Quote:
There is a different kit for 55-6 so wonder what other changes besides vacuum side valves and response were made in the versions Packard used.
I believe the original minor kit includes only the following parts for rebuilding the hydraulic master cylinder:
* cover gasket
* piston cup (rubber)
* piston oil seal (leather)
* vacuum shell gasket
* vacuum shell seal
* vacuum shell end plate gasket
* compensator port valve
* compensator port valve seal
* output fitting seal
* residual check valve/seal
The factory parts books shows same P/Ns for all of these parts between 52-54 & 55-56 EXCEPT for the residual check valve. That one item may be what accounts for the two different numbers for minor kits. While the repro kits that I've used had a different style (flat, disc type) of residual check valve than what came out of the BTVs in my '56 cars, it fit and worked fine.
Although the parts book shows that the compensator port valve is serviced as an assembly, the minor kit includes the valve stem with seal. I've never had a problem with the port valve fitting, but - again - have seen corroded and broken springs.
On a related note, the fill plug gasket (Gr 1.337) (like the compensator prot valve spring) was never included in the minor kits. Because that gasket has been missing from every car I ever inspected, I made replacements from some poly sheet stock. However, I've heard some people talk about a large copper annular gasket (crush washer).
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