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

Welcome Joe - glad to have you on the forum.
You will find pros and cons on the Treadlevac issue.
I have run it for many years on my 56 400.
Other people have had it fail even when built by "reputable" shops.
I rebuilt my own way back in the early sixties when a 56 400 was my daily driver. It worked flawlessly for me for several years.
Do some reading and come back and let us know your decision.

I would really like to just use what I have. With money being tight though what's my best choice? To be honest I haven't had a whole lot of time to look thru all the topics that came up on the search. I will try to get back at it in the morning. Pretty sure that kanter offers a rebuild kit though

With many of us cost is always a consideration just as keeping it original is too. If you go with the rebuild kit from Kanters you knock both of those over in one hit. Plus Fred Kanter used to post on this Site and was offering in this thread, and in other threads, a swap deal on old for rebuilt Treadle Vacs. Fred wanted the old Treadle Vacs for research purposes to determine the cause of the failures. Don't know if the offer still stands but it couldn't hurt to get in contact with Fred and see if it does.

If the decision is made to remain with the BTV then i would strongly recommend buying a complete rebuilt unit. i.e. i would not recommend just a rebuild kit as a DIY project.

Read thru the many posts regarding the BTV then decide to keep it or convert. Keep us posted on your results.

The Kanter route is definitly an option, I did not know about the swap. I went the Ed Strain route. He is a rebuilder of of BTV units. I have done 3 thru him and have been pleased with all. The last one I did ran $230 including shipping.

ALK

Also be aware that the BTV requires periodic proper service and maintenance by a qualified BTV service provider. The current claim (anyone please correct me if i am wrong) is:

To drain and flush ENTIRE brake system every 6 months to 3 years max. AND to have the BTV unit completely rebuilt by a qualified experienced BTV service provider every 3 years to 5 years.

Note however that there is NO OFFICIAL PACKARD Motor Car Company documentation to support the currently accepted maintenance schedule as listed above.

Look thru the BTV topics and u will find the above periodic service recommendation indicated.

Like Al, my BTV was rebuilt by Ed Strain some 12 years ago and no problems. I've also been involved in quite a few other installations of Strain units, no problems with them either. And I'm sure Kanter uses a reputable rebuilder. I use DOT-4 and every 3 or 4 years do a thorough bleed to replace most (but not all) of the fluid.

The Bendix Treadle-Vac was used on about a dozen makes of cars between 1953 and 1963, including Mercedes Benz, Nash, Hudson, Packard and most of the GM makes, probably millions and millions were in service with apparently no unusual problems in that era. There is no doubt that there have been some instances of failure in current times. Whether that was due to poor quality rebuilds, poor quality or overage rebuild components, floating "sludge" in the fluid that lodged itself under the compensator valve, or whatever, remains pretty much unknown as to facts, but theories and speculation abound.

There also is no doubt that dual-master cylinders provide an extra level of safety over single-cylinder systems. If that's of a major concern to you, go with a conversion. If not, have your unit rebuilt by someone who knows what they are doing, and make sure that the fluid in your system is clean and remains that way.

I've had a few BTV units from 55-56 cars apart for various reasons ranging from simple evaluation and as a source of spare parts to minor repair and full rebuild. They use the same hydraulic section as earlier cars, but use a different type of valve in the vacuum piston.

Rebuilding the hydraulic section is a fairly simple. I've used two kits from Kanter, purchased in 1987 and 1990, with no problem, though those cars have been mothballed for over ten years, now.

I suggest you avoid cheap repros of the (minor) rebuild kit, as there have been reports of substandard parts - like the compensator port valve, which is critical to operation - and stick with reputable suppliers. I have an NOS major overhaul kit from Bendix (NOT for sale), with parts for both hydraulic and vacuum section, for reference. The residual pressure check valve in new kits may differ in appearance from what's was originally installed by the factory, but know that Bendix later updated their own kits with a new design/style that is backwardly compatible; repro kits simply followed suit.

Before you decide whether to attempt rebuild yourself, you will need to remove and disassemble your unit for cleaning and inspection. If corroded/pitted, the hydraulic plunger (piston) is now available, separately, in stainless steel repro.

One part that's not serviced is the compensator port valve spring; though it is reportedly made of corrosion-resistant material, I've found one with a weak spot from corrosion, and another one broken in two. If the hydraulic cylinder casting is in poor condition or there are internal issues with vacuum booster operation, you might want to go with a rebuilt/exchange unit - again, from a reputable supplier.

The shop manual provides detailed instructions on how to overhaul the entire unit, but Member Ross (Miller) provided us with a article on HOW TO: Rebuild the Packard Bendix-Treadlevac Master Brake Cylinder that's updated with images and info on several things that the factory never expected.

Now, if you're going to all the trouble with the master cylinder, be sure to also inspect the steel lines, rubber hoses, and wheel cylinders and replace as needed.

WRT to periodic fluid change, DOT-3 and -4 glycol-based fluids are hygroscopic, which means they will absorb moisture from the atmosphere - even through rubber seals and hoses. As such, it's not a bad idea to syphon out the master cylinder reservoir, fill it up with fresh fluid, and bleed all four wheel, pushing another pint or so of fluid through the system. Even with a modern, so-called, sealed system, you would be surprised at the muck that comes out of the wheel cylinders. Hydraulic brake systems in older cars, like our Packards are vented to atmosphere, and the fluid has a tendency to condense and solidify, over time, which is another good reason to push some fresh fluid through it.