Rear caliper ID

[Ian S.]

Hello,

The rear brake calipers on my car have the following casting numbers

Left outer 5473807
Left inner 5452281
Right outer 5473807
right inner 5473806

According to the tech manual only the 5473807 is correct. But I have seen other posts saying that 5473807 is correct for both outers and 5473806 is correct for an inner. What casting numbers should I have? The car is a late '66.

Thanks,

Ian

[Howard]

Re: Rear caliper ID

The experts will tell you for sure but #547 castings are from 73-82 cars, #545 are for 67-72 and #546 are correct for 65-66 cars. ..HN

[Joe L.]

Re: Rear caliper ID

Ian-----

NONE of the caliper casting numbers which you've provided are correct for 1966 rear calipers. The correct rear caliper casting numbers are 5465902 and 5465905. These are difficult find.

[Joe L.]

Addendum

Also, finding these calipers in the ORIGINAL configuration with cast-in piston guides is even more difficult than finding these casting numbers. Most of these calipers have been "converted" to 2nd design by brake rebuilders and, in doing so, the piston guides are machined out. It can be seen externally, though.

[Joe L.]

Correction

The word "can" at the end of the third line should be "CAN'T"

[Eugene B.]

Re: Series 1 calipers

Joe,
From the casting numbers and the description, you are saying that a late '66 Corvette came equipped with DM, Series 1 calipers. Don't misunderstand me, I am not saying that you are wrong but I understood that Series 1 calipers were only used on '65's.

Please provide clarification so that I can increase my understanding.

Thanks,
Gene

[Joe L.]

Re: Series 1 calipers

Gene-----

The 1st design calipers which used guided pistons, integral piston guides, and 1/4" thick Pyroceram insulators on the face of the piston were used for both 1965 and 1966. They were also used for very early 1967, too.

[Eugene B.]

Re: Thanks, Joe - note to Ian

Joe,
Thank you for the clarification.

Ian,
Now that we know the correct calipers for your car, it is possible to give you information where they can be found if you're interested.

I'm sure that you can get the Series 1 calipers from Ken at Lonestar Caliper Co. I had Lonestar sleeve and refurbish my original '65 calipers a couple of months ago. There are other numbers on the calipers (maybe date codes) that might be a problem, but Ken will know.

Hope this info is helpful,
Gene

[Ian S.]

Re: Thanks, Joe - note to Ian

Thanks for the help everyone.

I'll give lonestar a call Gene, thank you.

Ian

[Frank H.]

insulated pistons?

vette brakes lists the 65-66 calipers on their website and catelog,they come with insulated and guided pistons which cost almost as much as the calipers purchaced alone.
Gene
Did the lonestar calipers come with insulated pistons?

[Eugene B.]

Re: insulated pistons?

Frank,
Thank you for your Email. I was unaware that Vette Brakes offered Series 1 calipers.

Regarding my calipers. I looked for long time to find someone who would rebuild and sleeve my original '65 calipers. Most rebuilders will not touch them, or they want to machine out the guide posts inside the cavity and use the later design pistons.

Lonestar was able to use all 16 of my original pistons. They only bored, sleeved, replaced seals, etc. I'll check the VB website, but if their pistons are that expensive I'd give Ken a call if I needed some.

Best regards,
Gene

[Joe L.]

Re: insulated pistons?

Gene----

I'm EXTREMELY surprised that your original pistons were re-usuable. I've never seen a Corvette brake caliper piston that came out of a caliper, first or second design, that was re-usable. In almost all cases, the sealing ridge immediately behind the seal is worn. This can be discerned by carefully inspecting this area on the piston. If the "gold" hard-anodize is worn through (as it almost always is), the piston is scrap. If there is ANY corrosion-induced damage in this area (as there often is), then the piston is scrap, too.

Basically, the pistons have to be PERFECT, especially in the area that I described, for continued use. The pressures which occur in a hydraulic brake system are not forgiving of anything less.

[Ian S.]

design 1 or 2

Why did GM change to the second design and is there any performance differance between the two series? If the numbers can not be judged is there any reason to go with one or the other except to keep the car as original as possible?

Thanks,

Ian

[Dan Pepper]

Re: insulated pistons?

Frank,

Vette brakes doesn't offer 1st design calipers as a stock item. I know this becuase I called VB to inquire about buying a set for my '66. They will rebuild you a set of 1st design calipers... if you send them in.

[Joe L.]

Re: design 1 or 2

Ian------

Supposedly, GM went to the "2nd design" since it performed better in normal street usage and is less susceptible to the "air pumping" problem. I don't buy it, though. I think that the main reason was COST. The "1st design" has to be a LOT more costly to manufacture than the "2nd design". In fairness, though, I think that what happened was that the "1st design" didn't deliver enough benefit and VALUE to most customers to justify its cost to install on the cars. And, that's why GM changed, and appropriately so. "Material cost allocation" is a fact of life with car manufacturers. When you're shooting for a certain "target cost" for the finished car, you have to make decisions about where to expend the bucks that it costs to build the car. In other words, could the extra bucks that the "1st design" calipers cost be better used elsewhere to provide more VALUE to the customer? I think that the answer was yes!