Another master cylinder question

[DART66GT]

I just opened my MC on the Lancer for the first time getting ready to bleed the new brakes. The rubber seal/bladder looked like pic #1 . I messed with it a little and got it to look like pic 2 and 3. Does anyone know which way it should sit? It's the drum/drum MC in the bottom pic.
Thanks

 

[goldduster318]

The bottom picture is what I've always seen on new condition parts. If it needs to move it will do so.

 

[Dana67Dart]

The #3 photo is correct. The #1 photo is what happens as the fluid level drops. Whenever I pull the cover I push the bellows back in, like in photo #3

 

[DART66GT]

Thanks for the replies. Ive never seen one pushed out like that.

 

[Tooljunkie]

It serves as a bladder to keep air away from the fluid. As fluid drops the bladder part stays with fluid. instead of it being open to the air. Brake fluid absirbs moisture from the air.