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I have the 'original' (according to owner that bought the car in 1970)master cylinder off my 67. The cast part number is correct according to NCRS judging guide and at the front it is stamped DC (the car is manual brake car so that fits). However, stamped upside down on the upper left side (cast part number is on the right side) of the casting are three 'digits'. One is like an arial view of a sliced pizza followed by a D and a 5; all three are the same size and evenly spaced. My car was built early March (end 1st wk). If the stamped date on the master cylinder follows the system of A=January this would be April 5th and therefore not original. Can anyone translate the date for me? I want to have the mastercylinder rebuilt if the date is right. Thanks in advance for any help, Jim Baker.
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Re: 67 Brake Master Cylinder Date Stamp
Jim-----
The marks you describe are not dates, at all. The "sliced pizza" is actually usually referred to as a "wagon wheel" and is the logo of the old GM Central Foundry Division (now part of GM Powertrain Division).
The "D" represents the foundry identification mark. In this case, it denotes Danville, IL. This was a GM nodular/ductile iron foundry of old where many Corvette castings were manufactured. The foundry was actually located in Tilton, IL, which is a small town just west of Danville.
I don't know what the "5" represents, but I don't think it's a date. More likely it's a pattern number and irrelevant as far as restoration goes.
When these master cylinder castings have a date code, it is usually stamped in very small characters on the machined surface surrounding the forward brake line fitting. However, 1967 usually does not have dates---1968 and later usually do.In Appreciation of John Hinckley -
Re: 67 Brake Master Cylinder Date Stamp
Jim,
I have heard through this forum sometime back, that 67 Master Cylinders did not have date codes. Maybe someone else will chime in to verify this.
Jerry Fuccillo
#42179Jerry Fuccillo
1967 327/300 Convertible since 1968Comment
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Re: 67 Brake Master Cylinder Date Stamp
I think that Joe Lucia has (as usual) described the situation perfectly. The only thing I would add is that the markings you describe should probably not be described as a stamping, since they are markings in the raw casting itself. I would call them casting marks. A "stamping" implies a mark that was added after the the casting was made.
To my knowledge, 1967 master cylinders had no date stamp, but subsequent years did have them in the location that Joe describes. Those markings were made with an impact tool on the machined surface, similar to the way that the engine pad is stamped with the VIN number.Comment
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Re: 67 Brake Master Cylinder Date Stamp
Jim -
The "DC" master cylinder was used for both manual and power brakes. '67 was the only year where both manual brake and J50 power brake cars used exactly the same master cylinder - "DC", with the deep-hole rear piston. The exception was the J56 Heavy-Duty Brake master, which used the 346 casting, stamped "PG".Comment
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Re: 67 Brake Master Cylinder Date Stamp
Hello John,
Do you think this could have carried over to early 68? My Jan 68 car has a PB MC but no Booster. I was just wandering.
BillComment
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