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The jury is back and it seems the front clip must be clipped. Once can simply not slide an object mounted on 1 1/2" studs into a space only 5/8" deep and have it come free from the studs.

I have by means of some small violence gotten the packing nut to back off and will try just repacking even though the shaft is none too smooth. If that does not seal up to the owners satisfaction I will simply decline the job.

Just wondering if the pump is a separate assy on the twelve as it is on other engines. Didn't see a pump assy listed for a 1607-08 chassis or other year twelves unless there is a separate parts manual for those engines. Curiously, of all the pumps listed for the 35-41 models in the manual only the 39 1703-3A- 5 chassis cars called for studs. Any idea why or what was different on those engines?

Yes, the Twelve pump is a separate assembly. Not too different in concept from the Eight/Super Eight pump used on the 320/385 engines, though much longer in length. I'll look for a picture.

As to the use of studs, the pump used from introduction thru 1939 on the 320/385 engine uses a locking ring secured by nuts on studs to secure the pump body to the block and yet allow rotation for belt adjustment (on models with timing chain_driven generators). The pump body is an eccentric so rotating the pump body within the block changes the effective distance from the crankshaft and is thus the means of adjusting the fan belt(s). The pump to block seal is a very large copper ring gasket.

Would this place be any help,
packardtwelve.com/

Or what about the gentleman from Houston who wrote a book about restoring a Packard 12?

Or, The Production Packard: A Restoration Reference 1935-1937, by Dar Kuehl? OK it won't help since the car is a 1938.

Ross,
I still have TwinUltranatics😀😄😆

Hello Ross, My 1608 Twelve has bolts not studs holding the water pump on. I shall have to check the parts book. The pump is not rotatable as it uses the externally mounted generator to adjust the fan belt tension. I have checked the parts book and it is supposed to be studs, 4 long, 2 short. My water pump studs have apparently been replaced with bolts at some stage. I checked my 37 Super and it is studs and I replaced the water pump a few weeks ago without difficulty, but there is juuust enough clearance. I would still hope that there would be just enough clearance to remove the Twelve pump with the blades off, and there appears to be a bearing retainer nut which may come off to reduce the length of the protruding shaft. I don't have a spare pump to check this out. Sorry. I still cannot imagine a front clip removal to change a water pump. Peter

The bullet has been dodged for the moment--I was able to finally get the packing nut out and get some new packing in even though the shaft is somewhat pitted. Leakage is now down to an occasional drop instead of the former torrent.

If the unit were not mounted on studs it might just be possible but still unlikely.

New question: Is the system supposed to be pressurized? It is equipped with a nice looking pressure cap of unknown capacity. Can't find any specs that mention if it is supposed to have that or not.

No V-12 or 320/384 engines have a pressurized system. The V12 has an overflow tank mounted on the RH frame rail. If fluid overflows, when the system cools the excess fluid is siphoned back into the system.

Twelve water pump

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"Just wondering if the pump is a separate assy on the twelve as it is on other engines. Didn't see a pump assy listed for a 1607-08 chassis or other year twelves unless there is a separate parts manual for those engines. Curiously, of all the pumps listed for the 35-41 models in the manual only the 39 1703-3A- 5 chassis cars called for studs. Any idea why or what was different on those engines?" Howard/HH56

Howard,

You seem to be referencing the 35-41 six/120 and 39 Su 8 parts book, that's why you can't find the V12 water pump.
There is a separate parts book for 37-8 Su8 and 37-39 V12.
All is illustrated and detailed in it

I have removed the studs on other old machines that used them to hold the water pumps. Replacing the studs with bolts makes future work so much easier. I wonder if removing the studs with the water pump in place is possible? I know that this would be a departure from stock, but for a driver, it would be a better way to go. Ernie, caretaker of the 1949 288 Deluxe, 'Miss Princess'.