1. Clamp chain tensioner in a vise and remove upper circlip.
Spring retainer under pressure.
2. Remove spring retainer and spring.
3. Remove bleed screw and sealing ring.
4. Pull out aluminum piston carefully with a suitable tool.
1. Clean parts thoroughly, check for wear and replace if necessary.
Inspect piston spring for wear and deformation (bent) , replacing if necessary.
Push chain tensioner piston with mounted aluminum piston, without O-rings, into chain tensioner housing. Both pistons must move easily. It is especially important that the chain tensioner piston moves easily in the lower piston position. Remove any pressure spots on the pistons with emery cloth.
3. Install spring guide, spring. cage, spring, ball, intermediate piece with O-ring as well as piston and secure with snap ring.
5, Push lower snap ring out of groove with a small screwdriver inserted through bleed screw bore.
6. Remove piston, intermediate piece with O-ring valve ball (5 mm) with spring, cage for ball, spring and spring guide.
The intermediate piece could be stuck in the piston. If so, remove intermediate piece by lightly tapping piston against piece of wood.
When installing intermediate piece in the piston make sure O-ring fits properly in groove. Give O-ring a light coat of oil.
4. Fill chain tensioner to upper edge with 1 5 W/50 engine oil and bleed.
Bend the end of an approx. 1 mm dia. steel wire to make an inclined step and push it through the piston bore against the ball (see Workshop Manual 911, Volume 1, Page E 106).
Move piston up and down slowly within the stroke range until no more air bubbles escape at the bores.
5. Clean inner and outer grooves of aluminum piston. Install new, lubricated O-rings and make sure they are not twisted. Install aluminum piston until the O-ring seals with the housing, Now open the bleed screw slightly and push down with Special Tool P 214 c until the tool rests on the edge of the chain tensioner. Then tighten bleed screw again without delay,
Install spring, spring retainer and snap ring.
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