I went ahead and ordered the 1118 adapter and it worked. When I first test fit it, it wouldn't hold pressure. I could hear a slow, but steady air leak where the adapter screwed onto the master cylinder even with the thicker gasket. So I was planning to just keep pumping it up. But later when I actually did the job, it held pressure. It might be that I didn't have it fully screwed on the first time or maybe a little bit of brake fluid at the mating point sealed it. Whatever the case, 1118 fit and held pressure up to 15 psi for me.Motive's application guide now says the 1118 adapter has been updated to fit 1.8" openings. Has anyone tried it?