C1 62 brake drum part number?

[Duke W.]

Re: C1 62 brake drum part number?

The drawing number for the casting should be the casting number-3828686 Drawing number 3828686 would probably be a finished drum drawing number, and there would be at least two - one for base brakes and one for metallic brakes since the drums for both brake systems were machined from the same drum castings. The difference was just the finish of the friction surface.

Duke

[Duke W.]

Re: Sort This Out, Step One.....

"The 59-62 drum, part number 3752622, was still listed in the 1963 printing of the parts book and continued to be available until Nov of 1963..."

There should be two part numbers listed for 59-62 one for base brakes and one for RPO 686 Metallic Brakes. Which one is 3752622 and what is the other part number and application?

Duke

[Michael H.]

Re: Sort This Out, Step One.....

The 3752622 is the F&R drum part number listed for 59-62 Corvette WITHOUT metalic lining. It was replaced by 3828686, the previously unique to 63 part number, on 10-63.

The 3755504 is the F&R drum part number listed for 59-62 Corvette WITH metallic lining. It was replaced by 3828687, the previously unique to 63 part number, on 3-65.

Info is for std. and metallic lining only. The HD brake/susp package is another story completely. Numbers are from a March printing of the 1963 parts book. Hope this helps.

Michael

[Duke W.]

Re: Sort This Out, Step One.....

What were the original service numbers for the '63 front drums, base and metallic (J-65)?

Duke

[Chris H.]

Re: Sort This Out, Step One.....

So, back to what I was after in the first place at the start of this thread. 3752622 is the only production drum for the '62? I think you two have basically stated this and my rotor 3828688 needs to be replaced. Question is was 3752622 ever used in production on the '63?

Duke, you want to trade drums?

Chris

[Michael H.]

Re: Sort This Out, Step One.....

Chris,

I suppose it it possible that a few of the last 62's that rolled off the line COULD have had the new 63 style drums with the knockout for the adjuster, but I would guess that it probably didn't happen.

As far as the old style 59-62 drum on an early 63, it's not at all likely as there would be no way to adjust the brakes. The 63 backing plate has no adjuster slot and the 62 drum has no adjuster slot. Engineering would not have let anything like that out on the street. My guess is, your 3828688 was a service replacement some time between 1963 and 1965.

You and the Duke should write an article on all of this. I'll try to get casting numbers for you this weekend.

[Michael H.]

Duke, You Have Mail..... *NM*

[Duke W.]

Re: Sort This Out, Step One.....

Well it's quite interesting that one of the "original drums" on my SWC is casting number 3752627.

In 1968 when I was at Pontiac I had the rear metallic shoes replaced. I had a sticky parking brake cable, right side at I recall, and I had the local dealer free replace the cable and replace both side rear shoes. I've looked at the RO in the last couple of years and a drum was not replaced. When I completely overhauled the brakes in the mid to late seventies, I found three drums worn .060" and one worn .080", which jibes with the sticky parking brake cable issue, and I ordered new J-65 drums, which were still available from service parts.

Did the Pontiac, MI Chevrolet dealer somehow install the wrong drum on my car? Doesn't seem likely.

Regarding adjustment, the '63 brakes were self-adjusting, and I assume they were adjusted when the front knuckle and rear trailing arm assemblies were assembled. The only reason one would have to punch out the "knockout" on the outside face of the drum would be to back off the star wheel if the drum wouldn't slip over the shoes. Even with the wear on my drums, I never had to back off the adjustement to slip the drums off over the shoes, so the knockouts on the three drums are intact, and, of course, the 627 casting doesn't have a knockout.

All of this is of purely academic interest since drum casting numbers and the knockout is not visible during judging, so it's not a points deduction issue, but I think many with drum brakes would find a Corvette Restorer article interesting as it would enable them to ascertain whether installed drums are possibly original or likely service replacements.

I think that all three of us should share co-authorship. I currently have a paper and pencil chart with drum utilization, and as soon as I can get a copy of Chris' 801 drawing and whatever information Michael can dig up I might be able to nearly complete it. I'm also going to make queries on the availability of any drawings. I'm not holding my breathe than any might still be in the GM system, but it's worth a shot.

Once we've mined as much information as we think is available I will write up a draft and send it to both of you for review. Most of the work is going to be the research. Writing it up with a final chart summarizing the data will be almost trivial.

As far as swapping drums, Chris, that's an interesting proposal. The trouble is that my one 627 drum is worn, and I'm going to have to dig up a drum caliper to see if it is one of the three with .060" wear or the one with .080" wear. In any case, it is probably still useable. Since I've already replaced virtually everything on my J-65 system with Chevrolet service parts and none of the service drums have original factory installed casting numbers, I'm not too concerned about the numbers, especially since they aren't judged, but I never had any intention of disposing of the original drums. I just can't throw stuff out unless it's absolutely beyond service.

If we do swap, Chris, we may both have some 'splainin' to do when we eventually arrive at the pearly gates and St. Peter asks us if we really have original drums - either on the car or in a box.

Duke

[Chris H.]

Re: Sort This Out, Step One.....

Uh, if he ask me if I have all the parts the car came with I am gong the wrong way. My car got mixed up with a '63 and a '64 and a bunch of others somewhere in its life. I am just trying to get it back to being a twin of how it was born.

[Chris H.]

62 drums on 63

I just bought two '62 drums that were on somebodies '63 off ebay. Not saying they came with it but just another example.

Chris

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=4543011595