When I say the Girling reservoirs are a PITA, I mean it. It took me a couple or three or more years before a combination of
Seal-All, Dorman rubber stoppers under the lid, and then custom cut top of the can "gaskets" (which you can see in my photo above and that start to look really nice after they sop up the brake fluid for a season or two) are actually made of orange
Sham-Wow. Yep, the kids gave me a box of
Sham-Wow for Christmas one year and that stuff works and looks great after it's been on the cans for a while. But, if I had to replace those reservoirs now, I'd use the new Moss Motors can here:
https://mossmotors.com/tank-assembly-single-supply They look like they would hold up much better. Oh, and I always use the
BLUE Ate SuperBlue Brake Fluid. You can't buy it in the states anymore, you have to order it from overseas. It makes identifying brake/clutch fluid puddles quick and easy.