Camshaft: Service and Repair

Camshafts

Special tools, testers and auxiliary items required

• Puller (T40001)

• Counter-holder tool (3036)

• Sealant (D 154 103 A1)

Removing

• The sealing surfaces on the guide frame (bottom) and on the cylinder head (top) must not be worked.

• Camshaft bearings are integrated in the cylinder head or in the guide frame. Before removing the guide frame, the tension on the toothed belt must be released.

• If the guide frame was loosened, the camshaft seal and cap must be replaced.

- Remove the camshaft adjuster. Refer to => [ Camshaft Adjuster ] Camshaft Adjuster.

- Remove the toothed belt, refer to one of the following:

• => [ Toothed Belt, without Divided Toothed Belt Guard ] Toothed Belt, without Divided Toothed Belt Guard.

• => [ Toothed Belt, with Divided Toothed Belt Guard ] Toothed Belt, with Divided Toothed Belt Guard.

- Loosen the camshaft gear. Use the (3036) to do so.





- Remove the camshaft gear using the (T40001), (T40001/6) and the (T40001/7).





- Remove the toothed belt guard bolts from the cylinder head.

- Loosen the guide frame bolts evenly from the outside toward the inside and remove the guide frame.

- Carefully remove the camshaft upward and place it on a clean surface.

- Remove the old sealant from the guide frame groove as well as from the sealing surfaces.





- Prevent dirt and adhesive residue from entering the cylinder head.

Installing

• Sealing surfaces must be completely free of oil and grease.

• The pistons must not be positioned at Top Dead Center (TDC).

• Make sure that all roller cam followers make contact correctly on the valve stem ends.

- Oil the journal surfaces of the camshafts.

- Carefully install the camshafts into the camshaft bearings of the cylinder head. Cam lobes - A - of cylinder 4 must face each other.





Recesses - arrows - must point to each other vertically.

- Apply an even, slightly raised bead of sealant (D 154 103 A1) into the clean grooves of the guide frame.





• Note the expiration date of the sealing compound.

• Sealant must not be applied too thick. Wipe off excess sealant if necessary using a lint free cloth.

• Installing and tightening the guide frame bolts should be performed without interruption because the sealant begins to harden immediately as soon as it contacts the sealing surfaces.

- Place the guide frame on the cylinder head.

- Tighten the new bolts from the inside working toward the outside in several stages.

- Tighten bolts in the sequence shown.





- Drive in the cap - item 25 - in the => [ Valvetrain Assembly Overview ] Service and Repair using the (3334) approximately 1 to 2 mm deep.

- Install the camshaft seal. Refer to => [ Exhaust Camshaft Seal ] Service and Repair.

- Install the rear toothed belt guard.

- Insert the fitted key into the camshaft.

- Install the camshaft gear. To tighten the bolt, hold the camshaft gear in place using the (3036). Tightening specification, refer to => [ Valvetrain Assembly Overview ] Service and Repair.





• When turning the camshaft, the pistons may not be at TDC for any cylinder. Valves/pistons may be damaged.

• Be sure the fitted key is properly seated.

- Install the toothed belt, refer to one of the following:

• => [ Toothed Belt, without Divided Toothed Belt Guard ] Toothed Belt, without Divided Toothed Belt Guard.

• => [ Toothed Belt, with Divided Toothed Belt Guard ] Toothed Belt, with Divided Toothed Belt Guard.

- Install the camshaft adjuster. Refer to => [ Camshaft Adjuster ] Camshaft Adjuster.

- Install the cylinder head cover. Refer to => [ Cylinder Head Cover ] Service and Repair.

The rest of the assembly is basically a reverse of the removal sequence.