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Engine guides and mods

MHD Belt Change

Modification Details

Jack the car up and remove the wheel to access the belt cover.
Each end of the belt cover is a plastic plug.

They are nice and easy to lever out...

...which releases the clips on the other side.

With both plugs pulled down, the cover can be pulled from the car.

You'll now be able to see the terrible belt setup of the MHD. Take a 24mm spanner, place it over the
base of the belt tensioner. Push the spanner down to hold the tension and loosen the central Torx E bolt.
Carefully lift the 24mm spanner to release the tension on the belt.

Look to the back and you'll see a black pulley wheel. This is the water pump pulley.
You'll need to remove the 4 bolts to remove the pulley. They can be Torx E bolts...

...or regular hexagon headed bolts.

The belt can now be slipped off and a new one fitted. Refit the pulley and grab your 24mm spanner.
Put it back on the belt tensioner and push the spanner down as far as it will go.
Tighten the Torx E bolt in the centre of the belt tensioner and you are done.


Just cut the old belt off. Be very careful though, there is a shit load of tension in that belt.

Part Number

The smart part number for this belt is A0029931396. (as printed on the belt in the previous photos).
They can be bought from a smart or Mercedes dealer. No one will sell them cheaper than a dealer.


Thanks to Per E for testing out and confirming the guide that I gave him. Also for the last photo.

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