I use a depth gauge, it's worked just fine on every one. Most don't even need to be adjusted.

 

I just hope this fixes the brakes. These 5 mile trips are not getting me anywhere!

 

If the pushrod is adjusted too short it'll have more freeplay at the pedal, too long and it hangs up the brakes.

 

When the pistons inside the master are in the full released position, the primary pressure cup should sit behind the little holes in the bottom of the reservoir, this releases pressure inside the system. If it's assembled improperly, or an o-ring rolls off the back of the rear piston and gets trapped between it and the plug in the back of the master, they wont pass the holes and wind up holding pressure. They get worse as you drive and heat the brakes because the brake fluid is expanding, but has no place to go.

 

Makes sense. Think I'll make sure mine is a little too short vs. too long, if anything.