master cylinder question

[RT999]

I have a 1970 challenger r/t with manual brakes. i am needing to replace the master cylinder. Do i have to remove the rod before unbolting it from the firewall, or will it come out by just removing from the firewall.
Thanks for any help 
Tom

[JH27N0B]

You have to remove the whole master cylinder/push rod assembly together.
The push rod is retained by a rubber retaining ring that is sort of a collar.  Clamp the pushrod in a vise and tap on the master cylinder flange with a hammer, and it will come loose, after some degree of persuasion.
Master cylinder kits usually come with a new rubber retainer to reassemble the pushrod into the piston. Some people make their own cutting a piece off a appropriate diameter hose.

[RT999]

  many thanks

[Katfish]

Sometimes it can be a bear separating the push rod from MC when removed together.
I find it easier to unbolt MC and pry it off with push rod still connected to pedal.

[1 Wild R/T]

You have to remove the whole master cylinder/push rod assembly together.
The push rod is retained by a rubber retaining ring that is sort of a collar.  Clamp the pushrod in a vise and tap on the master cylinder flange with a hammer, and it will come loose, after some degree of persuasion.
Master cylinder kits usually come with a new rubber retainer to reassemble the pushrod into the piston. Some people make their own cutting a piece off a appropriate diameter hose.

I've persuaded till I couldn't persuade no more & that pushrod can be damn happy right where it is....

If you have a floor jack with a removable saddle grab it & remove the saddle, this should leave a round hole, drop the M/C on the jack with the pushrod through the hole & extending through the bottom of the jack.... Now pass a steel rod through the bolt hole in the pushrod, this should pass across the side plates of the jack...... Operate the jack till the pushrod separates from the M/C.... Crack a beer....

[mopar jack]

before I pull the master cylinder I loosen the brake light switch and swing it out of the way and lift up on the brake  pedal. That removes the rod with little effort.

[RT999]

Thanks to all who sent suggestions 
i ended up using my floor jack.