Bleeding brakes
 

I have a 1964 Chevelle with manual brakes. I am going to replace the master cylinder. When I bleed the brakes do I have to keep the cover on the master cylinder ? It would make it easier to check on the fluid level if I did not have to remove the cover all the time. I bench bled the master cylinder. Thanks.
Harvey

No you don't have to keep the cover on while bleeding. You also don't want to leave the cover off for a long period of time, off while bleeding is okay. Brake fluid will absorb moisture and that leads to rust in the system. It also lowers the boiling point of the fluid. Boiling the fluid is not likely to happen unless you're working the brakes really hard, like in pro-touring or towing a heavy load but if it does it's not a good thing. I'm not even sure if that happens with drum brakes but it can with disc brakes.

I think there is the possibility that with no cover on the brake fluid could squirt out when applying pressure to the pedal unless your going to gravity feed it.

I've never had that happen before, it may be possible, just haven't seen it myself. There's no pressure, or shouldn't be in the reservoir when pumping the peddle. A vacuum bleeder is easier anyway, then no worries and it's a one man job.

Thank you all. This will make it a little easier. Have a great day.
Harvey