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Whoops. Here's the pic I meant to attach to my earlier note, showing the top of the Treadlevac master cylinder.

B.

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No, it's not mounted to the firewall on any Packards but rather is attached to a removable floor panel on the lower angled part between the firewall and the floor. Check out the video posted which shows it clearly being removed but don't bother watching the rest as it's not helpful in rebuilding one. Fun to watch but not helpful at all and makes it sound difficult when it isn't, and makes no mention of cleaning anything.

I am curious about the end of the hose seen at the reservoir. Is that the vacuum hose just laying in a strange spot or did those who performed the RH conversion also add a fitting to the reservoir lid to make their own version of a remote fill.

Did they move the vacuum reservoir under the right fender or keep it on the left side and if that is a remote fill hose, what kind and where is the fill container positioned? The stock Packard remote fill option would have been a glass jar mounted at the top of the firewall with the tubing connected to a fitting in the cap.

Good question. Yes, the vacuum reservoir tank is behind the right hand front wheel arch. Looks like it was always there. The hoses are attached to the bottom of it. I think it might be the vacuum pipe you can see near the master cylinder. No sign of a remote filler, but it'd a good idea given that the filler plug on the master cylinder is pretty much impossible to reach. I'll think about that when I have the Treadlevac out for overhaul. I've seen pics of the filler plug tapped with a small hose fitting, presumably to enable remote topping up. How do you check the level? Maybe don't need to if it works like the reservoir on a regular master cylinder.

Cheers

Brian

Thanks Don.

I did watch the video. It was exactly as you say. I noticed that the rubber bellows on the Treadlevac actuating rod were right up behind the pedal on that car. Mine barely protrudes into the interior. Also the rod is attached to the brake pedal further to the left on mine.Not sure yet how the Treadlevac is mounted. I guess all will be revealed when I pull it out! Will let you know what I find.

Beginning to think this thread should be in a blog. It's much longer than I expected, but I have to say very helpful. I have copies of the relevant shop manual sections and feel quite confident about tackling the braking system. Sort of thing you want to know is right.

I guess the patchy reputation of Treadlevacs stems from master cylinder failures, which can happen to any car with a single cylinder. Vacuum system failures are not so catastrophic because the brakes still work - assuming you're strong enough to operate them. I may have been doing this for quite a while without realising it. Can't remember the brakes ever feeling like they were power assisted!

Cheers Brian

The video might be good for an overall look at how things fit together but for detail instructions I would go with the service manual or this excellent How-To article that Ross put together.https://www.packardinfo.com/xoops/html/downloads/BTV_Rebuild.pdf

IMO, the big issue with Treadlevacs is they rely on one seal around the ram and a small circle of rubber forming the compensator valve to tightly seal keeping the fluid inside the master when the pedal is pushed. The seal at the ram can crack or a speck of debris floating in old dirty fluid can prevent the valve seal. A weak spring can let the compensator valve completely fall down away from the seat.

I had promised BigKev that I would scan the Packard Training Manual for Treadlevac and will try to finally get that done when at my Oregon shop in the next week or so as evenings tend to be free there. It's too cold to work in the shop at night and it's pitch black to walk the block back to the house!

Thanks Howard

I have made a copy of Ross' description of the overhaul process for the Treadlevac - looks extremely useful. And better than the video.

As Ross says, these units did not prove troublesome when new, so presumably many of the problems have occurred as a result of subsequent inept repair efforts or failure to change fluid regularly.

The latter issue suggests that silicone (DOT5) fluid might be a good idea when the system is overhauled. Any thoughts/suggestions on this? I have had it in my 1941 120 Club Coupe where it worked a treat. But that had manual brakes.

Will get the car up on a hoist soon to look more closely at the vacuum system. This seems to be the immediate problem with mine, although the entire braking system is certainly due for an overhaul.

Cheers Brian

I use silicone oil and fluid in everything without ever a problem. Just be sure that the system gets pressure-flushed to remove any old fluid and that all the hoses and other rubber bits are of a modern material.

Hello Ross

Yes, you're right it's power brakes.

Howard pointed me to your excellent piece on rebuilding the Treadlevac unit. That will come in very handy when I tackle it.

Have you ever done anything like this for the vacuum side of the system? Seems to be where my immediate problem lies.

Cheers Brian