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331 Cadillac Main Seals

Started by PeterC, November 28, 2016, 02:12:06 PM

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PeterC

Newbie here so apologize if this is a repeat or boring question -

Hoping I can replace front and rear main seals for my 331 CID Cadillac while in the car - assuming I can drop the pan in car ....  would this be possible? Also  - has it been concluded that a more modern seal is more effective than original rope seals or do most of you stick to the rope?

In the interest of full disclosure - the 331 sits in a 1939 Ford Coupe backed by a 1937 LaSalle Transmission

Thank you.
PeterC

Jay Friedman

Yes, you can replace the front seal in a 331 motor without removing it from the car.  The radiator must be removed first, then the crankshaft pulley, next the vibration damper and finally the timing chain cover, which holds the seal, must be removed.  Since it's in a Ford, there may be problems you would not encounter in a Cadillac, but I don't know what these might be.

And, yes, you can replace the rear main bearing seal on a 331 Cadillac engine without removing the engine from the car.  (You don't touch the transmission, either automatic or stick shift.)  It's best to use a Neoprene seal which can be purchased from Terrill Machine Co., Deleon, Texas and not a rope seal.  However, since the engine is question is in a 39 Ford and not a Cadillac, I can't tell you whether you can drop the pan with the motor in the car or not, which you can do in a Cadillac. 

I can send you an illustrated article on how to do this job if the motor is in a Cadillac; it would be up to you to figure out how to drop the pan in your Ford.  Since I don't know how to post the article on this web site, email me at jaysfriedman@yahoo.com and I'll reply with the article as an attachment to my email.  Alternatively, you can look up the article at 1949Cadillac.com  Let me know which you'd like to do.

Jay
1949 Cadillac 6107 Club Coupe
1932 Ford V8 Phaeton (restored, not a rod).  Sold
Decatur, Georgia
CLC # 3210, since 1984
"If it won't work, get a bigger hammer."

PeterC

Jay
Thank you for your response- will send you an email so you can provide that article-much appreciated!
PeterC

55 cadi

Actually if you look up past posts I started a thread asking about it and a few chimed in stating you don't need to remove the radiator or crankshaft, just need to move the trans back a few inches.

And there is a rubber seal made for that motor in place of the ropes, Terrel machine in Texas has it, think I have seen on eBay also.
1955 Cadillac sedan series 62
1966 mustang convertible w/pony PAC, now in Sweden
2005 Cadillac deville

Jay Friedman

#4
When I wrote the crankshaft pulley, the vibration damper and the radiator must be removed, I was referring to removing the FRONT crankshaft seal which is in the timing chain cover. 

As far as the REAR main bearing seal is concerned, there is no need to move the transmission back to change it on a 49 Cadillac 331 motor and probably later years of 331s up to about '55 .  I don't know one way or another about other years.  I've done it twice on '49s: once with CLC member Art Gardner on his car and the 2nd time with another friend on my own car. 

You must first remove the starter, the oil pan, oil baffle, oil pump and then the rear main bearing cap.  The key is to loosen somewhat but don't remove the screws on the four front main bearing caps so that the crankshaft drops down a few thousandths of an inch to ease upward pressure on the upper half of the old rope seal.  You then partially screw a wood screw into one side of the existing rope seal and press a brass punch (brass so you don't scratch the crankshaft journal) against the other side of the seal.  You grab the screw with a pair of pliers and pull, while pushing against the other side of the upper half of the seal with the punch, and it will come out.  You just pull the lower half of the seal out of the bearing cap.  Once both halves of the seal are out, you can easily install a new neoprene seal which doesn't require the careful trimming necessary on a rope seal.  Art Gardner wrote a detailed, illustrated article on how to do it, including the only really tricky part which is trimming the new oil pan gasket.  I'd be glad to send it to anyone who wants to read it.
1949 Cadillac 6107 Club Coupe
1932 Ford V8 Phaeton (restored, not a rod).  Sold
Decatur, Georgia
CLC # 3210, since 1984
"If it won't work, get a bigger hammer."