Driveshaft Center Support Question - PICS
 

84D. I was going to work on replacing the driveshaft center support on the weekend but I didn't have a large enough open wrench (1 3/4? & 1 5/8?) to loosen the shaft nut (Recently noticed shuddering/vibration at low speeds.) Found the rubber bushing in rough shape.

So, am going to have the wrenches today and try it tonight. I do have some questions if those who have done this work can verify my observations and give me some pointers.

From what I've seen so far, to change the center support bushing & bearing, I don't think I need to remove the front half of the shaft. Just unscrew the shaft nut to remove the rear half of the shaft?

Is the reason for unscrewing the shaft nut because it holds the spline in place? Also, is a puller necessary to remove the bushing/bearing?

I also plan to replace the tranny support while I'm down there. Thanks...:)

Adding pics below......... got the sleeve nut loosened. Now waiting for center support...

You can just remove the rear part but you need to make sure you mark it before you split it to go back the same way.
You don't need any kind of puller but will need a good hammer.
The nut does hold the splined section together.
47 mm comes to mind on the size.

For the large nut you can use lock plyers or channel locks. Yes you are loosening the nut to shorten the driveshaft to pull the drive shaft out of the spline.
Mark the drive shaft for orientation. It is balanced and needs to be reassembled in the correct orientation not 180 degrees out.

Take the whole driveshaft out so you can work on it easier. And mark it for orientation.

You will need a puller for the center bearing.

Check your flex disks while you are there.

Dave

Thanks, Jim and Dave....

I looked at the flx discs closely and they both appear to be in very good shape. Can't say if they have been replaced b4. I thought about replacing but the front one appears to be a PITA to get at.

Thanks for the confirmation. I always like to understand a mechanism b4 messing with it.

I believe there's a lock ring washer somewhere that also needs to be removed.

Thanks again and please post if y'all think of sumthin' else..:)

George,

There is a lock/snap ring you need to remove to get the bearing out. Using the puller depends if the bearing is stubborn or not.

I know it is a PITA, but I only pulled the whole shaft out. But I guess you can slide it out of the spline. To get the drive shaft out you need to remove the mount and since your are replacing the mount you can get at the flex disk just use a "flex" socket and you should be able to get at it.

Good Luck.

Richard

Dont be surprised if you dont find one. Mine did not come with one. You will also need something to put the bearing in place. I think i used a 6" 1 1/4 pipe to put mine. It was somewhat crude. Others might have an idea to set the bearing. Mark the 4 flanges. They should be assembled exactly the same way you took them out. Use white paint.

Thanks RM
 

Glad you said it... that the tranny mount has to be removed to get to the front flex disc. Seemed like about the only way I saw to do it.

Still thinking am not gonna mess with the front FD since it looks pretty good.

Good point on the bearing. They got to be pushed in evenly I presume.

By flanges, are you referring to the back end of the driveshaft that connects to the flex disc?

BTW, I believe there is no need to remove the rear flex disc either, right?

Yes, sorry. I dont know what the ends of the drive shaft is called. If you are not removing the flex plates, just mark the position of the driveshaft and flexplate. I dont recall it anymore but I might have marked the position of the front to back driveshaft too.

Dave, by orientation, are you simply referring to marking how the front and rear shafts line up so you insert it back the same way?

At present, I have loosened the sleeve nut and removed the rear flex disc bolts and was trying to get the rear shaft off the flex disc but it would not budge. Thats why I decided to remove the front shaft also.

As you suggested I will remove the entire DS instead of just the rear one. It sounds line this is the best way especailly with ensuring that the spline goes in properly.

I will be removing the tranny mount (since I'm replacing the mount anyway) to gain better access to the front flex disc.

Any more suggestions are appreciated.

http://i158.photobucket.com/albums/t...p1010141-1.jpg

I just changed the flex disks on my 210. I have a pry-bar which is made for hammering on the handle. Put that bar on the metal insert, just below the tri-star drive and give it a few taps. The metal inserts go into this tri-star drive and like to stick into place. They come out easily, but tapping seems to be required. Prying on the rubber didn't do it.

Loosening the large nut allows the drive shaft to separate. A front piece and a rear piece. The splines that are talked about are how the drive shaft attaches. One is larger than the other and the smaller slides into the larger one vie splines or front to rear grooves that prevent the front and rear shafts from rotating while installed.
When the driveshaft is made it is balanced with weights. If you install the drive shaft not using the same splines then it will be out of balance.
Look at the attached exploded view diagrams and you should be able to figure it out.
So to summarize. Mark the dirve shaft so that you use the same spline holes when assembling the dirve shaft. YOu will have to be accurate 10-20 degrees of rotation.

Picture 1 and 2 are a gas W123 driveshaft. The 3rd picture is the diesel driveshaft. 4th picture the center section exploded view.

Dave

I did mine last week (80 300td)and didn't have to touch the sleeve nut. I removed all bolts from my front flex disc and pulled the (well marked)front section of the shaft forward out of the spline and out of the car. I didn't take out the ebrake linkage as I wanted to keep the car from rolling off the ramps and on me. I left the rear flx disc on the diff but removed the three bolts that attached the disc to the shaft. With the two bolts out of the support, the rear shaft easily came out rearwards. The support took a while to pound off the bearing, I used a heavy hammer and a chisel and kept knocking till it slowly came off. The old one made the perfect tool to pound the new one on. Do not mung up the splines. As mentioned be careful, to match them up correctly, mine only wanted to go back the right way, I put fresh grease on the spline. My front disc was shot as was the support but the rear disc was fine. It was helpful to roll the car three feet to rotate the shaft to make the last flx disc bolts accessible.

