Removing Valve-Stem Seal

Information 

When required, all valve-stem seals on both cylinder rows must be replaced.

Information 

• Before switching to another cylinder, the cylinder must be positioned at the bottom dead center and supplied with compressed air. 

Information 

• Position the pistons of the relevant cylinder at the bottom dead center. 
• Each piston is pressed downwards as pressure builds up in the cylinder. 

1. Set piston for the corresponding cylinder to bottom dead center. To do this, guide the timing chain carefully when turning the crankshaft.
2. Screw compressed-air hose from the tool set valve key assembly/disassembly tool for the Cayenne NR.54-1  (or similar) into the relevant spark plug bore so that it is tightly sealed. Ensure a constant compressed air supply to the cylinder (at least 6 bar overpressure). This builds up pressure in the cylinder so that the valve does not fall into the cylinder while you are working.  Replace all four valve-stem seals for a cylinder and refit valve keys. Only then fit compressed-air hose on the next cylinder and apply compressed air constantly.
3. Fit the tool on the cylinder head and adjust it.
   1. 3.1. Screw holder -1-  with the appropriate thread into its matching thread on the cylinder head. The hook piece -2-  is pre-fitted in the holder.
      Fig 1: Fitting Hook

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   2. 3.2. Insert a suitable plastic guide -1-  instead of the tappet.
      Fig 2: Inserting Plastic Guide

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   3. 3.3. Insert assembly cartridge -1-  for the valve keys into the plastic guide.
      Fig 3: Inserting Assembly Cartridge

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   4. 3.4. Hook the lever (assembly bar) -1-  into the hook and place correctly onto the assembly cartridge. Make sure that the tool and equipment can be used without tilting.
      Fig 4: Hooking Assembly Bar Into Hook Tool Fitted Correctly

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4. Remove valve keys.
   1. 4.1. Press assembly cartridge with the lever (assembly bar) against the force of the valve spring and keep it pressed → Pressing down tool  . The knurled screw of the assembly cartridge pushes forward -1-  .
      Fig 5: Pressing Down Tool

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      Fig 6: Pressing Down Lever And Knurled Screw

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      Information 

      The mechanic must practise for use of the assembly cartridge to be effective. Some repetitions must be made to ensure that the valve keys are correctly held in place.

   2. 4.2. Turn the knurled screw back and forth → Turning knurled screw back and forth  until the valve keys snap into place in the assembly cartridge -2-  and are held there. The knurled screw retracts.
      Fig 7: Turning Knurled Screw Back And Forth

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   3. 4.3. Remove assembly cartridge and check correct position of both valve keys -1-  .
      Fig 8: Removing Assembly Cartridge

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   4. 4.4. Pull out the knurled screw from the assembly cartridge -1-  and tap out the valve keys -2-  .
      Fig 9: Identifying Knurled Screw Assembly And Valve Keys

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5. Remove valve springs, concave washers and valve keys from the cylinder head.
6. Pull back sliding sleeve of puller 3364  . When positioning the puller 3364  on the fitted valve-stem seal, ensure that the metal edge of the valve-stem seal is positioned behind the corresponding metal edge of the puller. -1-  → Valve-stem seal in puller 
   Fig 10: Identifying Valve-Stem Seal In Front Of Puller

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   Fig 11: Identifying Valve-Stem Seal In Puller

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7. When engaging the puller 3364  , push sliding sleeve down and close the tool. -arrow- 
   Fig 12: Identifying Closed Puller

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8. Remove valve-stem seal by actuating the negative (sliding) hammer -arrow-  . Repeat the procedure for valves on the pressurized cylinder (convert tool as required).
   Fig 13: Removing Valve-Stem Seal

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