As a lot of Mitsubishi guys know, Mitsubishis and Hyundais share a lot of parts. When Hyundai was just getting started in the '80s, they licensed a lot of designs from Mitsubishi. Well, one of them was the clutch master cylinder from the Starquest; if you look up the interchange, you'll see that the '89-'93 Hyundai Sonata uses the exact same part as a Starquest. Unlike Mitsubishi, Hyundai kept the same design well into the '90s, and made improvements; the '98 Sonata version has a solid clevis. So, you can get a brand new master cylinder and a solid clevis at the same time, for cheap! The Hyundai part has a directly-attached reservoir though, so you need to swap the reservoir to work with the Starquest's remote setup. Everything else: the pushrod+clevis length, the clevis pin diameter, the flare and thread for the hydraulic line, and the size and spacing of the mounting holes, is the same.
Here are the two of them side-by-side:

To remove the reservoir, just loosen the clamp, warm the plastic with a heat gun, and pull it off (while wearing a glove!):

I took this picture before removing the reservoir from my Starquest master, so I could get the orientation right on the new one, using that seam in the plastic to line it up:

A look inside my original master and reservoir: SLUDGE. I had just changed the slave and bled the system with clean fluid a couple months ago, so I figured it would be clean inside. Man, was I wrong!

I flushed the OEM reservoir out with brake cleaner, warmed it with the heat gun again, pressed it on, tightened the clamp, and boom, a new Starquest master cylinder with a solid clevis. Ready to go another 32 years!

Update: I got paranoid thinking about the possibility of the reservoir leaking, so I pulled it off again and added some Permatex Anaerobic Gasket Maker to the master cylinder surface before pressing the reservoir back on and tightening down the clamp. I'm not sure it's exactly the right sealant to use for this, but it's what I had on hand, and y'know, quarantine. I noticed Mikie at MKS Motorsport includes a tube of Seal-All with his kits--that's probably the best choice. Anyway, everything is back in the car now and working great! It's been filled with brake fluid for several days now with no leaks, but I'll be keeping an eye on it.
Edited by obsolete, 29 March 2020 - 10:31 PM.