'57 Brake Master Cylinder

[Doc Love]

First I would like to thank you all for your help with our project, the ignition switch problem is solved.

Today we have an issue with the master cylinder (new from MAC's Auto Parts) and the brake pedal push rod.

The main piston of the master cylinder is hollow, that is I can see the back of the black rubber seal on the face of the piston. I've never seen a master cylinder that was not solid on the face. Pic 1

The push rod is a smaller diameter than the hole in the master cylinder piston, so small it pushes up against the rubber seal. The hole of the piston has a shoulder machined into it that looks like the rod is supposed to press against it, but the rod is so small it passes right by.

The rod looks like it needs some kind of fitting on the end but the old M/C did not have one and it has a blind hole so the rod moves the whole piston without any problems.

Any advice on this?

[Jimz Bird]

Hi Doc,

Glad the Ignition is good for you now.

Are you upgrading to disc brakes? Is this a stock MC?

I looked on MAC's and he lists the part # 1955-1957 B5A-2140-B which is correct.

Is there a part # on the MC? It is possible that you were sent the wrong one, which is my first thought.

All MC from 52-56 are the same as the 55-57 bird. (See the Interchange list attached)

There is no difference between Manual and Power brakes MC as the booster is "after" the MC so the same MC is used.

I have also attached a pic of a MC from Rockauto. That should be more like the one you have I believe.

Also an exploded view of the 55-57 MC.

Check with MAC's to be sure they sent you the right one.

BTW the 9.30 by the interchange # is the cost of the part when the interchange list was published. 1965 I think it was.

[paul274854]

There is a small piece that goes on the end of the rod. Part # 2142 in the CASCO catalog. The old one may be in your old master cylinder, tough to get out if it is.

[Jimz Bird]

Good "tip" Paul - thanks.

Here is the exploded from the CASCO catalog. It has the 2142 marked. Just as Paul said - it goes on the end of the pushrod. It looks to me as it would then fit in the tapered hole in the MC.

Pg 10 in the catalog.
2142 Plastic Tip - Master Cylinder Push Rod....................7.09

Six bucks at Tee Bird Products in PA. Probably others also.

http://www.tee-bird.com/catalog_product_detailed.cfm?id=11789