1966 A/c Compressor Belt Size and Routing

[Robert Green]

Hi All,

I'm replacing the engine belts on my '66 Eldorado; it's an a/c non California car. The alternator drive belt had snapped so it seemed sensible to change everything else at the same time.

I ordered a replacement set from Caddy Daddy and have noticed that, in the case of the replacement belt for the a/c compressor drive, there is a significant difference in size from the belt already on the car.

My existing belt has a size code of 15560 with an outside circumference of around 56.7inches, and is routed to spool over both the water pump/fan pulley and crankcase pulleys as well as the compressor.

However the Caddy Daddy replacement (size code 7435) has an outside circumference of only 44 inches odd, and would I guess only spool over the front groove of the water pump/fan pulley, leaving the front groove of the crankcase pulley unused.

The Cadillac shop manual doesn't show belt routing or specify belt dimensions (as far as I can see), and Rock Auto list both the longer and shorter belt sizes for the '66 a/c compressor belt.

So which is the correct belt size and routing?

Also if anyone has experience with the different belt brands I'd  very interested to hear.

Many thanks,

Robert Green