Master Cylinder swap question
 

I plan on replacing my '93 NA M.C. and booster for the 15/16in. MC and booster from a 2005 MSM, both for the firmer pedal, and increased flow for future Wilwood caliper swap. Question is: Both the NA, and my 2002 NB MC's have two outlet ports for the front brakes; one directly to the driver's side brake, and the second into the proportioning valve mounted on the booster. The MSM M.C. only has a single front outlet port: does the MSM have a inline "T" here?, or is it the ABS routing that accounts for it. If anyone here has a photo of their MSM that will enlighten me I'd appreciate it. It looks like by rotating the pro. valve 90 deg. it will match up with the existing lines on the NA quire easily. I think I just need to "T" my single outlet to retain the stock function / routing, true?
https://cimg4.ibsrv.net/gimg/www.mia...801f87683c.jpg
'93 NA's dual outlets
https://cimg9.ibsrv.net/gimg/www.mia...d21e2d9090.jpg
Same with the NB
https://cimg4.ibsrv.net/gimg/www.mia...c020a78943.jpg
Single front outlet port on MC I want to use

Looks like it will be a T, M10-1 threads.

Just looked at my MSM. It looks just like your last picture.

Can you tell me where the single outlet from the MC front goes? It will be to the front calipers, but I'm guessing it goes first to the ABS block, and then splits to feed both front calip's? I plan on using it to feed a T 3-way, so I can match up with the lines in my NA, but as I don't have access to a MSM, and my shop manual doesn't show anything, I'm kind of guessing. Thanks for your reply!

I assume your NA doesn't have ABS and that accounts for the complication; ABS has a different port setup. I don't remember the exact details, but there's a lengthy thread on miata.net started by Keith Tanner which discusses master/booster compatibility.

When I got my MSM master/booster for my non-ABS NB I found someone who was looking for an ABS 15/16" master and we traded. Failing that, I'd probably just buy the appropriate non-ABS master to avoid having to rejigger things, as they're fairly cheap.

The swap was well worth it, although I think a bigger 1" master would've been even better. But then you're back to dealing with an ABS 929 master cylinder.

Edit to add that this brake line T fitting may be relevant to your interests: Flyin' Miata

Yup, Pretty sure your are right with the ABS comment; both my NA, and NB (pictured) have the two ports at the front of the MC to feed the front calipers, the the MCM MC I want to use has the single. Because it looks almost new, I will try to use it, and have found a 3-way female inverted flare M10 T I plan on T-ing the single port, and then routing like the non-ABS method. I'll look up the FM fitting you suggest, and appreciate the info!

TalkingPie: I have read thru Keith's great post on MC's which is where the info came that got me thinking about the swap. The FM fitting is similar to what I have coming in the mail. Thanks again!

There are 2 outlets from the MC, not a single. One for the front and one for the rear.
https://cimg4.ibsrv.net/gimg/www.mia...b28f1e069c.jpg


I want to go with a bigger MC on my MSM because the previous owner put Willwoods on the front. Regardless here is a pix of what I have if that helps.

Also I have no idea why the booster is red. I am guessing the PO painted it at some point after the original failed?

https://cimg6.ibsrv.net/gimg/www.mia...348f047e66.jpg
https://cimg7.ibsrv.net/gimg/www.mia...c5cb8d8fae.jpg

Thanks for the great photos. My comment about the "single" outlet referred to the single front outlet, as opposed to most Miata MC's having a pair of front outlet ports, (and the rear line, of course). The non-ABS MC's 2 front ports send one leg down to the driver's side caliper, and the second goes into the proportioning valve, but as your photos show, (and mine) the MSM MC just has the single front port. I have found a nice 3 way T, with the correct flare size to create my own second port. It was only $8. https://www.ebay.com/itm/Metric-Tee-...72.m2749.l2649 and seems well made. Thanks for the pic's!