1956 AC Compressor Same as 1957?

[P. Manoogian]

Will a 1957 AC Compressor work/fit in a 1956 ?

[Big Fins]

It's an A-5 with the correct ports, right?

After that, it's the hoses and valves.

[J. Gomez]

Will a 1957 AC Compressor work/fit in a 1956 ?

Peter,

The short answer is "no" if you want to keep it original, the 1956 compressor has a larger pulley around 6 ¾" versus the 1957 with a shorter one around 5 ¾", also the valve assembly have different part #s.

Internally the compressors both have similar parts and they both have the same mounting areas.

[dn010]

The interchange manual states the 56 will interchange with a 56 Buick. If it is an early 56, it will interchange with a 55 Olds, 55 Pontiac or 55-56 Chevy. There is no interchange between years Cadillac wise.

[Big Fins]

The base compressor itself would work, you would only need to swap out the pulleys. Any hoses and valves are separate from the pump itself. Even if the pulley wasn't exchanged, the compressor RPM would just be a bit faster. It also may cool a little better at an idle. But you would have to source a smaller belt.

[J. Gomez]

The interchange manual states the 56 will interchange with a 56 Buick. If it is an early 56, it will interchange with a 55 Olds, 55 Pontiac or 55-56 Chevy. There is no interchange between years Cadillac wise.

Dan,

Correct the 1955 Chevy, Olds or Pontiac compressor are similar unit as the very early 1956 Cadillac which have spline shaft and clutch plate, although the valve assembly may be different for these GM models.

The base compressor itself would work, you would only need to swap out the pulleys.

Big Fins,

Well exchanging the pulleys between similar units is "easier say than it can be done". 

I'm refurbishing several compressors I have (1955, 1956, 1957 and 1959 or 1960 can't recall) and each unit with same layout one have to add/remove the correct rear and/or front shims at the clutch plate for the correct gap it, even changing the pulley bearing one needs to do the same process (front only). 

The work of adding or removing the shims to gap the clutch against the coil plate correctly is a PITA as you have to constantly remove and re-install the clutch.     The front shims is a bit easier as you just place the clutch inside the pulley (no need to insert them on the shaft) and add or remove the shims to get the correct gap.

[Big Fins]

I'll shut up then. I wasn't aware the A-5 was so complex of a unit.

[J. Gomez]

I'll shut up then. I wasn't aware the A-5 was so complex of a unit.

Big Fins,

You are in luck I just starter on my third unit (this one is a '56) and was able to take a few pictures for reference.

Picture 1 is the unit in the bench with the pulley and clutch removed, the coil is behind the plate. There is a front seal and an "O" ring inside the coil cover (held by 6 screws) I removed and inspected them before hand, so the picture was taken after.
PS The two other units on the floor are the ones already done (1957 with the small diameter pulley).

Picture 2 is the model # tag.

Picture 3 are the set of shims that are needed for the rear and front of the clutch. The rear ones I may need to add one (maybe 0.01") this side is the PITA as I need to check the gap with the clutch in and coil energized, the front one I know I would need more.

Picture 4 shows how to place the shims inside the pulley (above the bearing) and placing the clutch inside to check the gap, this one is much easier to do.

Picture 5 is the clutch front and rear (with the springs removed to check the nylon balls) pieces.

It is a time consuming process but as long as I keep a cold bottle next to the work area time is irrelevant.   

[Big Fins]

Jose', thanks for setting me straight on these. I've never taken the clutch assembly off of an A-5. They are much more complicated than an A-6, a York or a Tecumseh. If I ever get to delve back into a 50's car with A/C. I'll know who to send the compressor to.

I'll make sure to include a coupla cases of those cold bottles just to keep you interested.