Just completed this job on the 1982 300D this weekend, and I would like to pass along a few tips that might make the job easier for others.

First of all, the entire driveshaft can be removed without taking off the rear transmission support bracket or the emergency brake cable puller assembly. The manuals tell you to drop these parts first, but you don't need to do it - just slide the parts out the back of the transmission hump. I had the front of the car up on steel ramps.

Flex Disk:

These come with new nuts, bolts, and one washer for each bolt. So, the puzzle for me was to determine where the washers go. After researching in my manuals, it was determined that the washers always go on the side of the bolt (either the nut or the bolt head) that directly rests against the flex disk. The washers do NOT go on the driveshaft sides. Previous owner/maintainer did it exactly backwards. The six little bolt tubes in the flex disks protrude at bit - three on one side and three on the other. These must mate into the driveshaft sections - there are indentations for them.

As mentioned elsewhere, mark everything for exact reassembly - including the exact spline mating at the center of the driveshaft.

Bolts always push through the flex disks AWAY from the center of the car. So on the front disk they push towards the transmission, and on the back they push towards the differential.

Access to the front flex disk nuts is a little restricted. You can gain sufficient access with a wrench on the driver's side of the transmission. Passenger's side is more blocked by fluid lines. Hold the nuts with the wrench - access on the bolt head side can be accomplished with a socket wrench.


Center Bearing:

You need a puller with a six-inch reach. Typically not stuck on that hard, but you need a puller.

Go ahead and get a new bearing AND center support AND dust cover. I had previously inspected these on the vehicle and they looked good, but with the driveshaft down it was obvious the rubber parts were shot. So was the bearing.

You have to press the new bearing into the bearing support BEFORE you drive the bearing onto the driveshaft. I used a vise and big washers - no luck with a hammer and wooden block. What you DON'T want to do is drive on the bearing and then try to put on the rubber center support. There's a metal ring in the center support rubber that holds the bearing very tightly.

I was able to drive the bearing onto the driveshaft with a 1-1/4" by 12" long galvanized pipe "nipple" found at Home Depot. Yes they really do call it a nipple for some reason, Mr. Moderator. 1-1/4" TV mast will not work. I think the TV mast is measured on the outside and the pipe on the inside.

When you get the driveshaft pretty much in place and the flex disks bolted up, it's a lot easier to get the center support bolted up if you can support the weight of the driveshaft with a jack. Bolt the center support up last.

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Hope my experiences help someone else on this task.

Results were an elimination of a pretty good clunk when transitioning from "pedal down" to "pedal up" Rear disk looked good - front disk was cracked pretty good but not showing anything internal.

I still have a little vibration that seems to come from the center hump. It is either the transmission output bearing or the driveshaft U-joint. The U-joint was not dry, but seemed to have a center "detent" when moving back and forth in one direction. The U-joint doesn't seem to be made to be replaced due to two difficulties. The first is finding one the right size. The second is that the U-joint is pressed in and then the driveshaft metal deformed (straked is the word?) with something like a chisel to hold the joint sections in. U-joints really should be smooth side-to-side / up-and-down when moving.

So, if anyone ever does the driveshaft U-joint - we all need to know how you did it and where you got the parts.

I'll not take mine down just to do the U-joint unless it goes really bad, or the transmission has to be overhauled. It's not a hard job - I'm just am not enthusiastic about repeating it!

Ken300D