Greetings,

I've ordered (from Phil) both flex disks and the center support bearing for my '90 300D 2.5L Turbo. I've read the DYI and posts I can find but have a few quick questions.

I'll be using jack stands. Is it better to jack up the front, rear or side to do the job?

Any advice on whether to do the front or rear flex first?

I've noticed that I should mark the orientation of the shaft before and after the disk. Any comments on that?

In some threads I've read about removing a heat shield. I didn't notice one the last time I looked.

Should I do the transmission mount as long as I'm doing the rest?

Thanks.

to replace the Center Support Bearing.
(Mark BOTH front and rear portions of the Prop Shaft,in relationship to each other.)

Scott98 has the Basic driveline bearing R+R documented for the W123 which
is most helpful for the W124 as well:

How to replace the driveshaft support (carrier) bearing - A step by step guide

AND

Bodhi has both your Travail(S) extensively documented!

See:

A subframe question (just the beginning ...)

Mark the Transmission,Propeller Shaft and Rear End attachment points for the
Flex Discs.(In relationship to each other).

Orient the Flex Discs properly as to Fore/Aft orientation.

Inspect the Centering Bushings at each end of the Propeller shaft for wear.

The flex discs you can do with ramps.
(one Disc at a time,if you wish)

To do the Prop Shaft, Safely, I'd get the whole chassis up on ramps.

Lifting one Side of the Chassis is Inherently Un-Stable and should only be
used for Emergency Roadside Tire Changes in which No Portion of the Operator's Body is under the Chassis.
The Factory Jack IS An Invitation to The Ministrations of E.M.T.s
(MUCH TOO Unstable for use ANYWHERE!!!)

Jack Stands should always be Supplemented with Emergency Backups
,Such as Cross Stacked 6" by 6"s so as to leave minimum 18" Safety Clearance.

There is an exhaust heat shield.

How old is the Tranny Mount?
[If I'm under there,and it's been more than 100K miles since Hamburg,it's gonna be replaced.]
(For that matter have you measured the Engine Mounts for "Collapse" ?)

When you ordered the Center Support Bearing,did you also order the
"Rubber Mounting Unit" #124 410 07 81 that the Bearing rides in ?
(Picture is of the Center Support with the Bearing already installed.)
(Bearing is Yellow [Rubber Seals] With Stainless Inner and Outer Coverings)

There are also two "Protective Caps" that fit onto the Center portion of the
Propeller Shaft:
#107 411 02 96 (Rear)
#123 411 00 96 (Front)

And a Protective Rubber Cap over the Driveshaft nut #202 411 04 97

Attached Thumbnails

 

__________________
'84 300SD sold
124.128

I'd never want anyone under a car supported by a jack.

I have some 10" x 14" blocks of wood. I was proposing jacking up the driver's side, putting two stacks of wood blocks at the two jack points and then resting the car on them.

I don't have ramps or jack stands and was trying to not buy a complete set. I knew a guy with a lift but that connection has closed so I'm back to using my garage floor.




I sent my request to Phil and he gave me the following list -

Front flex disc 1244100615
Rear flex disc 2024101315
Center support 1244100781
Center support bearing 0089814325

I'll speak with him Tuesday and mention your comments.

I did the motor mounts within the year but the tran's mounts are still original.

I was thinking that if I'm doing all of this work underneath the car that I'd like to get it all done at one time; 2 x flex disks, tran's mount & center support bearing.

I did a search using flex disks and w124 but did not find the links you provided.

Thanks.

Links work now.

AND:

driveshaft center bearing on W124??

AND:

Removing the center carrier support without the jaw tool

__________________
'84 300SD sold
124.128

Thanks - very helpful.

Not sure what is meant by coupling nut or if I'll need to buy a 46mm socket.

In this posting John talks about needing a new nut but I'm not sure it is applicable -

Drive Shaft Pulled out of the Transmission on the Freeway....

And here is the best posting I could find on doing the transmission mount -

Transmission Mount

Thanks for the help.

John's referring to the single Large Nut that secures the Output Flange to the
Transmission Drive Shaft.
Viewed from behind the Transmission (As if you were the Front Flex Disc)the
Output Flange has Three Ears with Machined Holes.
The Front Flex Disc's Three Bolts attach through the Output Flange's Ears.

Unless you've got a Boogered Output Shaft Flange (Likely cause could be
Imploded/Exploded Front flex Disc) ,There's No reason to fool with the Nut.
In the Second Pictogram #120 is the Output Flange Nut and #110 is the
Output Flange on the output shaft of the Transmission.


The "Coupling" Nut referred to is in the Middle of the Propeller Shaft and you'll
have to deal with it in your R+R of the Center Support Bearing.
#107 in the Pictogram is the "Coupling" Nut
#149 is the Nut's Rubber Dust Boot.
#137 is the front Protective Cap (Metal)
#134 is the Rear Protective Cap (Metal)

# 110 and 125 are the "Centering Bushings" in each end of the Propeller Shaft.

[From Bodhi's Travails we've learned the Bushings CAN be an Absolute Mother to remove]

Pictogram(s) Courtesy of: Клуб Мерседес Бенз России

Attached Thumbnails

   

__________________
'84 300SD sold
124.128

Regarding nut #107 do I want to obtain a 46mm socket or an open-end wrench?

Regarding bushings #110 & #125 I've tried to make progress through much of Bodhi's 11 page posting but do not see specific references to them.

Phil had not mentioned examining them or replacing them. How do I determine if they need to be replaced?

Jim's talking about the Pictograms Below.

Pretty much self explanatory.
(Numbers in the right hand column denote how many necessary Per Chassis)

Once Again Pictograms courtesy of:
Кузены Клуб Мерседеса Бенз России

Attached Thumbnails

   

__________________
'84 300SD sold
124.128

Crow's Foot for 1/2 inch Torque Wrench.
(Countered with Large Channel Locks on the 41MM shaft flats.)

Unless the Receivers in the Propeller Shaft ends or the Bushings themselves
LOOK buggered I'd leave them be.

Attached Thumbnails

 

__________________
'84 300SD sold
124.128

OK

I'll get the crow's foot and be ready.

Thanks for ALL your guidance.

It helps.

PS - It looks like I'll leave the front wheels on the ground and put jack stands under the rear.

The FSM assumes the Chassis is at "Road Ready" state when the Coupling Nut
is Torqued to the Specifications in the Manual.
[I.E. "Flat on the Ground" (Or a Lift) ]

A. Dalton cautions us to "Roll the Chassis Back and Forth, by Hand"
(to "Settle in" the Propeller Shaft Length)
Before Torquing the Nut.

'Better Wrench Turners than Myself,have Opined that raising either end of
the Chassis BEFORE the Coupling Nut is Torqued changes the Propeller Shaft
Length.

Just how large a Catch22 type Conundrum is this ???

If Y'all wanna get Really Cajun Crazy,think about how much New VS Old:
Subframe Mounts
"Pumpkin" Mounts
and Rear Control Arms
CHANGE the Propeller Shaft Length (When it's R+R ed)?????

__________________
'84 300SD sold
124.128

I did see those remarks in some of the posts.

I was thinking of hand-tightening the nut, taking the rear-end off of the stands, rolling the chassis and then raising as little as possible to get underneath and tighten it up.

It's just a thought - I don't know the best answer.

I'll be calling Phil tomorrow morning to order the tranny mounts and ask him about the three protective caps you mention in your 05-28-2011 12:40 PM posting. I'll ask him about how to properly tighten the nut. He may suggest I call Roy.