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1.Remove upper toothed belt guard and cylinder head cover.
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2.Loosen lock nut of adjustment screw "A" and back out screw until respective rocker arm
lies against plunger spring of unit injector. 3.Remove rocker arm securing bolts 5 to 1 (from outwards to inwards) using special tool
Triple square (10) wrench (MB995227) and remove rocker arm shaft. 4.Pull connector off unit injector. 5.Loosen securing bolts "B" for unit injectors using special tool Triple square (6)
wrench (MB995228) and remove bolts. 6.Pull ball stud out of injector unit.
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7.Insert special tool Injector puller (MB995219) into bolt holes of unit injector. 8.Turn spindle gently against unit injector. Tighten lock nut hand tight. 9.Pull unit injector upwards out of cylinder head seat with cautious taps of special
tool Slide hammer (MB995218).
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Lever old O-rings very carefully off unit injector using a "soft" tool. Above all ensure
that burrs are not caused on the seating for the O-ring.
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1.Clean O-ring seating surfaces on unit injector very carefully.
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2.Slide special tool O-ring installer A (MB995220) onto limit stop on unit injector. 3.Slide upper, thicker O-ring carefully onto assembly sleeve and into seat on unit injector. 4.Remove special tool.
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1.Clean O-ring seating surfaces on unit injector very carefully.
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2.Slide special tool O-ring installer B (MB995221) onto limit stop on unit injector. 3.Slide upper, thicker O-ring carefully onto assembly sleeve and into seat on unit injector. 4.Remove special tool.
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1.
caution |
- Each time work is performed which requires adjustment
of the unit injector via adjustment screw, the adjustment screw in the rocker arm and also the unit
injector ball stud must be renewed. otherwise excessive wear of the components is the result.
- It is absolutely necessary to renew the securing bolts of the unit injector.
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Before installing unit injector, check that new seals are properly seated.
note |
- New unit injectors are supplied with O-rings.
- If old unit injector is reused, O-rings must be renewed.
- The seals must not be twisted.
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2.Oil the seals and stem of unit injector.
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3.Check seat of unit injector in cylinder head for soiling or foreign objects (metal
shavings/carbon deposits etc.) and clean with compressed air, if necessary.
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4.Insert unit injector into cylinder head with great care.
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5.Fit valve assembly device special tool Valve lever support (MB995213) with special tool
Valve lever base (MB995229) on retaining frame of cylinder head as shown.
caution |
If the unit injector is pulled down by the securing bolts, there
is a risk of the unit injector not being pulled correctly into its seat. This can result in
engine running problems and starting problems. For this reason the unit injector may only be
secured after it has been pushed in its seat.
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6.Fit the new securing bolts and carefully screw in by hand onto stop arrow without force.
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7.Now fit special tool Valve lever (MB995210) with special tool Valve lever holder (MB995230). 8.Carefully press unit injector in its seat using special tool Valve lever (MB995210)
and maintain this force. 9.Carefully screw in securing bolts of unit injector by hand and without force onto
stop using special tool Triple square (6) wrench (MB995228). 10.Tighten new securing bolts as follows: Stage 1 = 3 N·m Stage 2 = 1/4 turn (90°) further Stage 3 = 1/2 turn (180°) further
note |
Renew adjustment bolts "A" and ball pins of unit injector.
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11.Put rocker arm shaft in place and evenly tighten new securing bolts in the sequence 1
to 5 hand tight. 12.Then evenly tighten to 20 N·m and 90° (1/4 turn) further in the
same sequence.
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13.Fit the dial gauge onto the adjustment screw of the unit injector as shown. 14.Turn the crankshaft in engine direction of rotation until the roller of the rocker
arm is positioned on the peak of the drive cam. Roller side "arrow A" positioned at highest
point. Dial gauge "arrow B" positioned at lowest point. 15.Remove dial gauge. 16.Now turn adjustment screw into rocker arm until a firm resistance is felt (unit injector
positioned at stop).
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17.Turn adjustment screw 180° back off limit stop. 18.Hold adjustment screw in this position and tighten the lock nut to the specified torque
of 30 N·m. 19.Push on unit injector connector and install cylinder head cover and toothed belt guard.
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