Packard Forum Index » General

I'm just wondering if Ross Miller ever posted the vacuum side rebuild of the Bendix-Treadlevac?Because if I'm tearing this think open,I don't want to do half a job (HYD.side)then find out I have a vacuum problem after I've got it back in.
Thank again for all your help.BillW

Not yet! But here is the short course, since I don't know when I'll get around to it:

52-54 models with a spool valve, no poppets: make sure the spool valve moves freely in its bore. Lube it with the tiniest bit of white lithium grease. Makes sure that the diaphragm in between the two power piston halves is not breached, and that the little tiny vent hole on the far side is not plugged. In other words, if you cover that little hole with your finger you should not be able to collapse the diaphragm. If you uncover the hole, you should.

55-56 models also have the plunger and diaphragm, and have two little rubber faced poppet valves that are accessable after the two casting halves are separated. They are mounted on wee tiny swivels that need to be freed up. The rubber faces can be renewed by carefully gluing on new rubber discs. You will probably have to make these yourself. The old rubbers will be deeply indented; they are supposed to be flat. When they are deformed the brakes are very hard to modulate and the boost tends to come on late and hard.

When you have the the complete TV back together you can easily test the vacuum section: Stick a piece of vacuum tubing on the port and suck on it with your mouth. You should be able to depress the master cylinder with a finger.

Wonderful info.

Not to diminish your contributions in any way, but the BTV is a lot simpler (and more effective) than most people realize - especially those who never had one apart.

In the one '56 unit that I had completely apart, the rubber discs were actually in good condition, but separating from the brass valve due to sheer old age. IIRC, I re-bonded them with 3M Super Weatherstrip adhesive - now, wondering what you recommned.

Also, as you know, when the BTV vacuum piston assembly has to be disassembled, if done carefully, the gasket for the two halves (Gr. 1.359, same for all 52-56) can be reused.

As always, thanks for the great tips, Ross - keep 'em coming.

thanks very much for the info.will let you know how it works out.BillW