The MC "washer" as you call it is similar to the one on the clutch MC. It is domed and held in with the clip. The dome should be outwards so the shaped end of the pushrod is held central in the cup. If you put in on the wrong way round, the pushrod and therefore the piston, cannot return far enough to uncover the hole where the brake fluid returns into the pot. Ergo you pump the fluid into the brake system but it has no way of coming back when you release the brake. Same thing with the clutch. Lucky to have decent bumpers. As you say, they cost an arm and a leg. Even more to get them replated properly.
I didn’t put it on backwards, I used a Mazda FB RX7 master cylinder that wasn’t designed to have a captive pushrod. Having the pushrod retainer under the circlip pushed the piston far enough down in the bore that it covered up the return port for the front circuit.
Enjoyed the video. Where did you find those nice shiny and straight bumpers? I've struggled with that for my Amazon. I'm showing my age here, but I once worked on a 122S with the fuel starvation issues yours has. It was over 40 years ago at the import car repair shop near Emory University that I worked at fixing the cars the local dealer could not fix. A vacuum gauge before the fuel pump showed the pump drawing a vacuum when the car intermittantly suffered it's power loss. Problem turned out to be a ball of solder rolling around in the bottom of the fuel tank. Every now and then it would roll over to the fuel pickup, block the fuel flow, and the engine would die. Then it would drop back down and roll away until next time....
I got super lucky, the car came with the bumpers, but not the brackets. Tracking those down was a bit of a struggle. If you're doing a restoration, VP Autoparts sells new manufacture bumpers, but they're awfully spendy. Appreciate the comment!
