[FWDLK] 1955 Chrysler 300 driveshaft and Murphy's Law
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[FWDLK] 1955 Chrysler 300 driveshaft and Murphy's Law



Murphy's Law ("If anything can go wrong, it will") was born at Edwards Air
Force Base in 1949 at North Base.

It was named after Capt. Edward A. Murphy, an engineer working on Air Force
Project MX981, a project designed to see how much sudden deceleration a
person can stand in a crash.

One day, after finding that a transducer was wired wrong, he cursed the
technician responsible and said, "If there is any way to do it wrong, he'll
find it."

Thanks to David Homstad on the Forward Look server for his response to my
query on driveshaft alignment and rear motor mount positioning.  He sent me
images of a Nov. 12, 1954 Dodge Service Bulletin No. D-3 that states the
1955 Dodge engines were set 3/4" to the right of center, cocked 2 degrees to
the right and 3 1/2 degrees down.  This was done to balance accessory weight
and permit lower drive shaft tunnels.  I can only assume the same thing was
done on Chrysler 300's.  Perhaps someone has a similar service bulletin for
Chryslers.  The bulletin goes on to say the horizontal connection angle at
the front U-joint should be 2 to 3 degrees and the vertical angle at the
rear U-joint is supposed to be 5 to 7 degrees, 5 preferred.

The bulletin states there is very little to affect these angles,
but...Murphy was an optimist.  Let me know if you want copies of the service
bulletin.

It appears the transmission support cross member on my car was removed and
reinstalled backwards at some time.  This puts the whole system immensely
out of line.  It does not appear to be possible to remove and reinstall the
cross member without dropping the exhaust pipes so we have elected to just
redrill the rear motor mount holes and shift it over to align the
driveshaft.  The exhaust system bolts do not look to be able to withstand
R&R of the exhaust pipes.

No significant vibration problems have been observed with the misalignment,
but the drive shaft and balancing weights did rub the tunnel in a couple of
places with four passengers in the car and that triggered the investigation.

Now, I'm told the gas tank on my car is not the proper one and as a result
the top was dented in by previous installers.  So, I am in the market for a
1955 Chrysler gas tank.  The Service Manual and Parts Manual agree that all
'55 Chrysler and DeSoto tanks are the same 20-gallon tank, except for the
T&C/Estate wagon.  Part number 1557470.  Any one having a good spare gas
tank for this vehicle please let me know price & condition.

Rich Barber
Brentwood, CA 94513

-----Original Message-----
From: David Homstad [mailto:dhomstad@xxxxxxxxxxx] 
Sent: Thursday, October 26, 2006 12:37 PM
To: Rich Barber
Subject: RE: [FWDLK] 1955 Chrysler 300 needs & questions

Rich,

I don't know about 55 Chryslers, but 55 Dodges did have unsymmetrical motor
mounts. I attached a copy of a 55 Dodge Service Bulletin on the subject.

Try measuring your cross member to see if the bolt pattern for the tranny
mount is centered in the frame, or which way it is off.

Dave Homstad

-----Original Message-----
From: Forward Look Mopar Discussion List
[mailto:L-FORWARDLOOK@xxxxxxxxxxxxx]On Behalf Of Rich Barber
Sent: Thursday, October 26, 2006 1:46 AM
To: L-FORWARDLOOK@xxxxxxxxxxxxx
Subject: [FWDLK] 1955 Chrysler 300 needs & questions

For my 1955 Chrysler 300, I'm looking for the passenger's side trumpet horn
and a pair of the bolts with special ends that are used to connect to the
straps holding the gas tank.  Time and modern fuel had kind of dissolved the
vent hose off the tank and it would leak out the vent when filled.  Unsafe,
not environmentally correct and expensive.

Question:
Is it possible the cross member that supports the rear motor mount is not
symmetric?  After removing and reinstalling the cross member to install a
new rear motor mount, I've noticed the drive shaft is not centered in the
front part of the tunnel.  The balance weights make a funny sound when
rubbing against the tunnel with four big passengers in the car.  I'm
wondering if my mechanic might have reversed the cross member.  The front
motor mounts do not appear to be deteriorated and I'm assuming the
driveshaft should be pretty much centered in its tunnel.

Any insights would be appreciated.  We'll take some measurements tomorrow,
but I'm real reluctant to just re-drill the cross member to center the
driveshaft.  I'm wondering if the motor mount itself might not be symmetric
and could have been installed improperly.

C-300'ly.
Rich Barber
Brentwood, CA

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