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Pelican Technical Article:

Flex Disk Replacement

Steve Vernon

Time:

3 hours3 hrs

Tab:

$25 to $200

Talent:

**

Tools:

E12 Torx, 18mm wrench, T60 Torx, floor jack

Applicable Models:

Mercedes-Benz C350 (2008-14)
Mercedes-Benz GLK350 (2010-14)

Parts Required:

Flex disk kit

Hot Tip:

Put a piece of wood between the jack and transmission

Performance Gain:

Get all the power to the ground

Complementary Modification:

Check your transmission mount

If the automatic transmission in your W204 is starting to change gears a little harder, or you are getting a vibration through the transmission or center tunnel while driving, your flex disc may be deteriorating. This W204 has two flex discs that connect the transmission to the driveshaft and the driveshaft to the differential. These units will wear out over time and even if you are not noticing any signs of trouble, they should be inspected every year. The discs are made out of rubber and are designed to absorb some of the shock from the drive train. Like anything rubber, they dry out, crack and will eventually fail. If you let the discs get to the point that it completely fails while the car is in motion, they can cause a tremendous amount of damage.

The hardware on the flex disks are considered to be single use only, make sure you check when ordering that your kit includes all new hardware.

To change the mount you will need to safely raise and support the vehicle. Please see our article on safely raising and supporting your W204.

With the vehicle safely raised and supported, you are going to want to support the transmission as you need to remove the transmission mount to change out the forward flex disk.
Figure 1

With the vehicle safely raised and supported, you are going to want to support the transmission as you need to remove the transmission mount to change out the forward flex disk. Place a piece of wood between the jack and transmission to help support the load and then take the weight of the transmission on the jack.

The forward flex disk is located up under the transmission mount (red arrow) and you need to remove the mount to change the disk.
Figure 2

The forward flex disk is located up under the transmission mount (red arrow) and you need to remove the mount to change the disk. Please see our article on transmission mount replacement for additional assistance.

With the mount removed you will want to remove the mounting bracket from the transmission (red arrow).
Figure 3

With the mount removed you will want to remove the mounting bracket from the transmission (red arrow). Use an E12 Torx and remove the four bolts holding the bracket (yellow arrows).

With the bracket out of the way you can get access to the flex disk (red arrow) and the hardware.
Figure 4

With the bracket out of the way you can get access to the flex disk (red arrow) and the hardware. Note that the nuts on the bolts always face away from the drive shaft and towards the flange from the transmission or differential.

Make sure you have the proper tool for working with the hardware and in this case it is a T60 Torx.
Figure 5

Make sure you have the proper tool for working with the hardware and in this case it is a T60 Torx. You do NOT want to strip these bolts out as cutting them out is absolutely no fun.

Use the T60 Torx (red arrow) and an18mm wrench (yellow arrow) and remove all the hardware.
Figure 6

Use the T60 Torx (red arrow) and an18mm wrench (yellow arrow) and remove all the hardware. The driveshaft will tend to spin so use the parking brake to hold it in place if needed.

If your old flex disk looks like this when you remove it you waited way too long to change it out.
Figure 7

If your old flex disk looks like this when you remove it you waited way too long to change it out. Inspect the disk once a year and replace it long before it looks like this

Changing the flex disk on the rear of the shaft or the differential is the same as the front disk, with the exception that nothing is in the way.
Figure 8

Changing the flex disk on the rear of the shaft or the differential is the same as the front disk, with the exception that nothing is in the way. Again make sure that the nuts on the bolts all face away from the drive shaft and towards the differential (red arrow).

Use the T60 Torx (red arrow) and an18mm wrench (yellow arrow) and remove all the hardware.
Figure 9

Use the T60 Torx (red arrow) and an18mm wrench (yellow arrow) and remove all the hardware. The driveshaft will tend to spin so use the parking brake to hold it in place if needed.

Pry the old disk off and install the new one using new hardware.
Figure 10

Pry the old disk off and install the new one using new hardware. I always install the disk on the output flange first and then the driveshaft. Installation is the reverse of removal.

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Comments and Suggestions:
alaric Comments: Hello.whats the torque specs of the flex disk bolts on the W204 Merc C200.YEAR 2009
thank you
September 20, 2017
  Followup from the Pelican Staff: I don’t have torque information.

I would suggest you grab a repair manual, you should own one. It will have the procedure, special tools and torque specs.

Give our parts specialists a call at 1-888-280-7799.
- Nick at Pelican Parts
 
Jwa3000 Comments: My vehicle is a 2009 c350. I don' have a picture because I put it back together. It looked exactly like the picture in Figure 6 with all the bolts out. I just could not get the driveshaft to slide toward the back of the vehicle like I would have expected. I assume there is something else I need to loosen.
June 26, 2017
  Followup from the Pelican Staff: if all disc bolts are out it should move. If it doesn't the disc may be stuck on the shaft. - Nick at Pelican Parts  
Jwa3000 Comments: I'm trying to replace the front disc and the instructions are great but I cant separate the drive shaft from the transmission. I'm afraid to pry them apart because I might bend something how do I separate the drive shaft?
June 25, 2017
  Followup from the Pelican Staff: What vehicle are you working on? Can you share a photo of where you are at right now on the job, photo of the driveshaft? - Nick at Pelican Parts  

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Page last updated: Sat 10/21/2017 03:03:20 AM