65/66 Master Cylinder Question

[David S.]

Hi all,

Suppose you have an original 65/66 master cylinder (non power brakes) with a julian date of 260 (Sept 17). How would you know if the year was 65 or 66?

Thanks,
Dave

[David L.]

Re: 65/66 Master Cylinder Question

Hi all,

Suppose you have an original 65/66 master cylinder (non power brakes) with a julian date of 260 (Sept 17). How would you know if the year was 65 or 66?

Thanks,
Dave

Assuming it was a factory installed master cylinder it would be Sept. 17, 1964, or Sept. 17, 1965. The only way it could be Sept. 17, 1966, is if it was sold over the counter since the 1967 Corvette w/VIN 194677S100007 has an engine assembled on August 18, 1966 ("V0818HE") as per Noland Adam's 63-67 restoration book. I assume that the body build date was in August 1966 as well. I believe that the last 1966 Corvette made was in July 1966.

My original 1966 (Feb. 1966 build) "2225032 R2" master cylinder is dated "325" or 325th day of 1965 (Nov. 21, 1965). Photos are in link below.

Dave

https://www.forums.ncrs.org/showthre...aster+cylinder

[Joe L.]

Re: 65/66 Master Cylinder Question

Assuming it was a factory installed master cylinder it would be Sept. 17, 1964, or Sept. 17, 1965. The only way it could be Sept. 17, 1966, is if it was sold over the counter since the 1967 Corvette w/VIN 194677S100007 has an engine assembled on August 18, 1966 ("V0818HE") as per Noland Adam's 63-67 restoration book. I assume that the body build date was in August 1966 as well. I believe that the last 1966 Corvette made was in July 1966.

My original 1966 (Feb. 1966 build) "2225032 R2" master cylinder is dated "325" or 325th day of 1965 (Nov. 21, 1965). Photos are in link below.

Dave

https://www.forums.ncrs.org/showthre...aster+cylinder

Dave------


Yes, assuming that the master cylinder was originally installed on a Corvette, the date would be either 1964 or 1965. The 1965 model year used a smaller brake line tubing nut that 1966 model year, so if it has the smaller size, then the date would be 1964. However, if it's the larger size (which replaced the smaller size for SERVICE with the use of adapters), it could be any year up until the time the master cylinder was discontinued. As I've stated before, without a year in the code, half of the master cylinders ever manufactured would be "correct".

[Ronald L.]

Re: 65/66 Master Cylinder Question

...unless you found some other subtle indicator on the castings

[Michael H.]

Re: 65/66 Master Cylinder Question

Dave------


Yes, assuming that the master cylinder was originally installed on a Corvette, the date would be either 1964 or 1965. The 1965 model year used a smaller brake line tubing nut that 1966 model year, so if it has the smaller size, then the date would be 1964. However, if it's the larger size (which replaced the smaller size for SERVICE with the use of adapters), it could be any year up until the time the master cylinder was discontinued. As I've stated before, without a year in the code, half of the master cylinders ever manufactured would be "correct".

Joe,

I think the brake line outlet fitting size would be the same for both 65 and 66 without power brakes.

[Joe L.]

Re: 65/66 Master Cylinder Question

Joe,

I think the brake line outlet fitting size would be the same for both 65 and 66 without power brakes.

Michael---

Oops, somehow I thought we were talking about a power brake car but looking back at the original post i don't see what gave me that idea.

[Michael H.]

Re: 65/66 Master Cylinder Question

Michael---

Oops, somehow I thought we were talking about a power brake car but looking back at the original post i don't see what gave me that idea.

Joe,

I thought, or assumed the same thing the first time I read David's post. I had to go back and read it again. I suppose that's because there has, and still is so much confusion about 65 and 66 power brake master cyl's and the 1st/2nd design for 65.

[David L.]

Re: 65/66 Master Cylinder Question

Pictured below is a 65-66 master cylinder that I bought at the Corvette Carlisle swap meet back in the 1980's or 1990's.
The casting # is "2225032", a special "B" logo (for Bendix, I assume), and the number "3".
The date code is "29-". Is this the 29th or 290th day of the year???

Dave

[Joe L.]

Re: 65/66 Master Cylinder Question

Pictured below is a 65-66 master cylinder that I bought at the Corvette Carlisle swap meet back in the 1980's or 1990's.
The casting # is "2225032", a special "B" logo (for Bendix, I assume), and the number "3".
The date code is "29-". Is this the 29th or 290th day of the year???

Dave

Dave------


I've always felt that the casting number on these master cylinders is a Bendix number, not a GM number. If it's a GM number it's from a series that I've never seen before.

[David L.]

Re: 65/66 Master Cylinder Question

Dave------


I've always felt that the casting number on these master cylinders is a Bendix number, not a GM number. If it's a GM number it's from a series that I've never seen before.

Joe,

I agree with you about the casting number being a Bendix number. I believe that the 1965-1966 Ford Thunderbirds used a very similar master cylinder.

Dave