Ceremetalix Shoes and Other RPO 684 - 687 Parts

[Russ U.]

A few months ago, a nice Big Brake setup sold on ebay for a fairly meaningful sum. Ebay Big Brake Setup. A guy in the SF Bay Area saw the ebay deal, and realized that he had basically had the same setup sitting in his garage - he didn't realize the parts were valuable. So he put his setup on ebay as well, but his ebay description stated that the parts were for sale locally. Right after the ebay listing went up, I contacted seller #2 to ask a question about his setup. Ebay then yanked the listing because the seller stated the setup was for sale locally. As luck would have it, the big brake setup was only 40 miles from my house, and I was able to inspect and buy the setup in a private transaction.

Before inspecting the big brake setup, I tried to research what parts came with a big brake setup. My main interest was the drums - I need fresh drums for my 57 vintage race car. The drums in the setup I purchased are nearly new, with an inside diameter of 10.995 to 11 inches. But I had a hard time educating myself about what to look for in a big brake setup. Fortunately, a few of the more seasoned members in the hobby reasoned very quickly to my pleas for help, and I muddled my way thru.

The best article dealing with Big Brakes that I found on the internet was authored by Jerry Wagner - Solid Axle RPO Cars. I also found several Restorer Articles, and an article by Wilson Swilley in the Northern California NCRS Chapter written 20 years ago or so. But none of the articles combine both great text with plenty of high quality pictures. Which is the reason for this post.

One of the key items in a big brake setup is an elliptical anchor bolt. I could not find a picture of this anywhere on the internet or in Restorer magazines. Thus, I didn't know what to look for when I checked out my big brake setup. Too bad. My setup lacked the elliptical bolts. And I still don't know what they look like. So if anybody could post a picture, that would be great.

My setup did come some good stuff other than fresh drums - very fresh Ceremalix shoes made by Bendix (first design), vented backing plates (second design), air scoops for the rears (second design), and 649 cylinders for the front and 400 cylinders for the back. Photos of these are attached below (for the rear only), and please comment about anything you see. (I will probably trade some of these parts later on, and I would appreciate hearing any comments that would allow me to accurately describe this stuff.)

From what I can tell, the setup is a mixed lot of some neat parts. Probably purchased over the counter. And then the car was apparently wrecked right after the fresh drums were put on.

Russ

[Mike E.]

Re: Ceremetalix Shoes and Other RPO 684 - 687 Parts

A few months ago, a nice Big Brake setup sold on ebay for a fairly meaningful sum. Ebay Big Brake Setup. A guy in the SF Bay Area saw the ebay deal, and realized that he had basically had the same setup sitting in his garage - he didn't realize the parts were valuable. So he put his setup on ebay as well, but his ebay description stated that the parts were for sale locally. Right after the ebay listing went up, I contacted seller #2 to ask a question about his setup. Ebay then yanked the listing because the seller stated the setup was for sale locally. As luck would have it, the big brake setup was only 40 miles from my house, and I was able to inspect and buy the setup in a private transaction.

Before inspecting the big brake setup, I tried to research what parts came with a big brake setup. My main interest was the drums - I need fresh drums for my 57 vintage race car. The drums in the setup I purchased are nearly new, with an inside diameter of 10.995 to 11 inches. But I had a hard time educating myself about what to look for in a big brake setup. fortunately, a few of the more seasoned members in the hobby reasoned very quickly to my pleas for help, and I muddled my way thru.

The best article dealing with Big Brakes that I found on the internet was authored by Jerry Wagner - Solid Axle RPO Cars. I also found several Restorer Articles, and an article by Wilson Swilley in the Northern California NCRS Chapter written 20 years ago or so. But none of the articles combine both great text with plenty of high quality pictures. Which is the reason for this post.

One of the key items in a big brake setup is an elliptical anchor bolt. I could not find a picture of this anywhere on the internet or in Restorer magazines. Thus, I didn't know what to look for when I checked out my big brake setup. Too bad. My setup lacked the elliptical bolts. And I still don't know what they look like. So if anybody could post a picture, that would be great.

