NAPA has been a good source for oddball brake parts, as long as someone at the local store is willing to get back into their stash of paper catalogs. When I was working on Ed's big GMC 530, they actually had a source for front wheel cylinders- - - -for $96.00 each- - - -two per wheel! I ended up honing the old ones several thousandths oversize and making new aluminum pistons for them. NAPA had the rubber cylinder cups available on open stock, and they were able to accommodate the oversize bores without leaking. Sometimes it's necessary to get a little creative when working on trucks bigger than a pickup. The demand for those parts just doesn't justify keeping them in stock or making new ones.
Jerry
