I recently replaced the rear axle bellows on my 64 230SL with a split bellows. It took two attempts to complete the operation- next time I would be much quicker.
I was working with the car on jack stands which made access to the work area a bit more difficult.
Before starting I checked the forum and the technical manual. Some information is available but I did not find any clear procedure. Hopefully these brief notes will come in handy for someone.
The most difficult part of the job is insuring that the mating surfaces of the boot meet properly so that a good seal is attained while working in a confined area. I did not remove the compensating spring as recommended in the BBB but did remove the fuel tank.
The bellows requires 9 clips. I ordered 5 new clips figuring that I could reuse some of the originals. I was able to reuse all of the original clips so I did not need the new ones nor did I need the special clip pliers. I used long nose pliers to crimp the clips. I initially intended to use silicone seal on the mating surfaces but was concerned that the sealer would pick up dirt while getting the bellows into position so I put it together without using any sealer and was able to get seal.
The basic procedure evolved as follows and applies specifically to the 230SL. Other W113 models are probably similar:
1. Set the car on jack stands- extra points for having access to a lift.
2. Remove the fuel tank.
This is optional but it is an easy, quick operation and allows a lot more working clearance.
3. Place a jack under the end of the swing axle and raise it so that it is level (more or less) with the differential.
4. Remove old bellows- clean up working area
5. On the bench: Mate the two edges of the bellows and pre-bend the ends of the clips so that they have a slight hook on the ends and will hold slight tension on the mated boot. Remove clips without changing their shape.
6. Thread new bellows around the axle.
Tape over the mating surfaces to keep grit from getting on them.
7. Mate surfaces and attach clips to the high points of the bellows- if you pre-bent the clips, they should hold the bellows together for assembly – they will be tightened later in the procedure.
Do not attach the clips to the ends of the bellows at this time.
To make it easier to hold the surfaces together, loop a piece of string around the bellows in the ‘valley’ adjacent to the clip you are attaching.
8. Slide small end of bellows over the axle tube. Attach clip on end of the bellows. To tension the clip, squeeze gently with long nose pliers until the edges are just touching, and use a flat punch on the ends of the clip to flatten so that the worm clamp can be installed. Thread the worm clamp around the axle tube and attach but do not tighten.
9. Repeat for the large end- this will require stretching the bellows and a little fussing.
Use the looped string trick to hold the ends together to install the clip.
10. Orient the bellows so that the seam is facing the back of the car.
11. Attach the remaining clips in the ‘valleys’ of the bellows and tighten all the clips and the two end clamps so that they are secure and won’t move. CAUTION- too much tension on the clips will cause the mating surfaces to go out of alignment.
12. Lower the car so that it is on its wheels and fill the differential with gear oil.
Access for filling while the car is on the ground is adequate with the fuel tank removed. Filling the differential with the wheels elevated will overfill the axles and likely cause a leak.
13. Reinstall the fuel tank. Open a beer.
