Are brake master cylinders date coded?
Thread Starter
Burning Brakes
Joined: Jan 2011
Posts: 755
Likes: 4
From: Toronto Ontario
Are brake master cylinders date coded?
My '66 appears to have the wrong brake master cylinder, as follows:
I understand that the '66 had a master cylinder that was unique to two years of production, I believe '65 and '66. Is this correct?
The correct part looks like this:
I am in no particular hurry to return this part to original but intend to be on the look out for the correct part. In doing so, I need to know whether the brake master cylinder for a '66 is date coded.
BTW. My car's build date is October 8, 1965
I understand that the '66 had a master cylinder that was unique to two years of production, I believe '65 and '66. Is this correct?
The correct part looks like this:
I am in no particular hurry to return this part to original but intend to be on the look out for the correct part. In doing so, I need to know whether the brake master cylinder for a '66 is date coded.
BTW. My car's build date is October 8, 1965
Thread Starter
Burning Brakes
Joined: Jan 2011
Posts: 755
Likes: 4
From: Toronto Ontario
Thanks for confirming that. Are the castings for the '65-'66 model year dated? I don't want to go to the great expense of getting the proper part ($800 - $1,000) and not have the proper date. Are these castings dated?
Race Director
Joined: Oct 2000
Posts: 12,684
Likes: 3,137
From: Shamong, NJ
The original casting number of the 65-66 power MCs is 5467084, and is found cast into the side of the MC. More important than the date on these MCs, is the brake line diameter. These master cylinders came in two versions. The first design one was used for part of 65, and used a 3/16" line. The second design MC, was used for the later part of 65, and all of 66. The later one uses 1/4" lines. There are no markings on the MCs to differentiate which line size the master cylinder is, so you have to be careful to make sure you get the 1/4" line one.
If you can find a good useable 65-66 power MC for $800-$1,000, grab it. The re-builders pay $1,000 for cores. The 65-66 PB MC's always need to be sleeved. A stainless steel sleeved rebuilt, without a core, will set you back about $1,500.
There is a repro coming, but I'm not sure if it's available yet. I think the price is supposed to be around $350?
Thread Starter
Burning Brakes
Joined: Jan 2011
Posts: 755
Likes: 4
From: Toronto Ontario
Some MCs do have a date stamped on the flange, were they bolt to the booster. I don't recall if the 65-66 power MCs are dated though.
The original casting number of the 65-66 power MCs is 5467084, and is found cast into the side of the MC. More important than the date on these MCs, is the brake line diameter. These master cylinders came in two versions. The first design one was used for part of 65, and used a 3/16" line. The second design MC, was used for the later part of 65, and all of 66. The later one uses 1/4" lines. There are no markings on the MCs to differentiate which line size the master cylinder is, so you have to be careful to make sure you get the 1/4" line one.
If you can find a good useable 65-66 power MC for $800-$1,000, grab it. The re-builders pay $1,000 for cores. The 65-66 PB MC's always need to be sleeved. A stainless steel sleeved rebuilt, without a core, will set you back about $1,500.
There is a repro coming, but I'm not sure if it's available yet. I think the price is supposed to be around $350?
The original casting number of the 65-66 power MCs is 5467084, and is found cast into the side of the MC. More important than the date on these MCs, is the brake line diameter. These master cylinders came in two versions. The first design one was used for part of 65, and used a 3/16" line. The second design MC, was used for the later part of 65, and all of 66. The later one uses 1/4" lines. There are no markings on the MCs to differentiate which line size the master cylinder is, so you have to be careful to make sure you get the 1/4" line one.
If you can find a good useable 65-66 power MC for $800-$1,000, grab it. The re-builders pay $1,000 for cores. The 65-66 PB MC's always need to be sleeved. A stainless steel sleeved rebuilt, without a core, will set you back about $1,500.
There is a repro coming, but I'm not sure if it's available yet. I think the price is supposed to be around $350?
Didn't know about the repro on the horizon either.
Team Owner
Joined: Feb 2003
Posts: 54,124
Likes: 9,438
From: Sitting in his Nowhere land Hanover Pa
2024 C2 of the Year Finalist - Unmodified
2015 C2 of Year Finalist
Advanced
Joined: Dec 2004
Posts: 57
Likes: 1
From: Glendale Arizona
Master cylinder dates
The castings are Julian dated. The "date" is visable from the output line side of the housing. The attached show a "98" for example. The year is dictated by the size of the line.
[IMG]
[/IMG]
[IMG]
[/IMG]
Thread Starter
Burning Brakes
Joined: Jan 2011
Posts: 755
Likes: 4
From: Toronto Ontario
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Thread Starter
Burning Brakes
Joined: Jan 2011
Posts: 755
Likes: 4
From: Toronto Ontario
Thanks bt. You learn something new every day. Here is the Julian Day calendar (for a non leap year), at least the part that would fit into my screen shot. From this you can see how 98 translates into April 8th:
Team Owner
Joined: Feb 2003
Posts: 54,124
Likes: 9,438
From: Sitting in his Nowhere land Hanover Pa
2024 C2 of the Year Finalist - Unmodified
2015 C2 of Year Finalist
Lone Star Corvette
1965 http://www.lonestarcaliper.com/ps-77...-cylinder.aspx
1966 http://www.lonestarcaliper.com/ps-78...-cylinder.aspx
call for price
1965 http://www.lonestarcaliper.com/ps-77...-cylinder.aspx
1966 http://www.lonestarcaliper.com/ps-78...-cylinder.aspx
call for price
Thread Starter
Burning Brakes
Joined: Jan 2011
Posts: 755
Likes: 4
From: Toronto Ontario
Lone Star Corvette
1965 http://www.lonestarcaliper.com/ps-77...-cylinder.aspx
1966 http://www.lonestarcaliper.com/ps-78...-cylinder.aspx
call for price
1965 http://www.lonestarcaliper.com/ps-77...-cylinder.aspx
1966 http://www.lonestarcaliper.com/ps-78...-cylinder.aspx
call for price
Team Owner
Joined: Feb 2003
Posts: 54,124
Likes: 9,438
From: Sitting in his Nowhere land Hanover Pa
2024 C2 of the Year Finalist - Unmodified
2015 C2 of Year Finalist
I believe they are. when I looked at them At Corvettes At Carlisle you could get them without numbers or with. call and find out.
Race Director
Joined: Oct 2000
Posts: 12,684
Likes: 3,137
From: Shamong, NJ
Lone Star Corvette
1965 http://www.lonestarcaliper.com/ps-77...-cylinder.aspx
1966 http://www.lonestarcaliper.com/ps-78...-cylinder.aspx
call for price
1965 http://www.lonestarcaliper.com/ps-77...-cylinder.aspx
1966 http://www.lonestarcaliper.com/ps-78...-cylinder.aspx
call for price
They're coming from Corvette Stainless Steel Brakes (CSSB) of Miami, FL. Their website says "Coming Soon". I thought that I got a flier or new wholesale catalog from them recently, with the price and availability, but I can't find it at the moment.
I think these have the original GM numbers on them, but they may not have the Delco logo? 
Melting Slicks
Joined: Jul 2004
Posts: 2,867
Likes: 195
From: Maryland
