73 Master Cylinder Confusion

[John M.]

All,

I am confused by the 1973 judging manual which states that a 1973 power brake master cylinder (5480346) is stamped with a "TG". Also are all master cylinders date coded on the brake line boss? I have seen several 5480346 master cylinders that have no date code in this area.

Lastly the judging manual states that a master cylinder Julian date starts with the year (for example 2237 for 237th day of 1972) is this correct?

As always thanks for the help!

John

[Harmon C.]

Re: 73 Master Cylinder Confusion

Their is no (TG) stamped on a 73 master cylinder only the tag on the bail. The date coding is correct.

[Russ S.]

Re: 73 Master Cylinder Confusion

The "TG" is on a tag that is placed around the bail wire as well as stamped on the machined area. Both of my 73s are the same configuration with one being a sept 72 build and the other an April 30th 73 build with exception that the Sept build master cylinder has a machined area on the forward end of the MC but with no stampings on it. Yes they are all dated.

PS One other difference I noticed is that the casting number on the sept 72 reads from rear forward and the April car reads from front to back. I can't post a picture as I haven't learned to do that. I can email you one.

[John M.]

Re: 73 Master Cylinder Confusion

Russ,

Is there anyway you could post a picture of that "TG" stamping?

Thanks,
John

[Harmon C.]

Re: 73 Master Cylinder Confusion

That (TG) was in small letters on the threaded boss and it was not stamped on the front in large numbers as in prior years.

[John M.]

Re: 73 Master Cylinder Confusion

Does the master cylinder still have the machined thumb nail in the front or did the machined area disappear for 73

[Harmon C.]

Re: 73 Master Cylinder Confusion

It was not machined.

[Russ S.]

Re: 73 Master Cylinder Confusion

My Sept 72 build has the machined area with out any thing stamped there. My April 73 doesn't have the area machined. Both are original.

[John M.]

Re: 73 Master Cylinder Confusion

All,

Russ was kind enough to send some pictures of his two 1973 master cylinders. The first 2 pictures are of an early 73 car (Sept 72) which show the machined area in front of the master cylinder unstamped and the forward brake line boss stamped with a "TG" prefix. The third picture shows an April 73 car with the same "TG" prefix on the brake line boss (this master cylinder has no machined area in the front of the master cylinder). Perhaps this demonstrates a transition period in 73 master cylinders?

MasterCylinder1.jpgMasterCylinder1_machined.jpgMasterCylinder2.jpg

My confusion with the judging manual was twofold. First it states there was no machined area in the front of the master cylinder (by the posted pics this is only partly true. Second it states that the date code is "preceeded by a letter and a digit which may represent the molding casting number". In the case of power brake 73s, the prefix is "TG" as shown in the pics.

Thanks to Russ for sharing the info/pics.

Regards,
John