Google Hydrovac rebuilders and see if they will sell you the part. Not to long ago someone here on the Bolt had the unit rebuilt and named the company, do a search and check them out.
Mike B
Mike Boteler
1956 Chevy 3100 Resto Rod 1952 Willys M38 Army Jeep 1983 Jeep CJ7 Laredo 1984 Jeep CJ7 +++++ Silver Spring, MD