I'm helping a widow to fix the brakes. Her husband just passed away and have restored the brakes. But, the brake pedal sticks. I think the leather seal lacks lubrication. The manual says "vacuum cylinder oil".

What is "vacuum cylinder oil"?

People are using neatfoot oil, ATF, shock absorber oil, mineral oil etc.

What lubrication shall I use for the wick and leather seal in the 1955 mercury Bendix Treadle Vac Power Brake Booster?

1955 Mercury

I use silicone grease on my Bendix. Worked perfectly.

Drives: Mercury Montclair 1957th

www.mercury1957.com