Leak between Master Cylinder and Brake booster

[aevansgatech]

Came upon a frustrating issue while bleeding my brakes.

I'm losing brake fluid and the only spot I can really see it start to pool is between the brake master cylinder and the brake booster. I never had it off, I only replaced the feed lines from the reservoir, so it's hard to imagine what is going wrong. Is there a gasket in between the master cylinder and the booster which may be compromised?

On top of that, I am able to successfully bleed the brakes (calipers) and the pedal is firm, so it seems to be an issue on the feed side.

[ORFORD2004]

Is there a gasket in between the master cylinder and the booster which may be compromised?

No, change your MC.

[nelsonj]

After you change your master cylinder, only then will you learn the true joy of bleeding, really bleeding, your breaks. There must be a better way than what I went through...

[aevansgatech]

thanks guys, somehow my MC went bad over the winger then

is it worth getting a power brake bleeder? I'm assuming that takes care of air in the MC and the lines

[RRoller123]

I am just about to undertake this too, MC including the booster. Is there a trick to getting the MC started in the bleeding process, without making a bloody mess everywhere?

[DieselSpider]

You can bench bleed the master cylinder however that is more difficult when they do not have a built in reservoir. Myself I finally a few years ago I did something I should have done 45 years ago and that was pickup a MityVac Vacuum Bleeder. Best $29 I ever spent.

[aevansgatech]

You can bench bleed the master cylinder however that is more difficult when they do not have a built in reservoir. Myself I finally a few years ago I did something I should have done 45 years ago and that was pickup a MityVac Vacuum Bleeder. Best $29 I ever spent.

Do you use the vacuum bleeder at the caliper bleed screws or do you need to use the vacuum bleeder on the MC first?

I don't understand how to connect to the MC outlet ports when the MC is out of the vehicle.

[DieselSpider]

You can bench bleed the master cylinder however that is more difficult when they do not have a built in reservoir. Myself I finally a few years ago I did something I should have done 45 years ago and that was pickup a MityVac Vacuum Bleeder. Best $29 I ever spent.

Do you use the vacuum bleeder at the caliper bleed screws or do you need to use the vacuum bleeder on the MC first?

I don't understand how to connect to the MC outlet ports when the MC is out of the vehicle.

There are plenty of adapters that came with the MityVac Kit however with a vacuum bleeder you can skip the bench bleeding of the master cylinder. On the Spider bench bleeding is a bit more difficult since the reservoir is mounted on the fire wall.