Replacing a 64 Wildcat Driveshaft Center Bearing Support
The procedure is the same for LeSabre and Electra

So, you have just pulled your 64 full-size car out of storage, or a junkyard, or off the rollback after a tow home. You put the car in drive or reverse, and get a definite clunk every few feet that feels like someone is taking a rubber mallet to the floorboard. That feeling is caused by a broken driveshaft center bearing support.

Buick used some neat technology in 1964 which included a cruciform (X) frame and a two piece driveshaft with a double universal joint in the center. Where the two pieces of the "X" frame meet, there is a hollow tunnel that goes through them that the driveshaft passes through. Within this tunnel sits the double universal joint, and in front of it is a driveshaft bearing suspended in a rubber bushing that is molded into a metal bracket. Over the years the rubber between the bearing and the bracket deteriorates, and after a rough experience such as a tow, hard slam into gear, the rubber gives way, and the driveshaft falls in the middle. With nothing to keep the driveshaft straight and suspended, it merely knocks around in the tunnel. This is neither good for the car or the driveshaft. Luckily, parts are readily available and the task of replacing the bearing can be accomplished in half a day.
 

Start by removing the four driveshaft U bolt nuts. I recommend a stubby wrench and plenty of patience. Once the nuts are removed, you can carefully remove the U bolts while supporting the driveshaft. You will be able to move the driveshaft forward and then let it carefully dangle or come to rest on the ground.

To the left you can see where I took a preventative measure to keep my driveshaft clean. There is dirt beyond the concrete pad I am working on, so I wrapped plastic bags around the end bearings to keep them from getting muddy. On the right, you can see the mound of dirt and general crap that came out of the driveshaft tunnel before the bearing. Wear safety glasses when working under a car! This is my first peek at what has been making the racket.

The picture to the left is a friendly reminder to put a pan under the output shaft of your transmission and put a plug in it. If not, you get an environmental problem. I seem to be the worst at remembering things like this, so I keep the kitty litter company in business. To the right, a close up of the issue. The rubber just deteriorates and one good jolt, and no more suspended bearing. 
 

Mark with chalk or marker exactly where each half meets each other before you take it apart. The driveshaft has a nut that has to come off so you can separate the two halves. It is a very large size, over an inch, so most non-professional mechanics will need to buy the $40 adjustable wrench that can handle it or beg, plead, or rent one. Be extra careful in a vise with a driveshaft! They are hollow tubes, and too much pressure will distort them.

This is the everything taken apart. Note to the left there is a metal ring that kiss the front of the new center support bearing. Lube these splines up gingerly while you have them out and make sure not to get abrasives embedded in the grease while you work.

Here is what you need to complete the repair. This is a Powertrain Industries 3R80-10 Center Bearing Support. It is listed with a bearing I.D. of 1.575, and mounting holes at 1.50 center to center. CARS, Inc. out of New Jersey sells them for around $90. I lucked out in that my local driveshaft shop had the part in stock. Should you prefer to order the part from another vendor, contact Powertrain Industries for a dealer near you. Mine did not come with a bearing. You can reuse your old one if you like, but I purchased a new one from a local auto parts chain. It is BCA bearings X908CC, the same maker as the OEM bearing. It is around $60 as of 2006.

To the left is how I installed the new bearing in the center support. After removing the included bearing retaining ring, I pushed the bearing into the support. Then, I cut a small ring of 2 inch PVC conduit that fit the bearing almost exactly. I then put a small mallet on top of the ring, and then hit that mallet with a larger mallet. The bearing seated, and I was able to install the bearing retainer, but I found out later this was not enough. The bearing would produce a shrill sound which subsided when I took the whole nine yards to the driveshaft shop which found the bearing needed to be seated 1/8 more to be perfect. To the right is the new bearing installed.

As I previously mentioned, I had to take the driveshaft to the  shop because I was getting a shrill sound from the bearing. While it was there, I had it balanced. It took the two weights on the one end, pictured at the right, and it took one weight on the other end. It was around $50-$60 to get the shaft balanced.

 
Once you are done with the bearing, the driveshaft goes back in just like it came out. Once it is seated in the transmission, you will adjust it out until the center support nut holes are visible through the tunnel holes and secure the bearing. After that, reattach the rear U-bolts, and go for a drive!