Do I need to bench bleed a brake master cylinder to install?

[ajf3]

Getting ready to replace mine...

Some say bench bleeding is necessary, others say no... what are are the plusses/minuses of doing it or not?

Thanks!

[stereoking15]

pluses your brakes will work , minuses you will more than likely crash into a fiery death , how you do it is that you will fill it with dot 3-5 not 5 if running abs brake fluid and screw a brakeline fitting into your many outgoing lines and put the lines back into the resevoir and finally upon install take them out and do the normal recommended brake bleeding procedure,(note abs may be different) if all else fails read the manual

[mitmaks]

yes you want to bleed it, after changing fluid too.

[neutral]

Have never done bench bleeding and can't figure how that would eliminate the need to bleed after install so not sure what good bench bleeding would do. Have always bled after the new master cyl. is installed. Seems consistent with the shop manual instructions too... page P-7.

[PATDIESEL]

No bench bleeding necesary. You can jusr bleed it after install. Just make sure that you bleed it completely b/c there is no fluid and there will be alot of air to get out.

[ajf3]

I guess my question is more, if I bleed the brakes normally (at the wheels) does that bleed the MC too?

I don't have extra flare fittings/lines to feed back in & wanted to see if it's necessary that I go buy them, or if I could just bleed it out via the wheel bleeders?


Thx!

[illicitQ]

3 answers:
1. YES the master cylinder must be bled
2. NO the MC doesn't need to be bench bled. you can mount it then bleed the MC.
3. NO, bleeding the MC through the brakes will NOT work. you must bleed the MC separately from the brakes.