Are brake master cylinders date coded?
 

My '66 appears to have the wrong brake master cylinder, as follows:

http://i54.tinypic.com/nyi542.jpg

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:

http://i55.tinypic.com/10clwgj.png

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

The lower photo shows the correct casting style for '65-'66 model year. The upper photo with the bails & one-piece cap is '67 & later style.

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?

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?

Hey gbvette62, thanks for that detailed response. Just the information that I was seeking. :thumbs: Didn't know about the repro on the horizon either. :thumbs:

they are out. :cheers:

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]http://i54.tinypic.com/2prw569.jpg[/IMG]

That's very interesting. Thanks. So what date would the unit above be?

Thanks :thumbs: Available from whom?

Caliper Date
 

April 8th 1966, or 65, depending on when your car was built.

bt

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:

http://i54.tinypic.com/6r4zsp.png

Lone Star Corvette

1965 http://www.lonestarcaliper.com/ps-77...-cylinder.aspx

1966 http://www.lonestarcaliper.com/ps-78...-cylinder.aspx

call for price :ack:

Thanks, but these don't appear to be repros (as in reproductions)?

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.

The ones listed on Lonestar's website are rebuilt originals, and require a rebuildable core, or an expensive core charge.

The ones Lonestar had that had GM/Delco markings and numbers, were rebuilt originals. The ones without any numbers, are an old replacement 65-66 power MC, that was made years ago by a company that is no longer in business. I think it was the same company that originally made the heavy-duty rear end covers. Gentilli maybe??????

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.:willy: I think these have the original GM numbers on them, but they may not have the Delco logo? :cheers:

Corvette Stainless Steel Brake Inc


http://www.cssbinc.com/c2mastercylinders.aspx

Good stuff gbvette62 and Donald:

Here's what appears on CSSB's website:

http://i52.tinypic.com/14y0p4g.png

The CSSB GM-licensed/correct '65-'66 power master cylinders are $849.99. :thumbs:

Thanks!