Brakes: Lubrication 1955-57 Brake Power Unit Lubrication

[jnfweber]

I have been driving and restoring my 1957 President Classic for four years. I have replaced the leaking right front wheel cylinder and bled the system. Even before this, and still today, it takes a 2nd push on the pedal to get the full power of the brakes, enough to skid the tires. It does stop well without hard pressure, but there should not be excess pedal play to begin with. The master cylinder is full with DOT 3 fluid. Maybe I need to re-bleed the system, as there could be a small amount of residual air in the line, but this is a pain in the a** requiring a lot of time by myself, or less with an assistant. On page 22 of the brake section of the 1956-57 shop manual is a paragraph labeled "LUBRICATION" stating that one ounce of Power Brake Cylinder Oil should be added to the unit every year or 20,000 miles. I doubt if I have driven it 2,000 miles since I have owned it, and I have heard that "neatsfoot oil" could be used on the unit. Question: Where does one add said oil? Members of my local SDC chapter have told me that the "grease zerks" on the top of the unit (2) are for excess brake fluid to exit. Suggestions and advice will be considered, and if appropriate, acted upon. Thanks.

[RadioRoy]

There should be a square-topped pipe plug on the large diameter vacuum drum of the booster. Remove that and put the neatsfoot oil in.

[Mark Klinger]

The two "grease zerks" are for bleeding the Hydrovac, just like the wheel cylinders.

[jnfweber]

There should be a square-topped pipe plug on the large diameter vacuum drum of the booster. Remove that and put the neatsfoot oil in.

I'll look for that. And try to find some neatsfoot oil. Local shoe repair shop or amazon.com.

[RadioRoy]

I'll look for that. And try to find some neatsfoot oil. Local shoe repair shop or amazon.com.

The plug looks like it is in your picture (was that picture there originally?) adjacent to the two small studs on the starter solenoid.

A well stocked hardware store should have neatsfoot oil.

[Dwain G.]

Yes, the square-headed plug. Your photo is almost identical to the one in the shop manual. Very handsome car too!

[ddub]

The oil should be available at any place that caters to horse owners. Must be some of those in Montana.

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[studegary]

I will offer a caution. Only use neatsfoot oil in the unit if the unit has not been rebuilt using modern materials.
It sounds like you have not bled the power unit. Do this.

[Mark Klinger]

I will offer a caution. Only use neatsfoot oil in the unit if the unit has not been rebuilt using modern materials.
It sounds like you have not bled the power unit. Do this.

Gary If you do add the neatsfoot oil to a rebuilt unit what are the potential problems?

[jnfweber]

I will offer a caution. Only use neatsfoot oil in the unit if the unit has not been rebuilt using modern materials.
It sounds like you have not bled the power unit. Do this.

I have read how to bleed the power unit in my shop manual. There is plenty of fluid in the master cylinder, and I will try to get my wife to assist pushing the pedal while I bleed the two screws in the sequence recommended. I will hold off buying or adding neatsfoot oil and, as our President says, "Let's see what happens."

[studegary]

Gary If you do add the neatsfoot oil to a rebuilt unit what are the potential problems?

I believe that it will cause the diaphragm to swell and/or deteriorate.