Camshaft: Service and Repair

Camshafts

Special tools, testers and auxiliary items required

• Puller (T40001)

• Retainer (3036)

• Sealant (D 154 103 A1)

Removing

• Sealing surfaces on the bottom of the guide frame and on the top of the cylinder head must not be worked.

• Camshaft bearings are integrated in the cylinder head and 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 the sealing 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, with Divided Toothed Belt Guard ] Toothed Belt, With Divided Toothed Belt Guard.

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

- Loosen the camshaft sprocket bolt and remove it approximately 10 mm (use the (3036) to counter hold it).





- Remove the camshaft sprocket using (T40001), (T40001/6) and (T40001/7). The (T40001) supports itself on the bolt - arrow -.





- Remove the camshaft sprocket bolt.

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

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

- Carefully remove the camshafts upward and place 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 rocker levers make contact correctly on the valve stem ends.

- Lubricate the journal surfaces of the camshafts.

- Carefully insert the camshafts into the camshaft bearings in the cylinder head. The cam lobes - A - of cylinder 4 must face toward one another.





- Apply an even, light bead of sealant (D 154 103 A1) in the clean groove of the guide frame.





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

• Placing the guide frame in place and tightening the bolts should occur without interruption, since the sealant begins to harden immediately when the sealing surfaces come into contact.

• Note the expiration date of the sealant.

- Place the guide frame on the cylinder head.

- Gently tighten the bolts working from the inside toward the outside in several stages.

- Then tighten the bolts in the designated sequence to 8 Nm + an additional 90° (1/4) turn.





- Install the sealing cap - item 25 -=> [ Sealing Cap ] Service and Repair approximately 1 to 2 mm deep using (3334).

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

- Install the rear toothed belt guard.

- Install the woodruff key into the camshaft.

- Install the camshaft sprocket. To tighten the bolt, hold the sprocket in place using (3036). Tightening specification, refer to => [ Valvetrain 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 woodruff key is properly seated.

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

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

=> [ Toothed Belt, without Divided Toothed Belt Guard ] Toothed Belt, Without 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 installation is basically a reverse of the removal sequence.