Tredle Vac

[creeves]

My car as converted to a dual master cylinder before I bought the var. The brakes are horrible, and I have had a quality shop working on it and we have decided that the factory knew best and want to move back to the Tredle Vac system and return to the factory spec's. The front brakes show little pressure till the end and then lock up, we have added a valve, but still no luck.

My question is I have no core, so many won't sell the unit without a core. Is there a conversion to other like a T-Bird/Mercury or other Ford part that may not carry the extreme price tag. I still don't have a core but know that other part numbers may be more available so not an important for a core.

Any advice is appreciated.

[Milsteads Garage]

I traded 2 treadle vacs to Barry Wolk a while back. You could ask him and see if he wants to sell one.

[Barry Wolk]

I might just do that.

Anything to trade?

[creeves]

I wish I did have a group of parts to trade. It may be a long shot; I have two large hides, Bridge of Weir in dark red that I over bought when I had the interior done that I won't be using. Overall, I have been trying to restore, reuse, and generally clean-up to original as much as possible! So, all serviceable parts have been reused. If you would consider selling one, I would be interested. I have been following your work, and I can share my vision of C56B2076 so you know the unit is going to a good home :)! Please let me know if you would consider. Thank you!

[Barry Wolk]

Make me an offer I can't refuse. I don't even know which internals they have. If you have the choice buy a refurbished sleeve valve unit over a poppet unit. The poppet type is too "grabby" for my tastes, but the car will have a vacuum leak every time you put your foot on the pedal at a light. You can hear and feel the change.

[creeves]

Hi Barry- I sent you a DM on the offer. Please review the message and let me know. Thanks- Chris Reeves

[Barry Wolk]

Your offer is appropriate. I’ll open them both and send you the best of the two. If they’re not salvageable I’ll let you know.

[creeves]

Thanks Barry- I sent you an e-mail as well. If you can let me know the payment method and what info you need, and I will send the money. Thank you again, helping me get the car back on the road!

Chris

[Barry Wolk]

Only one of the vacuum chambers I got from Morgan was salvageable. Fortunately, I still had the chamber that Mad Scientist gave me 20 years ago.

The early units were exposed zinc plated that rusted with the slightest scratch, likely the reason they painted over the zinc on later units. Due to interior imperfections I'm going to have the two good units heavy zinc-plated so I can sand imperfections out of the bore on my lathe.

I have enough parts for two units, but I need these parts to complete them. One for you, and one for me. I tire of my car sounding so terrible at traffic lights when I depress the pedal my on my early sleeve valve T-V.


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[Barry Wolk]

All of the first day production photos show an unpainted T-V.

32147

[Barry Wolk]

Chris and I have come to an agreement. I believe I have the parts to make two identical units. I've ordered 2 poppet valve kits, the most extensive kit I've seen. It even includes a new stainless steel shaft. Roger Z. is the one that clued me in that Cadillac parts dealer offered one for $85.00 This comprehensive kit was under $250, including the new stainless ram.

Many of the early production photos show a zinc-plated, unpainted tank. They were later painted black to cover the inevitable scratches it received in manufacturing process. All three tanks in my possession have never had paint on them. I later discovered that the badly rusted tank had no drain hole, ever. QC problems?

Due to the way a Mark II is parked can lead to problems, also. A normal garage floor has a pitch to it. It rises as you pull in. That pitch is sufficient to make any accumulated water or brake fluid drip out the drain hole and onto the garage floor, not the firewall. However, if you back in water will pool inside the vacuum chamber and rust it badly on the inside.

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[Barry Wolk]

Said kit. The only think I don't see is the large vacuum shuttle diaphragm that has the spring attached. The 3 I have look OK, but I'd rather have a new one.

https://www.parts123.com/parts123/yb.dll?parta~dyndetail~Z5Z5Z50001029z~Z5Z5Z5AAIAL~ P235.95~~~~S6YF0JCDNX97701579903a~Z5Z5Z5~Z5Z5Z5000 1029z

[Roger Zimmermann]

This kit seems to be rather complete, compared to the ones from other suppliers. The diaphragm you cited can be damaged, rendering the unit to be inoperative.

