John,
You are correct...the J bolts need to be loosened to split the canister and see if the fluid is leaking there. These units are still available from NAPA. It's been a few years since I bought one but I remember it costing about $270.00 and I had to turn mine in as a core.
As for my brush truck, it will be a neat truck when I'm done restoring it. I have a few pictures of what it looked like when it was in service so I can rebuild as close as possible to the way it was.
Mike B