All that horrible vibration is smooooth.
Good luck.

Thanks, Fellas.... Ok, I got it on lining up the splines...

I'm actually in the middle of doing this job.... just taking another break and checking the forum...:)

From what I'm reading here, your driveshafts are coming off easy off the discs. I have the shaft-side bolts of the front flex disc off, all of the rear flex disc bolts off and the sleeve nut loosened but my driveshaft does not seem to want to budge at all:( . I'm just trying to budge by hand right now.

Use a deadblow mallet. Or a wooden mallet if you have one. Last resort, a hammer with a piece of wood to prevent damage.

Dave

Matt, by tristar I assume you are referring to the end part of the shaft. Not sure what you mean by "metal insert" and also the "rubber".

I'll use the rubber mallet and see what happens.....

Ok, got the rear flex disc to pop off.... but now can't seem to get it to move forward enough past the pinion? so the shaft comes off.... pics...

I realize now why the flex disc kinda gets stuck... its because of those metal (bronze?) inserts in the discs that fit into the tristar that help hold the disc in place...
http://i158.photobucket.com/albums/t...P1010149-1.jpg
http://i158.photobucket.com/albums/t...l/p1010147.jpg

Make sure the driveshaft nut is really loose and see if the driveshaft will collapse any more so that you can remove it.

Dave

Thanks, Dave.... I'm just taking my time on this project.... but I wan't to get it done hopefully in the next few days since its taking up one space in the garage... the pinion shaft is much longer than I thought. When I get in to stuff the first time, I approach it a bit carefully so I don't mess anything up. Hence, the apprehension on just whacking things.

I'll fully loosen the nut when I get back in to it. I actually partially screwed it back on thinking that it would help pull the rear shaft forward but looks like that did not accomplish it.

Thanks for the help. I'm sure I'll be asking for help again:) :)

Rich, hopefully its still fresh in your mind... how much pushing forward of the driveshaft did you have to do to get it free from the pinion shaft (the stubby shaft coming out of the differential). This thing looks like its sticking out about an 1 1/2 inches..

So, as you can see, I have not lowered the shaft yet so have not gotten to the snap ring. The tranny mount is off but am not putting it back on till the shaft is back on.

Thanks for the help...

Center bearing
 

Love the pic of Toby

The drive shaft is something of a tight fit. Did you remove the center mount? I had to remove the parking brake in order to allow the drive shaft to flex enough to make it in or out.

Since this started as a vibration issue, let me make a suggestion. This comes from experience. When you have the driveshaft out, check the u-joint for a notch. Move the joint slowly from side to side to see if it has a notch in the centered position. Test both axes of rotation. If it does have a notch, you will need to replace the entire shaft, as the (bad) u-joint is pressed in. The vibration you were feeling, and a busted mount were exactly what I witnessed on my car. If it is notched return the new bearing and mount, as the new driveshaft will come with them.

You can remove the flex disc without removing the tranny mount. Your choice.

Thanks. Yes the mount is off. It will be replaced when I'm done. I'll attempt to lower the shaft again next time. From what i can see I don't think its necessary to remove the prkg brake but we'll see.

I don't exactly know what you mean by notch. Are you referring to a mark of some type or a lateral play on the u-joint? I believe the vib is caused by a degraded center support. The rubber is pretty broken up. I'll take a pic of it when I have the ds off. I'm praying its not what you had:)

Thanks so much for the suggestions...

Feel the notch
 

Sorry for not being clear. The notch is something that you hope you cannot feel. As you slowly move the joint on 1 axis/hinge, from side to side, you MIGHT feel a detent, catch, or notch in the joint, near the center. It will be very soft. Mine had the same symptoms, and I went through the same set of repairs. I had a bad transmission mount, and bearing support, that were easy to visually confirm had failed. Don't know the order of failure, but the end result was that all 3 (driveshaft, support, and tranny mount) had to be replaced.

If you can get the driveshaft off of both front and rear flex discs, then there is no need to remove the parking brake. This is only necessary if you think you have to force something, as the extra space will allow you to bend the shaft enough to 'shorten' it.

Mercury is a boxer

Kababayan, I see what your problem is. When I removed my driveshaft, I had the differential lowered a bit. This allowed space to get past yoke pin. But since you are not touching the differential. What you need to do is push the driveshaft back into the yoke to its orginal position. Then your going to have to disconnect the shaft from the transmission end. There is no pin there so you can easily slide it out. Once you have it disconnected from the transmission side, you can move the driveshaft forward to clear that pin.

Good luck.

Finally..
 

... got the drive shaft off. Had to remove front FD in order to slide out the rear end of DS from pinion shaft....

Center bushing was falling apart... No play or "notch" on U-joint. I actually don't know what notch means.... but no play or lateral movement at all. Vibration had to be from bad bushing... will rent a puller from AZ tonight and pull off bearing...

http://i158.photobucket.com/albums/t...l/p1010163.jpg
http://i158.photobucket.com/albums/t...l/P1010162.jpg