[Barry Wolk]

Roger, aside from the obvious visual inspection, how would one test the diaphragm?

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[Barry Wolk]

The kit they offered did not include this kit. I can't imagine reusing 70 year-old parts, if I don't have to. It turns out, from their notes, that all the '53-'55 T-Vs had the slide valve, but the brass sleeve wore, creating a vacuum leak. They make a kit for repairing them, or they will provide that service, or rebuilding the whole thing, at a price. If that valve wears too far you lose just your power brakes.

Since I'm concentrating on rebuilding two of the later T-Vs made specifically for Continentals I'll report on those. That's $370 in parts for each unit. However, stack up the same type of Harley or airplane parts and you'd be looking at a much smaller pile.

https://www.parts123.com/parts123/yb.dll?parta~partsort~1~cadfffkz~~20

Edit: look up part number 62-1355 on the link above.

[Roger Zimmermann]

Roger, aside from the obvious visual inspection, how would one test the diaphragm?

32151
Honestly, I don't know.

[Barry Wolk]

Honestly, I don't know.

Nor I. I'd hate to go through all this work to have I not work, so the $135 extra for the kit is worth it.

The tech guy at Harmons says that TV canisters were never plated from the factory, but none of three I have shown any sign of ever being painted black.

On of the T-Vs I got from Morgan had been rebuild with parts from other models. Fortunately, one was easily altered. The internal parts showed no sign of paint, but it appears they are painted when you pay them for the build. Someone made my life miserable by using a silicone sealer when the cork gasket is fine for vacuum.

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[Roger Zimmermann]

Someone made my life miserable by using a silicone sealer when the cork gasket is fine for vacuum.



That product is too often misused.

[Barry Wolk]

Nothing but kudos for harmonclassicbrakes.com. All high quality parts, not oversized one-off recasts. Everything is die cut, no trimming or alteration required.

I found the power piston has a lot more parts for the poppet style than the sleeve valve type. I'm speculating, but I'm pretty sure most of the 1955 cars got sleeve-valve boosters. I believe they worked great until the bronze sleeve valve wore. Since they stopped making them for 1956 the direct replacement was the poppet valve vacuum control. They didn't make anymore sleeve valve units as the poppet were made as direct replacements. I have surmised that they recognized the problem and dealt with it in a practical and longer-lasting way. I'm sure Lincoln was not happy about the failure rate, either.

The problem is one that I encountered when I needed to rebuild my sleeve valve is that no one wanted to do the machining on a known worn unit and sleeve valve units that worked became scarce. Replacement units were still available in poppet style. Here's the rub, the sleeve valve units decrease in power to the piston the more the sleeve valve wears until you no longer have any assist at all, just a big vacuum leak when you put your foot on the pedal. Does your car idle funny at a light when you put your foot on the brake at a stoplight? It's likely a sleeve valve type.

32159

[Barry Wolk]

Well, I've turned two trash heap T-Vs and a pile of spare parts into two things of beauty. I had only done slide valve rebuilds made from 1954 through 1955. They must have discovered that those models became pretty useless because they quit making them, altogether. The slide valve refers to the means the vacuum is turned on by one cylinder moving inside another until their vacuum ports line up as you move the pedal lightly with your foot. There's about 3/8" of movement to make the vacuum passages line up. Once vacuum is allowed into the cylinder vacuum pulls the power piston away from you and into the cylinder pushing the rod that displaces brake fluid in the master cylinder. That's power assist.

When the rod enters the master cylinder it displaces fluid in the chamber. The only place it can go is out to the wheel cylinders where the pressurized brake fluid causes the brake shoes to be pushed apart with their abrasive material rubbing on the inside of an iron or steel brake drum creating the friction necessary to stop the car. As soon as you let off the brakes vacuum is shut off and the forward movement of the stainless steel rod slowly stops and is pushed all of the way out of the master cylinder by another force, spring pressure, pulling both brake shoes to their rests on all 4 wheels. That spring energy is converted to hydraulic pressure that returns the rod to its most retracted position by pushing the fluid back into the master cylinder under pressure. There is a device that makes the return of the pedal slowly return to normal position. When the return process in completed a washer on the end of the rod trips the tilt switch, opening the means for fresh fluid to flow into the master cylinder, compensating for the loss of brake fluid while driving. If your tilt switch is not being activated your fluid is not being topped off automatically.

