I had heard it rumored that a master cylinder from an early 80's Mazda RX7 could be used to upgrade to dual circuit brakes in place of the Volvo unit.

Rock Auto had the unit in question (for use with rear drum brake cars)on closeout for $28 so I figured I'd give it a shot, since it included the reservoir and low fluid switch. BECK/ARNLEY Part # 0728107.



I got the unit and gave it a trial fit. The mounting pattern was very, very close to the Volvo. I had to overbore the mounting holes slightly and shorted the top bolt a bit, but it bolts right up with those small changes made.





Now, for the inevitable questions.

1) Initially, I was planning on using this MC in a single circuit configuration. I believe that some 68 122s came this way (with the dual circuit MC, but plumbed for singles). Reason being is I am still waiting on some extra tee's and fitting to show up, but would like to take the car to a show before then. Is this possible? Which port (front or rear) is for the rear circuit?

2) The pushrod on the RX7 MC is the style that is not retained in the unit by a circlip or physical stop like the Volvo unit. What is the best/safest way to use this MC with the volvo brake arm setup?