Packard Forum Index » Post-War (1946-54)

I just went to the Bendix web site and did a search but came up empty handed for anything about treadle-vac or treadle vac (no hyphen).

Quote:

You're correct in there are two main seals, but one is leather and almost worthless for retaining fluid. The other referred to as the cup seal is a single lip rubber seal where the inner circumference lip rubs the piston and the outer lip circumference does the bore. That piece does the actual work of sealing fluid. The ring seal is a third piece but not much more than decoration to keep fluid from falling on the ground as near as I can tell.

It may not be a terribly common occurrence but I have seen more than one BTV that has sat unused for long periods where due to whatever reason, the shaft has pitted in the area where the lip has sat. Suspect contamination in the fluid as the culprit but even if the damaged area is not in contact with the seal at all times, when the unit is put into service again, just in passing the rough area (even with a new seal) there is eventual damage and a leak--old hard 50 year old seals are another issue. Granted, new SS pistons are available, but not all go to the effort when rebuilding and just replace the seals that come in the kits. As to the new MC's, I and many others would appreciate info.

As to the different designs between manufacturers--that is another area where lots would like more info. If you could enlighten that would also be appreciated. That has been one area of speculation as to why Packards seem to have failures and other mfgs apparently don't--something different in the design.

humm ok, i'll have to try to find a "packard" core to look at! whatever the one is that uncle put on the greendragon, it's not packard. the m/c looks packard, but is made different. the rear seal is/was a double, double lip seal. and it did not have the port from the resivor you mentioned. and the vac piston in the booster is different, it has a total of about four parts in it. unlike the packard, with poppets and springs and pivots and all that junk! it has been a long time since i rebuilt a "packard" unit, so i would say my memory is failing me here. i thought the m/c's were the same.

As for the new m/c, i work for an auto parts company. one day on down time i decided to call bendix and see if they could shed some light on what the "dragon's" t/v came off of. at first the man i got (jon) didn't have a clue what i was talking about. when i told him i would need to speak to some one who had been there long enough to have delt with 50's era cars. he said he had. once i got him to listen long enough to explain that the unit was the same or simalar to what was used on vettes and tri-5 chevys, he knew what i was talking about. he did some hard core digging while we were on the phone, rattled off all the other cars the t/v was used on, and then got real quiet. he said " we still offer a new replacement m/c for that unit!"
he produced a part number, which i believe was 57001 and i ordered one. guess what i got? a brand-new fresh stock t/v m/c! that has been 5 years ago. i have not tried to get one since. they may have quit offering it now, might be why you couldn't find it on-line. but i know it was not easy for jon, the guy at bendix to find either. and he works there! he said he finaly found it as a listing for a heavy truck maker in the 60's. and i would think as popular as vetts and tri-5's are they would have kept them around.

" whatever the one is that uncle put on the greendragon, it's not packard. the m/c looks packard, but is made different. "

A picture would help. Maybe someone will recognize it.

Thanks for the 57001 number.