Girling master cylinder ID

[Mike B]

I may be missing the obvious but can someone tell me what the bore diameter is in this master cylinder?

[Garey Guzman]

Looks like it says 3/4 (after Girling). Was it on the front?

[teamwisconsin]

I think that it says 3/4 right there BUT sometimes the lettering on the side of Girling master cyl’s is tough to read.

[Mike B]

It's very hard to read but now that you point it out, I can see where that might say 3/4. Must have been toward the end of that mold's life. Thank you!

[Bob Clark]

Look 180 degrees and the same info should be on the other side also. Might be easier to read.

[Mike B]

Look 180 degrees and the same info should be on the other side also. Might be easier to read.

It was actually worse!

[Bob Clark]

Figures..You can always take it apart and measure the bore.

[Mike B]

Figures..You can always take it apart and measure the bore.

It is coming apart but I wanted to have the right rebuild kit on hand so I can put it back together right away. Order coming your way soon!

[kea]

3/4 inch.

[tstrong]

The 3/4 is difficult to read on all the cylinders I have ever seen. The good news is the other common sizes 5/8 and .70 are much clearer so if it doesn’t say one of those chances are pretty good it is 3/4. The one pictured is definitely 3/4 in my opinion. Todd

[scorp997]

Original Girling master cylinders have another casting mark that denotes the diameter.. if the cylinder has a single “ring” cast around it (like the one in question) it is a 3/4”, if it has 2 “rings” it is a .70”, and if it has no cast rings it is a 5/8”.

sometimes the .70 has a full ring and the second is a second ridge that doesn’t go completely around the cylinder.

Lockheed had something similar, I don’t use them so I don’t have the specifics.

hope that helps someone in the future.