C2 Original Muffler hangers?

[Rick B.]

Hoping everyones having a good Sunday

Love to understand more about 64-67 Muffler hangers, and identifying Original hangers versus Repros. Details about the "PM" stamp? Material? finish? Production vs Service differences? hardware? etc.

Hoping to get Joe to way in here....AIM part number is 3849775-76

I am sure its pretty basic but an area i do not know much about.

any help much appreciated

[Joe L.]

Re: C2 Original Muffler hangers?

Hoping everyones having a good Sunday

Love to understand more about 64-67 Muffler hangers, and identifying Original hangers versus Repros. Details about the "PM" stamp? Material? finish? Production vs Service differences? hardware? etc.

Hoping to get Joe to way in here....AIM part number is 3849775-76

I am sure its pretty basic but an area i do not know much about.

any help much appreciated

Rick------

I don't think there was any difference between the PRODUCTION and SERVICE 64-67 muffler hangers, GM #3849775 and 3849776. However, in later SERVICE I think the manufacturer's ID was either eliminated or changed.

The hangers were natural mild steel and used what I would describe as thick, cord-reinforced rubber for the "elastic" component. Later SERVICE may have changed to some sort of "salvaged" rubber (e.g. old tires, scrap conveyer belting, etc.).

I do not know how the reproductions differ from the original GM pieces. However, I can tell you that the reproductions of the 68-72 hangers are near perfect reproductions of the originals. I would expect the same for the 64-67.

[Rick B.]

Re: C2 Original Muffler hangers?

Thanks Joe!

The manufacturers ID being the "PM"? And no Part Numbers were stamped on the service pieces?

[Joe L.]

Re: C2 Original Muffler hangers?

Thanks Joe!

The manufacturers ID being the "PM"? And no Part Numbers were stamped on the service pieces?

Rick-----


I don't recall seeing any stamped part numbers on the hangers. I'm not 100% sure, but I just don't recall any.

[Joseph M.]

Re: C2 Original Muffler hangers?

Does anyone know how Gardners' hangers compare to originals?

[Doug L.]

Re: C2 Original Muffler hangers?

I can't comment on reproduction hangars but here are 3 photos of the original hangars from my '64. The steel parts were sandblasted and I avoided hitting the corded rubber as much as possible. Steel was then treated with Prelube 6. Sorry about the quality of the photos. It's dark under there even with a flash.

I find no evidence of anything stamped on the hangars.

[Scott S.]

Re: C2 Original Muffler hangers?

I can't comment on reproduction hangars but here are 3 photos of the original hangars from my '64. The steel parts were sandblasted and I avoided hitting the corded rubber as much as possible. Steel was then treated with Prelube 6. Sorry about the quality of the photos. It's dark under there even with a flash.

I find no evidence of anything stamped on the hangars.

Doug,

The "PM" stamp on both of mine is on the back side of the smaller of the two metal sections (bottom section in all three of your photos), not visible when installed.

[Rick B.]

Re: C2 Original Muffler hangers?

Thanks guys, I have seen the "PM on both metal ends.

Scott what bolt headmarks are yours? I am aware of WB's for the lowers and have heard RSC's.

also have heard TR's at the upper attachment.

[Ronald L.]

Re: C2 Original Muffler hangers?

Rick,
I have pulled RSC's and WB 122007 bolts from original brackets, nice ones too! The 122007 was used several places on 66 67 cars. I'm thinking you'll find it was WB in the 63 - 65's.

[Scott S.]

Re: C2 Original Muffler hangers?

Thanks guys, I have seen the "PM on both metal ends.

Scott what bolt headmarks are yours? I am aware of WB's for the lowers and have heard RSC's.

also have heard TR's at the upper attachment.

Rick,

I had GM service exhaust hangers (GM 3849775 & GM 3849776) from 11-04-77 (purchase date on receipt), they still have the GM stickers on the rubber section. The metal was corroded, but I found the "PM" stamping on the back side of the small metal section on both after a trip to the bench grinder.

The correct bolts should be GM 122007 (UPC 8-A3, Item 23). Only two bolts survived disassembly, one from the smaller metal section of each hanger. They are too corroded to see anything on the top of the bolt head, but they are 1" long, which is 1/4" too long to have been originals.

I found a used set that were claimed to be "original" exhaust hangers from a western car, the "PM" stamp was in the same place as the 1977 GM service replacements.

[Doug L.]

Re: C2 Original Muffler hangers?

This morning I had to unfasten my left muffler from its hanger and pull the rear pipe loose from the front pipe to install a new speedometer cable. While the muffler was off I looked at the face of the lower metal part of the hanger, the surface that will be against the mounting bracket on the muffler, and the "PM" was there, upside down as installed.

[Ronald L.]

Re: C2 Original Muffler hangers?

On this topic of the fasteners for this hanger, does anyone know what the ID/OD of the p. washer 9419275 was?

This RSC 122007 bolt, nut, l. washer, P. washer is off a 66, the p. washer looks original like the rest, but small.

Comments/ data on the p washer size?

[Scott S.]

Re: C2 Original Muffler hangers?

On this topic of the fasteners for this hanger, does anyone know what the ID/OD of the p. washer 9419275 was?

This RSC 122007 bolt, nut, l. washer, P. washer is off a 66, the p. washer looks original like the rest, but small.

Comments/ data on the p washer size?

Ron,

The only example I have that I'm fairly sure is original is on the engine bay side of the steering column ('67 only), specifically the clamp at the firewall (1967 AIM, UPC 9-A4, Item 8, GM 9419275 Washer).

It is slightly bent and gouged from the bolt head just like your examples, with an ID of 11/32" and an OD of 5/8", just slightly larger than the 1/2" ATF measurement of the 122007 bolt head. Seems like a match to the ones in your photos. Just one data point though, more examples would help

GM 9419275 was used in the following applications (could be more than just these):

Exhaust hangers: 1964-1967
Headlamp Opening Brace Rod (upper, LH & RH): 1964-1967 (UPC 12-A4 in '66 AIM)
Headlamp section, Nose header bar: 1966-1967 (UPC 12-A2, item 25 in '66 AIM)

[Ronald L.]

Re: C2 Original Muffler hangers?

Now for the six million dollar question on these hangers...

Which way is the rivet head, hollow peen over - or - the flat head on the outside of the loop?

[Scott S.]

Re: C2 Original Muffler hangers?

Now for the six million dollar question on these hangers...

Which way is the rivet head, hollow peen over - or - the flat head on the outside of the loop?

For six million dollars, I could find the correct answer to that question.