Another brake question

[CalsonicGTR]

I installed the new master cylinder today, but it got dark so I couldn't do a brake bleed. When I went to press the pedal the first time with the car off, however, there is no pressure. It goes straight to the floor. Did I mess up my brake booster or is it supposed to feel like that before the first bleed?

 

[p5150]

Your brake booster is just a big diaphragm that uses engine vacuum to give you a bit of mechanical advantage and make it easier to press the brake. I think its fine.

Before I install a master cylinder I will do a bench bleed but you will probably be OK. Just manually pull the brake pedal back up from the floor. Ensure that you are always keeping the reservoir full of fluid so that you dont pump air into the system.

 

[Clip]

just bleed normally and watch the fluid level, itll take a while to build some pressure while bleeding at all four corners.