Master Cylinder Identification
Thread Starter
Instructor
Joined: Jun 2008
Posts: 180
Likes: 13
From: Boston Massachusetts
Master Cylinder Identification
I'm a rookie forum member looking for some help in identifying a master cylinder. The Part # appears to be 5460346 though I'm wondering what the sideways 'Y' and "dot" above the number signify. The Julian Date on the other side of the MC is 349, so it was manufactured late in a model year; the question is, how can I determine the year? Thanks for your assistance.
Team Owner
Joined: Sep 2006
Posts: 31,302
Likes: 4,391
From: Westminster Maryland
Hi Phil,
Look very closely for a separate 4th digit where the Julian date is stamped.
I believe it was typically first and a bit away from the 'day' stamp.
Could yours be the 49th day of 1973?
Regards,
Alan
Something like….. 0 336
336th day of 1970.
Look very closely for a separate 4th digit where the Julian date is stamped.
I believe it was typically first and a bit away from the 'day' stamp.
Could yours be the 49th day of 1973?
Regards,
Alan
Something like….. 0 336
336th day of 1970.
Last edited by Alan 71; Jul 7, 2016 at 03:05 PM.
Thread Starter
Instructor
Joined: Jun 2008
Posts: 180
Likes: 13
From: Boston Massachusetts
Alan:
Thank you for the prompt response. I realized after reading your post that this is an early-C3 master cylinder (has bleeders). I'm looking for one for my '79, which I believe is the same Part # without the bleeders. I'm not an expert, so I may be wrong about this. By way of explanation, the item in the photos is presently for sale on ebay. Anyway, thanks again.
Phil
Melting Slicks
Joined: Jul 2006
Posts: 3,103
Likes: 802
From: Massapequa Park NY
For some reason the eBay one does not have the bleeders.
Also, Alan is talking about STAMPED numbers in the machined area, the numbers you mention are the CAST dated numbers. Two different things. The machined stampings usually give the year date. He has them pictured badly in the auction and does not mention those numbers in the description but that will give you the year date.
Also, Alan is talking about STAMPED numbers in the machined area, the numbers you mention are the CAST dated numbers. Two different things. The machined stampings usually give the year date. He has them pictured badly in the auction and does not mention those numbers in the description but that will give you the year date.
Last edited by ed427vette; Jul 8, 2016 at 06:01 AM.
Race Director
Joined: Oct 2000
Posts: 12,687
Likes: 3,139
From: Shamong, NJ
The "346" casting master cylinder was used for 67-76 Corvettes with power brakes.
67-72's 346's can be identified by a half moon shaped machined surface on the top front of the master cylinder, with a "PG" stamped into the machined face. All 67-72's have two bleeders in the flat area above where the brake lines attach.
346's used in 73, and to some point in 74, still have the bleeders, but don't have the half moon shaped machined surface, or an identification code stamped into the master cylinder.
Late 74 through 76 346"s are basically the same as the 73-early 74 346, but there are no bleeders in them.
67-76 manual brake master cylinders were casting number "5480509". 67-76 509's look the same as 346's, except that 67-72 manual brake 509's are stamped "DC" on the machined half moon shaped front pad.
The 346 posted by the OP, does not have any bleeders in it, so I believe it is a late 74-76 power brake master cylinder.
I don't know of any significance to the sideways "Y", the dot, the X, the 95 or the 349 cast into the master cylinder, but are likely mold identifiers, or other foundry marks.
67-72's 346's can be identified by a half moon shaped machined surface on the top front of the master cylinder, with a "PG" stamped into the machined face. All 67-72's have two bleeders in the flat area above where the brake lines attach.
346's used in 73, and to some point in 74, still have the bleeders, but don't have the half moon shaped machined surface, or an identification code stamped into the master cylinder.
Late 74 through 76 346"s are basically the same as the 73-early 74 346, but there are no bleeders in them.
67-76 manual brake master cylinders were casting number "5480509". 67-76 509's look the same as 346's, except that 67-72 manual brake 509's are stamped "DC" on the machined half moon shaped front pad.
The 346 posted by the OP, does not have any bleeders in it, so I believe it is a late 74-76 power brake master cylinder.
I don't know of any significance to the sideways "Y", the dot, the X, the 95 or the 349 cast into the master cylinder, but are likely mold identifiers, or other foundry marks.
Thread Starter
Instructor
Joined: Jun 2008
Posts: 180
Likes: 13
From: Boston Massachusetts
The "346" casting master cylinder was used for 67-76 Corvettes with power brakes.
67-72's 346's can be identified by a half moon shaped machined surface on the top front of the master cylinder, with a "PG" stamped into the machined face. All 67-72's have two bleeders in the flat area above where the brake lines attach.
346's used in 73, and to some point in 74, still have the bleeders, but don't have the half moon shaped machined surface, or an identification code stamped into the master cylinder.
Late 74 through 76 346"s are basically the same as the 73-early 74 346, but there are no bleeders in them.
67-76 manual brake master cylinders were casting number "5480509". 67-76 509's look the same as 346's, except that 67-72 manual brake 509's are stamped "DC" on the machined half moon shaped front pad.
The 346 posted by the OP, does not have any bleeders in it, so I believe it is a late 74-76 power brake master cylinder.
I don't know of any significance to the sideways "Y", the dot, the X, the 95 or the 349 cast into the master cylinder, but are likely mold identifiers, or other foundry marks.
67-72's 346's can be identified by a half moon shaped machined surface on the top front of the master cylinder, with a "PG" stamped into the machined face. All 67-72's have two bleeders in the flat area above where the brake lines attach.
346's used in 73, and to some point in 74, still have the bleeders, but don't have the half moon shaped machined surface, or an identification code stamped into the master cylinder.
Late 74 through 76 346"s are basically the same as the 73-early 74 346, but there are no bleeders in them.
67-76 manual brake master cylinders were casting number "5480509". 67-76 509's look the same as 346's, except that 67-72 manual brake 509's are stamped "DC" on the machined half moon shaped front pad.
The 346 posted by the OP, does not have any bleeders in it, so I believe it is a late 74-76 power brake master cylinder.
I don't know of any significance to the sideways "Y", the dot, the X, the 95 or the 349 cast into the master cylinder, but are likely mold identifiers, or other foundry marks.
Thanks for the detailed information. I made the original post with the photos showing two sides of the master cylinder on ebay. To clarify, Alan responded to my post with a photo of a different master cylinder (not the one on ebay) to illustrate the location and nature of the date stamping. Thanks again for the helpful information.
