I assume you're referring to the rear brake master cylinder. Yes, you need to ensure that it does not come out. But the upshot is that unless you pull directly on it, it's not likely to come apart. There is a part of me however that questions the sensibility of spending the money on powdercoating for crappy cast items when the money would be better spent on better looking, better working, more sturdy, and crashworthy ones from Woodcraft, CRG, and many others.