I used the hose clamps provided on the cast rubber vacuum hose. If you used water or fuel line they will collapse the moment you start the engine. It's designed for pressure, not vacuum. You can use a hose clamp on the power piston side of the hose, but using a spiral clamp on the check-valve side the shuttle cannot fully retract to open the compensating valve because the clamp thickness lessens the travel the compensating valve needs. That 1/32" makes a difference.

The sleeve valve was a great car stopper to begin with, but the tiniest bit of wear would ruin braking capacity until you had nothing but a big vacuum leak which badly affected the way the car ran and the way anything with a vacuum motor operated. Antenna, heating and cooling controls and wipers would all be affected, even the way the car ran as low vacuum affects timing. The poppet type used in '56 and '57 was an answer to a problem no one knew they had. The only whole units available after the beginning of 1956 were poppet type, a much more effective way of turning the vacuum on and off with the tap of the brake pedal. They lasted considerably longer than the sleeve-valve. I'm surmising that maybe 5% of the sleeve valve remain.

I was fortunate enough to have been given a Treadle-Vac when Mad Scientist walked amongst us. He inherited the family's Mark II and turned it into an admitted FrankenMark, changing every single system he could. He describe it as sadly neglected in need of some electronics. He solved the low fuel relay that did, electronically, what the original did with very fragile components. He was my hero, and my antagonist at the same time. He asked me one day if I would like a brand new Treadle-Vac he had no use for, digging it in that he had gone the disc-brake dual master cylinder route of his own design . I might have trusted what he designed. I stuck the T-V on the shelf. It had a Ford part number and the unit was stamped F specifically for the Mark II. It was a galvanized vacuum chamber and no green plating on the MC. It had a Continental part number in a dark crayon on the zinc plated canister. Now I have to see if I took pictures. The other two T-Vs came to me in exchange for an original metal filler hose that looked new. Until he reminded me that he had traded me the two units I could offer no help to Chris in his quest for solving his braking dilemma. He needed a working T-V to reverse brake work done by a previous owner that no one could make work right. He needed a core and offered decent money for one. He also made an offer for a unit rebuilt. I tore open the box of two I had forgotten about and found that could make 2 out the best parts of 3 and found that Harmon Classic Brakes offered the most complete kits I had ever seen. I had Chris order kits for two complete units had them delivered to our house. I set about messing up every plan I had for a 2 week period while I media blasted all the parts, even treating the zinc die cast master cylinders to glass beading that left them better looking than new. The kits were missing a couple of gaskets that I easily made, but it was very complete, overall.

I swore 10 years ago that I'd never work on anything with a deadline, but there I was. He was hoping to get the brakes working right before its appointment with an upholsterer and I set about making it happen.
It was just as easy to build two side by side, but did a boat load of preliminary work to get to the assembly. After chasing every thread and wire brushing every fastener I was able to get his out the door as I took a breath of relief. The second T-V is going in my Mark II to replace the acid-damaged unit. I will rebuild that sleeve valve unit and will install it, even for a short time so I can report on a new to new comparison.

I hope this resolves Chris' brake-bias problem. If I were younger I'd start a business reversing disc brake and dual master conversions for people tired of standing their car on their nose every time they hit the pedal. I wish there was a way for people to compare new drum to new disc before throwing a parts package at a car put together by a retailer that's not a brake engineer. I'm not one, but I don't claim to know everything. What I do know is that properly set up factory brakes will serve you well using the best engineering of the time. Having an operable emergency emergency brake resolves 90% of the safety issues and new flexible brake lines solves the other 10%. In fact, the US banned lawn darts as too dangerous, but drum brakes are still used extensively on semis and the rears of many production cars. Why is that?

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[Milsteads Garage]

Glad I could help. That fuel filler pipe worked wonderfully since they are not being made anymore. I’m half way tempted to take the fuel filler pipe back out and make some copies of it.