Question on Master Brake Cylinder Codes

[gwp4]

Hello First-Gen Camaro Experts -

I'm looking for a little help decoding the numbers on my master brake cylinder (mbc) which I thought was original to the car, but now I'm not so sure.  The car was manufactured/assembled at the Norwood, Ohio plant on May 14, 1968 and is a base model 327 3-spd Camaro with manual drum brakes all around.  I can make out a "D76" and "256" on the cylinder.  The casting number "5452310 Y" is clearly stamped on the cylinder.  I'm not sure what the D76 and 256 signify although I believe they might be the foundry pattern number and Julian date code.  I also think the correct application code should be "BS" for a 1968 drum brake master cylinder, but I can't make-out the stamp on the cylinder.  Perhaps 50 years has done some damage to the location.  Any help in determining whether the mcb is actually correct for the car and decoding the numbers would be greatly appreciated.  Many thanks.  gwp4 

[stovebolt]

The codes you refer to make sense for your car. The D76 should be stamped on the front outlet boss and is the Julian assembly date of the M\C. BS is the correct application code for manual drum brakes all around. On the bottom of the M\C is a cast casting date which should precede the assembly date. The one pictured is from my 1968 04A coupe. The casting date is C8 8 or March 8, 1968. The assembly date is 78 8 or March 17 1968. I hope this helps you. Joe.

[gwp4]

Hi Joe -

I really appreciate your reply.  I'd like to get a little clarity on what you noted.  What is the date that the "D76" on the M/C indicates?  Also, what does the "236" or "238" on the M/C specify?  Also, I didn't find any cast casting date.  Did all of the M/C's have them?  I also haven't been able to determine if there is a "BS" application stamp on the M/C, but my car had manual drum brakes all around.  I've attached a few photos for your reference.  My car was assembled on May 14, 1968.  Many thanks.  gwp4

[z28z11]

Read the section in "Master Cylinders" concerning the appearance of a "CT" coded 310 cylinder - it could be a "CT" stamped there instead of a "_Y".

http://www.camaros.org/suspen.shtml#Brakecomp

Regards,
Steve

[stovebolt]

Based on the photo of your M/C I think your assessment was correct: D76 is the foundry pattern code and 238 must be the Julian casting date: 23rd day of 1968. The assembly date should be stamped on the forward fluid outlet boss. The foundry pattern code on my M/C is T37 which probably explains the differences in the locations of codes and the different casting date format. I apologize if my first comment misled you.

[ZLP955]

Julian date would be the 238th day of the calendar year

[gwp4]

Hi First Gen Camaro Experts:

I'm sorry I haven't posted a response for quite some time.  I'm still trying to figure out what the numbers mean on my master brake cylinder.  I thought the cylinder was original to the car, which was assembled on May 14, 1968, but I wanted to make sure.  I've been able to make out the numbers 5452310 Y, D76 and 256 or 258 (see attached photos).  I believe the 5452310 is the casting number, and the D76 might be the foundry number, but I'm stumped on the 256 or 258 number.  It might be a Julian date code, but I'm not sure.  If it's a Julian date, then that would equate to sometime around September 13, which is past the actual assembly date.  I'd really appreciate someone who could solve this riddle.  Many thanks.  gwp4 

[KurtS]

D76 is the foundry pattern code and 238 must be the Julian casting date: 23rd day of 1968. The assembly date should be stamped on the forward fluid outlet boss.

Julian date would be the 238th day of the calendar year

Correct.
btw, I've never seen any stamped assembly dates on a MC.