First time using a vacuum bleeder (harbor freight mity-vac style) on my SMT with ABS. I found the recommendation for thread sealing after the fact. I just did the rear but so much air was being pulled through the threads that I had to pump the vacuum pump constantly. The fluid would just sputter through the tube. I couldn't judge its color so I stopped after about 2.5 oz. Did I just introduce air into the system? So I can use the normal white PTFE tape sold in the plumbing dept? What's going to happen when I remove the bleeder screw to apply the tape? Much fluid loss? Should the reservoir cap be on or off?