I mocked up all three brake master cylinders - 15/16", 1" and 1 1/16" - on a '98 booster. They all fit fine. If I could find a 1" BMC for a Sport - without taking the one off my '03 - I'd try that, too. Brake master cylinders are hard to get here without ordering it and at this point its not worth the time to mess with. IMHO, if someone needs a 1" BMC for a '90s something they could just as easily use the 3000GT non-ABS BMC.

Pictured below is the Mitsubishi tool used to measure and set the brake booster push rod for the master cylinder. It is WAY easier to use than a block and ruler.

I checked the factory setting on the 1" BMC that came on the booster. It was actually off by just a hair, but it was noticeable. I checked the 1 1/16" MC and it was almost dead on - maybe 1/4 turn. Then I checked the Gen 1 Sport BMC and it looked to be off by about what I came up with by doing the math. I'm guessing maybe two turns.

The only other thing I found that was noteworthy was the instructions in the FSMs. They say to use a tiny 1/4" ratchet and deep socket (or extension) to turn the adjuster while holding the base inside the booster with an angle nosed long needle-nose pliers. Someone might have some other tool that might work but I don't. Glad I bought a pair a while back.

Didn't get a chance to mount the new BMC on the big Sport this weekend. I decided that before pulling everything off and swapping BMCs, I wanted to take measurements of fr/rr brake line pressure at the caliper so I know where I'm starting from especially if I have to install an adjustable proportioning valve. Since I'll be replacing the OEM valve entirely, I'd like to know what OEM looks like so I can set the new valve to something I know works. Anyway, didn't have the measuring tools 'till today and forgot the MC bleeder kit at the office Fri. Sigh.

Mitsubishi Brake Booster Push-rod Adjustment Tool MB991714-01







1998 Mitsubishi 3000GT N/A non-ABS Brake Booster






Edward