What chemical would you soak a master cyl in?

Dana67Dart said

I have a master cyl that was well sealed for 40 plus years.

The inside of the reservoirs are not rusty but is kind of solid with dried brake fluid.

Right now I'm just trying to get the crusty solid gunk out.

Chemical thoughts


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I assume you're planning to rebuild it. I'd start by pulling it apart and hone the cylinder to see if it's rebuildable. If badly pitted and you just have to reuse it for some reason, have it stainless sleeved, rebuild it, and then use DOT 5 fluid from now on. If it's not badly pitted, soak in Evaporust, rebuild kit, and DOT 5.