Valve Spring Lock: Service and Repair

REMOVAL
1. Turn the crankshaft to bring the 0° mark in line with the timing mark (top dead center for No. 1 and No. 4 cylinders) and remove the camshafts (all valves are closed in this position). Place a cover over the timing-cover aperture to prevent collets or seals falling inside.





2. Using magnetic tool 83 91 401, or equivalent lift out the cam-followers.

NOTE: Place all valve parts in order in stand 83 93 787, or equivalent to ensure that they are refitted in their original positions.





3. Fit protective sleeves 8393746 over the valve springs to prevent the tappet guides from being scored. Note how the sleeves are fitted.





4. Unscrew the spark plug for the cylinder concerned and fit compressed-air adaptor 83 94173 in its place. Connect the air line to put the piston and valves under pressure.








5. Holding sleeve 83 94181 on the valve head and in line with the stem, tap the sleeve sharply with a hammer. This should free the collets, which should now follow the tool out.





6. Lift out the spring cap and valve spring.








7. Remove the valve seal using special pliers 83 94 157, or equivalent.





INSTALLATION
1. Remove the shank from tool 83 93 803, or equivalent and fit the valve seal in the tool, with the taper facing inwards (away from the valve head).





2. Fit the seal onto the valve stem, tapping it carefully into position by means of a plastic face mallet.





3. Fit the spring and spring cap.





4. Position the collets in the groove in the spring cap as shown.





5. Using tool 83 94 181 with sleeve 83 94 207, or equivalents carefully tap the collets home.





6. Remove the plastic sleeves and fit the cam followers.