Camshaft: Service and Repair

Camshafts

Special tools, testers and auxiliary items required

• Puller (T40001)

• Retainer (3036)

• Sealant (D 154 103 A1)

Removing

• The sealing surfaces on the bottom of the guide frame and on the top of the cylinder head must not be reworked.

• The 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 bolts was loosened, the camshaft seal and the cap must be replaced.

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

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

• With a divided toothed belt guard, refer to => [ Toothed Belt, with a Divided Toothed Belt Guard ] Toothed Belt, with a Divided Toothed Belt Guard.

• Without a divided toothed belt guard, refer to => [ Toothed Belt, without a Divided Toothed Belt Guard ] Toothed Belt, without a Divided Toothed Belt Guard.

- Loosen the camshaft sprocket bolt approximately 10 mm (use the retainer (3036) ).






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






- Remove the bolt and camshaft sprocket.

- Remove the toothed belt guard bolts and guard from the rear of the cylinder head.

- Loosen the bolts for the guide frame evenly working 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 rocker arms make contact correctly on the valve stems.

- Lubricate the journal surfaces of the camshafts.

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






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






• The 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 outside in several stages.

- Then, tighten the bolts in sequence - 1 through 6 - to 8 Nm + 90° (1/4) additional turn.






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

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

- Install the rear toothed belt guard.

- Insert the woodruff key into the camshaft.

- Install the camshaft sprocket. Hold the camshaft sprocket using the retainer (3036) and tighten the bolt. Tightening specification, refer to => [ Valvetrain Overview ] Service and Repair.






• When rotating the camshaft, the pistons may not be at TDC for any cylinder. The valves/pistons may be damaged.

• Be sure the woodruff key is properly seated.

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

• With a divided toothed belt guard, refer to => [ Toothed Belt, with a Divided Toothed Belt Guard ] Toothed Belt, with a Divided Toothed Belt Guard.

• Without a divided toothed belt guard, refer to => [ Toothed Belt, without a Divided Toothed Belt Guard ] Toothed Belt, without a 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.

Further installation is in reverse order of removal.