My setup did come some good stuff other than fresh drums - very fresh Ceremalix shoes made by Bendix (first design), vented backing plates (second design), air scoops for the rears (second design), and 649 cylinders for the front and 400 cylinders for the back. Photos of these are attached below (for the rear only), and please comment about anything you see. (I will probably trade some of these parts later on, and I would appreciate hearing any comments that would allow me to accurately describe this stuff.)

From what I can tell, the setup is a mixed lot of some neat parts. Probably purchased over the counter. And then the car was apparently wrecked right after the fresh drums were put on.

Russ

Russ--
Several comments--649 wheel cylinders are also rears, and are unbelievably common because they were used on many GM products of the time in addition to the Corvette. 627/628 and 821/822 are the correct fronts for that time period for the RPO 684/687 cars.
The shoes that you picture separately appear to me to not be correct as they should be segmented (a line down the middle of each pad because they were two pads side by side rather than a single pad.)
The elliptical pin looks almost identical to the regular pin--it's just that the round surface against which the top of each shoe butts up is off-center rather than centered. You really have to look twice in order to see that it's not a regular pin.
Looks like a pretty good pickup!
I have two pretty much complete sets of RPO 687 stuff, including backing plate covers, but don't want to part that stuff out and break up a set.

[Russ U.]

Re: Ceremetalix Shoes and Other RPO 684 - 687 Parts

Russ--

The shoes that you picture separately appear to me to not be correct as they should be segmented (a line down the middle of each pad because they were two pads side by side rather than a single pad.)

Thanks for the info Mike. I am a bit baffled by the shoes. Jerry Wagner's web info says that the early Ceremalix shoes came with two pads on the primary and 4 pads on the secondary, like the shoes on my setup. My shoes are also stamped with Bendix on the inside of the shoes, and the pads are copper in color. I thought Bendix made the original Ceremalix shoes, and that the pad count was correct for a Bendix Ceremalix shoe.

I am looking at a Spring 1993 Restorer article as well (by Masciarella and Bartush). They describe the 57 to early 59 Ceremetalix shoes as having 2 pads on the primary and 4 on the secondary. They include a pic of the shoe as well - the pic shows large pads like the ones I have (the pic is small and dark, however, so could be open to interpretation). The pads don't look segmented.

I thought segmented pads popped up with the sintered metallic shoes.

I appreciate your insights Mike.

Russ

[Lou C.]

Re: Ceremetalix Shoes and Other RPO 684 - 687 Parts

Russ, Photos of a 61 RPO 687 car.

[Bob J.]

Re: Ceremetalix Shoes and Other RPO 684 - 687 Parts

Russ, were the elliptical bolts just used in the front?
Were all 57-62 elliptical bolts the same? Bob

[Russ U.]

Re: Ceremetalix Shoes and Other RPO 684 - 687 Parts

Russ, were the elliptical bolts just used in the front?
Were all 57-62 elliptical bolts the same? Bob

I have no idea. The literature I have suggests not limit the elliptical or eccentric pin to just the front. But I have never seen one, so I don't know. The pins on my rears are in the center, so I think they are standard issue. My front hubs are 150 miles away, so I cannot check them again for a few weeks.

I sure would like to see a standard bolt and an eccentric bolt side by side.

Russ

[Lou C.]

Re: Ceremetalix Shoes and Other RPO 684 - 687 Parts

Front and rear. These photos are of the back of the elliptical pins.

[Russ U.]

Re: Ceremetalix Shoes and Other RPO 684 - 687 Parts

GREAT PICS!!!!! Thanks Lou.

After scouring the internet and Restorer magazines, this is the first pic of the eccentric pin I have seen.

This unfortunately confirms that my setup lacks the eccentric pins. What the heck. At least I know what to look for next time.

Russ

[Justin B.]

