W115 Flex Disc Replacement

[Kjhall65]

Today I replaced the front and rear flex discs on my W115.  Its not quite the same as the W116 but very similar and will give you a good idea of how easy this job is if you want to do it yourself.

Its common in these old mercs for the discs to get brittle and start to crack.  If left unchecked and the flex discs can let go and make a real mess of the car.

Here is the old girl up on the car stands ready for the job.  I usually leave a jack back and front as extra safety.  I'm not keen on the thought of being crushed under the car if it moves.


From what I understand the flex discs are pre-balanced so they must be installed in the same position as the old part.  It is important to mark up the old disc where it aligns with the drive shaft connector and the gearbox/diff connection before you remove it.

First step was to remove the bolts for the driveshaft centre support so that I could slide the drive shaft away from the old flex disc once the bolts were out to remove it.  Here is the front centre support.  The W115 has two centre supports.



Once the flex disc is removed mark the new one up with the old one as a template and install the new one.  The torque setting for these bolts was 45nm.

Here is the new front flex disc in place.


Here is the old front one.  As you can see it is badly cracked.

And the new one in the box.  The kit comes with new bolts and self locking nuts.


Once it is in place and the bolts are torqued up, don't forget to replace the bolts in the centre support bracket.

The rear is much the same but much more accessible.  Here are some pics of the diff spindle and the drive shaft disconnected waiting for the new flex disc.



The rear one was in worse condition than the front.  The cracks went right through the meat of the disc.


I finished up with a gentle drive around the suburb just to make sure all was in balance and there were no nasty noises.
Ken