How is air getting into my lines?

TrailBeast said
Would you be willing to double as my line lock? :D
I can yell pretty loud.

You think one tire will hold; I cant reach both sides. I work for Pepsi's

NEVER pinch hydraulic hose. Even though brake hose could be classed as low or medium pressure hydraulic hose; you can damage the inner liner with pinching or kinking. This "shortcut" is only done by less-than-stellar or un-informed mechanics.

RedFish said
I wouldn't kink a high pressure fluid line much less pinch it with pliers.

Guys; special tool; Been doing it many decades no comebacks, relax . I didn't say clamp it off with a Visegrips. Teachers teach all kinds of stuff, some total BS,probably to protect their own asses from newbies using Visegrips. I can only imagine.
But since you mention it, this method is not acceptable on high-performance type hoses which may have non-rubber inner-liners; you know,the braided stuff; which I totally love, and highly recommend.