Re: Ceremetalix Shoes and Other RPO 684 - 687 Parts

Russ,
I feel very confident that your brake shoes are the right ones for your car. They were built by Bendix and should say Bendix on them and have that copper colored material. They are extremely valuable so hold on to them!! The segmented, gray in color pads are for the later RPO 687 cars. This is also mentioned in the Spring, 1993 edition of the NCRS Restore magazine which covers many of the special details of the RPO 684 system and also provides pictures.
I have a very original 58' RPO 684 car and even though it was not missing many of the big brake goodies...I have learned that opinions vary with what cars have what parts and I guess its because there is so little documentation out there. JB

[Jim L.]

Re: Ceremetalix Shoes and Other RPO 684 - 687 Parts

The literature I have suggests not limit the elliptical or eccentric pin to just the front.

The old Floyd Clymer Corvette Owner's Handbook says the elliptical anchor pin was used only on the front and a standard pin with only vertical travel was used on the rear.

This same book also has a black and white photo of the Ceremetallix shoes, the appearance of which matches the shoes you bought. Each pad is one monolithic segment, not a pair of segments as found on the later, sintered metallic shoes.

Jim

[Bill M.]

Re: Ceremetalix Shoes and Other RPO 684 - 687 Parts

The old Floyd Clymer Corvette Owner's Handbook says the elliptical anchor pin was used only on the front and a standard pin with only vertical travel was used on the rear.

Jim

I'll bet that was some sort of a mis-print because if memory serves that describes the difference between vented and standard FRONT backing plates (it's too cold in the garage to confirm!)

My fine-mesh (early) rear backing plates have eccentric pins and don't have the slot that would provide only vertical travel.

[Jim L.]

Re: Ceremetalix Shoes and Other RPO 684 - 687 Parts

I'll bet that was some sort of a mis-print because if memory serves that describes the difference between vented and standard FRONT backing plates (it's too cold in the garage to confirm!)

It very well could be a misprint but if it is, the fault probably lies back at Helm Inc. The Clymer book borrows heavily from GM-published manuals and literature. I don't think there is an original sentence in the whole book.

That said, yes, one of many differences between the RPO backing plates and the standard backing plates is how the anchor pin can move to properly locate the shoes. Standard front plates use an anchor pin that can move up and down only.

My fine-mesh (early) rear backing plates have eccentric pins and don't have the slot that would provide only vertical travel.

Do we know for sure the rear backing plates didn't undergo a design revision during the life of the RPO 684/687 brakes? Since the rears are significantly less important (no, not unimportant!) than the fronts, it seems plausible that, in light of this, a change to the less expensive, standard type of anchor pin might have been made somewhere along the way.

I have no idea one way or another.... just thinking out loud, so to speak.

Jim

[Bill M.]

Re: Ceremetalix Shoes and Other RPO 684 - 687 Parts

Do we know for sure the rear backing plates didn't undergo a design revision during the life of the RPO 684/687 brakes? Since the rears are significantly less important (no, not unimportant!) than the fronts, it seems plausible that, in light of this, a change to the less expensive, standard type of anchor pin might have been made somewhere along the way.

I have no idea one way or another.... just thinking out loud, so to speak.

Jim

I know that the mesh went from fine to coarse at some point and that the washer at the anchor pin on the 684 plates was deleted when the shoe width changed for the 687 package. I've never seen any info on the anchor pin changing...

[David D.]

Re: Ceremetalix Shoes and Other RPO 684 - 687 Parts

Wow, great stuff! My garage is heated so I'm headed under the car! Don't you think that this stuff varied quite a lot perhaps even month to month. I could feel comfortable that if as a 22 year old kid working an assembly line some where, I just used what was in the box and if the box was empty I simply grabbed something else.

[Bill M.]

Re: Ceremetalix Shoes and Other RPO 684 - 687 Parts

It very well could be a misprint but if it is, the fault probably lies back at Helm Inc. The Clymer book borrows heavily from GM-published manuals and literature. I don't think there is an original sentence in the whole book.

Jim

You got that right. The same description is in the Corvette Chassis Service Operations book from Chevy, page 31. The book covers through 1960.

I remember being disappointed that too much of Clymer's book was a reprint of my '59 owner's manual. (I probably bought Clymer's book in about 1963.)