Author Topic: 1956 Generator bracket mystery  (Read 61 times)

Offline Lexi

1956 Generator bracket mystery
« on: May 10, 2019, 07:06:15 PM »
My engine job assembly is progressing but I ran into a weird issue. After installing the generator it was then found to be "too far back", so the 2 belts (car has AC), were not lining up at 180 degrees. Generator has to come forward about 1/2 of an inch so the belts will be straight, (and thus wear evenly). Same generator & pulley used. I did, however, install a freshly painted 1956 Caddy generator mounting bracket to a pair of new studs I fitted into the exhaust manifold. This is where it gets weird.

When I compared the freshly painted mount to the one removed, I found that they were different. The one removed from the car was made of steel, while the others that I have here in parts are all cast iron. These cast iron units all came from 1955 and 1956 Caddies. They appear nearly identical to the steel one however, the cast iron units all have a gusset cast into the middle of them for added strength, (see pic with red arrow pointing to gusset). A superficial look would have one believe they were all Cadillac and factory made, same angles, etc. The steel one however, is thinner and has no gusset. I don't recall seeing any numbers stamped into the steel one and I have every reason to believe that it was factory made. Just not sure if Cadillac or a knock off done by another manufacturer.

Anyhow, as everything is stock this generator mounting problem surprised me. When the odd-ball steel mount was re-used, and admittedly the AC compressor was moved ever so-slightly, most of the 1/2 " or so of play was gone. A chunk of the correction seemed to come from the steel mount being re-used. Two mechanics looked at it and were mystified as mounting holes, etc all lined up in both, but the steel one fit so much better. We decided not to question our results and leave it. Sadly, I did not have an opportunity to photograph the odd-ball steel mount, but later I did photograph the regular cast iron unit that should have worked at least as well as the steel one, (but did not).

The Master Parts List notes that 1954, 1955 & 1956 mounts are identical. Also, if I read it correctly, no difference was stated if car equipped with AC or not, so it does not look like there were different mounting brackets offered. Has anyone ever encountered one of these steel generator mounting brackets before, as well as this fitment problem? I have also noticed another oddity that I will probably write up later. One Ripley's Believe it or Not for one day is enough.


P.S. These factory cast iron mounting brackets are probably under engineered and prone to breaking should certain conditions arise. Treat yours like gold, do not over torque or drop them.
« Last Edit: May 10, 2019, 07:19:56 PM by Lexi »

Offline South_paw

Re: 1956 Generator bracket mystery
« Reply #1 on: May 11, 2019, 06:30:09 AM »

I wonder if that steel bracket came from one of the many applications this generator was used for back then. Other makes, tractors, boats, etc.
1956 Eldorado Biarritz
CLC Member since 2001 (Unlisted in Directory)

*** Check out the 1956 Eldorado Biarritz Survivor Roster. Click here ***

Offline JAG56Cad

Re: 1956 Generator bracket mystery
« Reply #2 on: May 11, 2019, 06:43:04 AM »

Hmm very strange..!  :o

I have the one on your picture and have had no issues with lining up the gen and/or the A/C compressor with the belts.

I took a snap shoot of my scan page from the Service Manual (yes I can zoom the pages to 100% with no lost of resolution  ;)) and it shows a similar one you place in yours steel maybe, so ???

Not sure what would be the differences in dimension between the cast and the steel one since they both would mount and fit in the same application.   ???
Jose Gomez
CLC Member #23082

Offline Lexi

Re: 1956 Generator bracket mystery
« Reply #3 on: May 11, 2019, 10:29:53 AM »
Thanks guys. Interesting to see that gusset is not present in Jose's picture. Often those illustrations are older than the model year so perhaps it was an earlier bracket or as Lou suggested intended for another product that used the same generator. Even with this steel one back in place the belts are still not lining up 100%, but is much better. When I first learned of this issue my thought was that the exhaust manifold on that side must be incorrect. Like, what else can it be especially as there is only one way the bracket mounts to the exhaust manifold and only one way the generator mounts to it? The MPL only lists one RH exhaust manifold for a 1956 Cadillac.

Some background, the engine in Lexi is not numbers matching. Someone changed it ages ago. As such, I had a spare engine rebuilt, also from a '56 Caddy, which enabled me to still drive and enjoy my car during the rebuild process. As Lexi's engine was not original to the car, I thought no harm done in putting another one in, as long as it is also period correct. So both engines were from donor 1956 Cadillac cars. When I bought Lexi I never received the block, so I was stuck just keeping her period correct.

Thinking about this problem had me check the engine unit numbers on both engines. That's the number at the back near the bell housing. The engine that came out of Lexi had the letter "K" in the number, but the rebuilt engine lacks that character and has an "X". The "K" stands for an AC equipped car. I would think that would be a guide for assembly line workers. However, could it also mean that if the engine unit number denotes an AC car, could the finishing of the front of the block been done differently? For example, perhaps the area where the AC bracket fits was machined differently? That would impact how the belts line up. My guess is no, but why I have this fitment issue is odd to start with. I guess what I am saying could there be a difference between "K" and "X" blocks that would impact this situation???

The Master Parts List suggests no, as it does not differentiate between AC and non AC blocks, rather it states that the "factory will stamp the engine number on the block when specified on order". There is no mention that a block will be finished differently based on whether the host vehicle will be AC equipped or not. Playing the devil's advocate the MPL is also not the place to discuss finishing procedures either. Car still at shop since the frame crack repair so it is bugging me that I don't have 24/7 access to it, (hence the reason I don't have a photo of the steel bracket). The mechanic was actually going to elongate the holes in either the steel or cast bracket to make it fit properly until they discovered that the odd steel bracket provided an acceptable mount, (but still not 100%).

Addendum to Authenticity Manual: Generator mounting bracket cast or steel??? Hmmm...

« Last Edit: May 11, 2019, 10:51:42 AM by Lexi »