Those who know what they’re doing need only simple directions: 1) remove shaft; 2) replace bearing. Maybe this will come in handy for those who haven’t tackled this job before. I’ve gone over my earlier posting and tried to include the latest helpful suggestions of others. Good luck with it!


Center Support Bearing replacement

The center support bearing lives above a crossmember at about the center of the car where the two sections of the drive shaft meet. The large rubber bushing which supports and isolates the bearing keeps it hidden from view. To get to it, at least the forward section of the drive shaft has to come out. Here’s a procedure for replacing the bearing which includes the option of removing the entire drive shaft, something which may be necessary if your universal joints need attention, too.

[Removing the entire drive shaft may make this an easier one-man job. If removal begins at the rear differential flange and the sections are re-assembled in reverse, one connection at a time, less weight will have to be lifted at once. If only the forward section of the drive shaft is removed, finally re-assembly occurs in one step but requires the coordination of several components at once: the rear end of the front shaft section, the forward end of the rear shaft section, and the large rubber bushing and spring correctly positioned in the crossmember.]

Start with four wheels in the air, transmission in neutral, parking brake off.

Before you loosen anything, find the splined, telescoping connection where the front and rear sections of the shaft meet. This connection is immediately forward of the center universal joint, but may be hidden by a small rubber bellows installed at the factory to protect the splines. Mark the two shaft sections where they meet so that you can get it correctly re-assembled. (Factory marks or marks from an earlier repair may be visible.) This is important in order to preserve the phase of the universal joints in relation to one another and the overall shaft balance.

If the plan is to remove the entire drive shaft, start from the rear and disconnect the shaft flange from the differential flange. When loose and pulled to the rear of the car, this rear section of the shaft will slide free from the forward section at the splined connection mentioned above.

While the drive shaft may look pretty massive and stout, it’s really just a hollow tube that’s not very heavy and may be easily damaged. Looks aren't everything. Anyway, easy does it with the drive shaft.

Leave the rear flange attached if planning to remove only the forward section of the shaft. The center support bearing assembly is held in place by a crossmember and four bolts. Loosen these, but before you drop the center altogether, make the forward section of the drive shaft mostly loose at the transmission. As you lower the cross member, notice the orientation of the small coil spring and cup washer supporting the bearing through the bushing from below. You will need these parts.

Once the shaft section(s) are out, have a good look at the universal joints. They should flex smoothly without binding. Excessive play is a problem. If they need attention, that would be another topic. [Here I would urge caution, as it's very tempting to invite a hammer into a discussion about universals and damage may occur. (Ask me how I know this.) Stick with the vice and socket approach.]

If the u-joints all check out, take the time to lube 'em up while they're out of the car--it's easier. If they're meant to be lubricated, your joints may have grease zerks or allen screw caps at their center axis. And while you've got the grease gun out, clean and relube what you can of that splined connection.

Before removal, make note of the bushing’s front/back orientation. The bushing will peel away from the bearing without too much trouble. While bushing failure does not necessarily mean the bearing has failed, it should be suspect. The center support bearing can be the source of a lot of mysterious driveline noise, so if you have any doubts about the condition of yours, consider replacing it.

Polish clean the exposed area of the shaft over which the bearing will have to slide to get off. Any junk still on the shaft when that bearing starts to move will soon be trapped between the bearing and the shaft, turning an easy job into a struggle. The bearing can be removed with a puller arrangement, or by judicious use of a vice, a drift, and a hammer. But clean it well first—we’re talking 600-grit clean—or you may soon wish you had a bigger hammer

Once the old bearing is off and the surface of the shaft is cleaned again, the new bearing can be driven on with a short length of the right diameter galvanized pipe and the same judicious hammer. [There are two different size shafts with bearings and bushings to match. Most (later) cars use the larger. The pipe has to be only long enough to clear the end of the shaft, and is to be applied to the inner race of the bearing while the other end of shaft is secured and protected.]

With the correct forward/rear orientation in mind, lightly lube the new bushing (I prefer undiluted dish soap) to get it over your new bearing and you're ready to put it all back together.



Which grease for the u-joints?

[Short answer: In general, for wheel bearings and universal joints, you're looking for a lithium-based grease, and there are many; molybdenum grease is preferred for CV joints. Long answer: see the Internet.]

It can be hard to know exactly which is the right grease to use in your universal joints, particularly when the grease packaging itself warns against mixing grease types. And even new joints with that light packing grease on the needle bearings need to be thoroughly grease-packed once installed. Making the perfect choice would seem to require knowing what type of grease is in those joints already.

Here’s an imperfect but workable solution: Pick a good grease and put it in. While there will probably be some admixing between the newly introduced grease and the old junk which gets squeezed out the seals, for the most part the new will displace the old. What you’re putting in has got to be better than what’s coming out. And it’s probably more colorful, too! If in doubt, let more come out.