Gearbox seals??

[Greasyone]

Hi everyone! I'm new to this forum. I've owned and maintained several Mercedes including a 1960 220SEb W111 assembled in Australia.

I have the manual transmission/gearbox out to inspect and replace leaking seals.

How do you insert this type of seal without damage?? Picture attached.

Thanks!

[Benz Dr.]

You need a special installing tool or you will never get it to install correctly. I made my own on a lathe. I'll measure mine and post the sizes later this week.

[ja17]

In my case I found a hole-saw, just the right size.  I ground the teeth off the hole saw so it was flat, then used it to drive the seal in place. Worked just fine.

[Greasyone]

Hole-saw is a good idea. Will investigate.

The small one is for the speedometer drive. The old one did not want to come out easily! Even with heat, we had to use far more pressure to drive it out than I was comfortable with! The thought of cracking the alloy cover....

[Greasyone]

Found this very informative gearbox schematic on a Ponton website. It's a Daimler Benz training aid. Someone spent many hours putting it together!

[Greasyone]

Following up on your suggestions, my son showed the seal to a machinist at his work who effortlessly made up a brass tool which worked well to drive it in.

For future reference, the tool measures 34.8 mm OD, 32.8 mm ID and 22 mm deep.
Pictures attached.

[Benz Dr.]

I use a drill a bit smaller than the OD of the speedo seal. There is a void inside the casting with a shoulder in front of it so that the seal will only go into the casting up to the shoulder. After I drilled through the old seal I found that I could easily pick out what was left of the outer shell of the old seal.  The void in the casting is designed so that the shaft that drives the speedometer will expand the seal slightly as it slides through the seal when it's installed. This void is needed so that the seal can expand and stay tight against the shaft.