1950 Ford Custom Brake Master Cylinder

[glennpm]

Originally Posted by DNLs1930

Thanks for the link to a really good video on the operation.

So the return bypass fluid would increase the pressure in the reservoir but the cap it is vented so it can't build up; makes sense.

I will keep checking the fluid level and see what happens with the new seal on the cap...

Yes that's correct the cap vent prevents pressure buildup from the pressurized brake fluid squirts out the bypass hole.