E 420 (210.072) V8-4.2L (119.985) (1997)
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Valve Spring: Service and Repair
Preparation
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Camshaft removed. See: Camshaft, Lifters and Push Rods/Camshaft/Service and Repair
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Spark lugs removed.
Overview
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Lift up timing chain and rotate piston of cylinder to be machined to TDC with wrench bit, see table for piston in TDC.
Marking Number For Piston In TDC
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Crankshaft marking Number: 0
Pistons In TDC: 1 and 6
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Crankshaft marking Number: 90
Pistons In TDC: 5 and 3
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Crankshaft marking Number: 180
Pistons In TDC: 4 and 7
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Crankshaft marking Number: 270
Pistons In TDC: 8 and 2
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Remove bucket tappet (3) of the relevant cylinder, install.
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Screw connection hose (4) of cylinder leak tester into spark plug hole.
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Fix crankshaft in position with retaining lock to prevent it rotating. See: Service and Repair/Procedures
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Pressurize compression chamber.
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Insert hinged clevis (7a) into appropriate hole of the camshaft bearing cap in cylinder head.
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Attach lever depresser (9) with thrust piece (5) to hinged clevis (7a) special tools 111 589 18 61 00, 119 589 10 63 00 and 119 589 06 63 00, in
the appropriate hole .
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Position thrust piece (5) vertically onto valve spring retainer (15).
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Compress valve spring (17).
CAUTION: The valves must not strike the piston crown otherwise they Will be bent.
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Remove/install valve collets (14), with tweezers, special tool 116 589 06 63 00 (6), magnetic finger
Installation Note: Coat valve spring retainer (15) with grease for fixing the collets (14) in position.
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Remove valve spring retainer (15) together with valve spring (17), install.
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Replace valve stem seal (19). See: Seals and Gaskets/Valve Guide Seal/Service and Repair
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Remove bottom valve spring retainer (20) and examine for scoring, install.
Special tools
Commercially available tools
Cylinder leak tester e.g. Bosch E FAW210A Sun, CLT 228
Rubber suction cup 0 30 mm e. g. Hazat Nr. 735-2
Straight tweezers 160 mm with 9. g. Stahlwille rounded tips D-42331 Wuppertal 12
