Bench Bleeding a C1 Master Cylinder

[Christopher R.]

Preparing to replace the brake master cylinder in my 1962. Is it necessary to bench bleed the master cylinder before I install it? I understand that the whole system will need bleeding after changing the master cylinder. The system has DOT-5 fluid (silicone), if that makes any difference.

[David B.]

Re: Bench Bleeding a C1 Master Cylinder

Chris,
Bench bleeding makes it easier, although it is not absolutely necessary. It will reduce the amount of air that gets pumped into the lines and thereby makes the bleeding easier. It also reduces the amount of refilling of the master cylinder. Remember to start your bleeding with the right rear wheel cylinder (most remote from master cylinder) and work your way back to left front last. I used silicone on my C-1, along with new stainless lines. If you are using stainless threaded fittings, they must be very tight to avoid leaks compared with regular fittings, as they are not as malleable. If using existing lines, make sure that the non-silicone fluid is completely removed/flushed. New rubber hoses are recommended for the 3 spots, as it reduces the slight spongy feeling that some owners report with silicone fluid. When done, it will be great! My C-1 braking system is excellent - and doesn't feel spongy at all.
Dave B.