Dual Circuit Master Cylinder?


Mike Israel

Hello All,

I have been given some thought to the Amphi braking
system. I have to believe that in this day an age
that a single circuit master cylinder is just plain
nuts especially given the strain on brake lines when
driving in the water. A major failure at any wheel or
line would mean the loss of ALL braking.

At Celina Hugh indicated that he would probably not
carry such items due to potential liability issues.
Still, I recall reading that many of the German Club
members have done this upgrade.

Does anyone know what the appropriate part would be
for a replacement, dual-circuit, Master Cylinder? I
imagine it is the same as is used in some model or
another of VW, Mercedes, etc..


Mike Israel
65 Amphi (white)
List/Digest Admin


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David Chapman

There are various views on this. The dual circuit cylinder from an early VW bus
(and I think some beetles) will fit but the reservoir is in the top of the
cylinder so you have to take the spare wheel out to see it and also of course
you need to change some of the pipe work. However, I think you are adding
complexity and increasing the chance of failure, also some types of failure on a
dual circuit system will still result in no brakes.

In my opinion a simple and effective upgrade is to add a buzzer which will
indicate a leak and loss of fluid. Almost all VW/Audi cars from the mid 1980s
had a simple float in the cap of the brake fluid reservoir. This fits Amphicar
perfectly, VW/Audi have this wired to turn on the parking brake warning light if
fluid level drops, much better in Amphicar is to just have a little buzzer under
the dash.

With almost any brake failure you will be able to get some braking action as
long as there is fluid in the system - this buzzer solution gives me an early

David C