Re: 1953 Patrician: has anyone updated from Treadlevac to modern 2-chamber mstr cyl?

Posted by HH56 On 2024/5/19 22:32:07
Has anyone tried to take a dual master, such as from a Chevy, and stick it on the Packard TV?

Seems like there is an old discussion on the forum but don't think it has been tried. Think the consensus was you would not gain anything because the BTV works on the fact a large long stroke ram moves into a confined space and displaces or squeezes fluid out principle while modern masters work by having a fairly large piston pushing a volume of fluid ahead of it. The advantage of the fluid being forcibly displaced is lost so the BTV mod would be essentially an older booster instead of a modern booster. It would still need to move to get a decent pedal ratio to work the piston. That Chevy BTV replacement works as a direct swap for Chevy's because they mounted their BTV near the top of the firewall and had a high pedal ratio from the start.

To make a mod work a plate needs to be made to attach to the end of the BTV canister. It needs to generally follow what is in the mounting end of hydraulic portion of the BTV so it can be a rod guide, a rod support, and have seals so the vacuum can be confined in the canister portion. Whatever is used for a new rod must be smooth enough for a seal, substantial enough to be supported in the new plate and kept from tilting because the BTV ram end fits in a socket on the power piston and is the only thing that supports and keeps the power piston straight in the canister so it can move.

You might be able to make a thick plate that has a bore to provide the rod guide and seals for the vacuum. Also needs to be thick enough to have threaded holes so the new master can bolt to it. One end of the new rod must fit the power piston and the other end be narrow enough to be able to seat in the new master piston with its smaller diameter pocket sized for a modern push rod. Possibly the old ram could be machined to work but it is probably hardened. I think it was decided it was much work for zero gain.

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