Identifying leaking Master Cylinder

MGM · #1 (**permalink**) 03-28-2021, 06:11 PM

Literally the day before my first drive EVER with the car, I noticed a pool of brake fluid on the garage floor. Leaking between the master and the booster.
That thing is hard to get at- had to remove the exhaust on the drivers side.
Anyway- there are no notes from the build log as to what it’s from. One note says to possibly find a MC and booster from a V8 mustang.
Is anyone able to identify this from the pictures? I’ve googled the numbers on the id plate on the booster but no luck. Thought if I knew the booster I could identify the master cylinder.

I need to know what it’s out of to either replace it or find a rebuild kit. I guess I’ll have to wait on that first drive. 😔

Thank you guys for all the help!

kitcarbp · #2 (**permalink**) 03-28-2021, 07:10 PM

I had to play the same game for my car. “Name that MC”. Took me a few days to figure mine out.

I used the NAPA website. They have great pictures for the master cylinders and specs too. Yours could be from a 74 Mustang or close to it. It would be best for you to measure the piston bore on your unit to help you ID it exactly. The Mustang2 used 15/16” bore it says. Look at this unit here:

https://www.napaonline.com/en/p/NMAM2139

MGM · #3 (**permalink**) 03-28-2021, 07:56 PM

KitCarBP, thank you! I’ll go measure it now.
From looking at pictures, my guess is Mii master cylinder. And hey- $50 on Amazon for a new one. I’ll go check on that bore size. Cheers

MGM · #4 (**permalink**) 03-28-2021, 08:11 PM

Yup, 15/16th’s. I’ll give the Amazon one a shot. Really looking forward to getting this on the road

kitcarbp · #5 (**permalink**) 03-28-2021, 08:13 PM

If you must buy on Amazon, please make sure you buy a name brand when it comes to braking components. Check Rockauto.com too. I trust them way more than Amazon. Good luck with your search!

MGM · #6 (**permalink**) 03-28-2021, 08:24 PM

Oh for sure. Good advice. I normally go to the parts store in town to support the local business, but had an Amazon gift card from my b-day to use up.

MaSnaka · #7 (**permalink**) 03-28-2021, 08:45 PM

MGM,
It matters if you have drum or disc brakes in the rear. I used the master from CPP. I believe it replaces a MC from a corvette but not sure. Disc/disc.15/16" I don't have my catalog anymore with the part number.

John

MGM · #8 (**permalink**) 03-28-2021, 09:52 PM

Hey John,
Yes, that sounds right. The one I ordered said front disc rear drum power booster (Mii), so hopefully it works for me. That’s what I currently have. Need to upgrade to rear discs eventually, but I’ll see how she stops first 😊
I wish there was a master list of every part on this car! It would make this so much easier. I’ll be sure to put one together when I’m done.

74proii · #9 (**permalink**) 03-28-2021, 10:21 PM

Quote:

Originally Posted by MGM

I wish there was a master list of every part on this car! It would make this so much easier. I’ll be sure to put one together when I’m done.

That's why mine will have a engraved list on a plate in the trunk. That way down the road you can actually source replacement parts, vice the guess this part game.