Buying Into Nanny-State Safety Diktats: Dual-Circuit Brakes For the A100

Ralph Nader’s Unsafe at Any Speed was published in 1965. For the 1967 model year, cars and light trucks sold in the United States were required to have a dual-circuit brake system, so that a single hydraulic leak anywhere in the system would not result in total brake failure. Real drivers knew that they could come to a complete, safe stop using the emergency brake— that’s right, for emergencies— but that wasn’t enough for the feds. They rammed dual-circuit brakes down the throats of the American public, adding at least several dozen dollars to the cost of a new car. My Dodge van is a ’66 model, which means it was the last year for the single-circuit brakes that gave our forefathers their moral strength (though not as much strength as their forefathers, who relied on mechanical brake actuation instead of hydraulics), and a lifetime steeped in Naderite propaganda has convinced me that I’m better off with some margin of hydraulic safety. Upgrade time!

Rocket Surgery Racing Renault 4CV team captain Rich gave me a coupon for brake-line assistance for my birthday, so I decided it was time to take him up on the offer.

The new 1967-grade dual-circuit master cylinder cost well under 50 bucks, and new brake hoses plus some line and fittings didn’t add much more to the cost of the project. This would be an all-sweat deal.

More sweat than we expected, because the A100’s forward-control setup necessitates a funky linkage-and-backward-mounted-master system. The master cylinder, which is actuated by a system of rods and pivots that appear to have been adapted from a piece of 1897 mining equipment, is located directly below the driver’s seat.

I’d assumed that Chrysler, once all their lobbyists had failed to fend off the dual-circuit brake demands of the US government— headed by arch-liberal integrationist Lyndon Johnson at the time, as if I needed to spell that out for you— would have found some cheap, bolt-in way of installing the slightly longer dual-circuit master cylinder, but it turned out that the ’66 master cylinder’s tack-welded-in-place splash shield didn’t have room for the ’67-and-up components.

So, the Sawzall had to be brought into play. This involved jarring loose 45 years of built-up crud, not to mention the opportunity to slice important stuff ranging from the wiring harness to the throttle cable.

Hacking this piece of sheet metal away means that some air destined for the radiator will slip past, so I might fabricate a replacement that fits the new master. I’ll see what happens when summer heat comes along; for now, the engine runs quite cool with this small opening next to the radiator.

With the help of a $2.99 tube bender and some coat-hanger wire as a template, Rich starts work on the replacement brake lines.

I’ve never been able to do a double flare correctly, in spite of several very frustrating afternoons spent trying to do so in the past, so here’s the part I was especially glad to have Rich take on.

Modifying the plumbing was pretty straightforward; plug one port on the original four-way tee that once split the line from the master cylinder into one line to each front corner and one to the rears, using it for the front circuit only. Add another tee to send pressure to the rear brakes and signal pressure to the hydraulically-actuated brake light switch.

Bench-bleeding the new master cylinder.

To add fluid to the master cylinder in an A100, you must remove an access panel located on the floor just in front of the driver’s seat. Naturally, the access panel doesn’t quite fit the larger dual-circuit master cylinder, so a funnel must be used to get fluid to the rear reservoir. This process got brake fluid all over everything beneath, which made finding leaks a real challenge.

I didn’t trust the parked-for-12-years brake hoses, so I sprang for new ones all the way around.

After some bleeding, the new setup works fine. I’ll probably convert to front discs at some point, but for now I’m satisfied with drums that are less likely to fail. Anybody want to buy a genuine single-circuit A100 master cylinder?