ron