Brake servo test?

[Sheepdip]

I had issues with my brakes going soft. since everything was changed except the brake booster, I swapped it out for a spare. in my case the booster seemed to work at times but not others.

Mine doesn't feel soft, more slightly hard but stops ok

[Sheepdip]

You could try pulling the vacuum pipe off the engine end & sucking on the pipe, see if it holds any vaccum.

The servo is not an easy thing to split / reassemble the two halves.

Pulled pipe from manifold and tried sucking, could hear a clicking which I guess is one way valve but couldn't notice any vacuum build up no matter how much sucking! Thinking again will run engine to hopefully build vacuum then pull pipe and try to suck again.