Always use a box end wrench to avoid rounding the bleeder bolts , whacking them dead on with a 32 Oz. ballpien hammer ofttimes shocks the rusty ones loose , avoiding the snapping off bit .
You should put a snug fitting hose over the bleeder nipple and dunk the other end in a clear jar (Pepsi bottle etc.) with 1/2" of brake fluid in it , then you can clearly see not only the bubbles but also when dirty brake fluid stops coming out the hose . I always bleed untill I get clean fluid after the bubbles stop .
Don't forget to safely prop up the truck on jack stands .
You'll need a quart or more of fresh fluid , NEVER
put the old fluid back in the master cylinder ! .
