Rear Crankshaft Main Bearing Seal: Service and Repair
Removing And Installing Crankshaft Sealing Ring - Flywheel Side
CAUTION: When working on the engine, absolute cleanliness is essential. Even the smallest particles of dirt can damage engine components.
Preliminary work:
NOTE:
- On vehicles with Tiptronic transmission, disconnect the battery, as the starter must be removed to separate the torque converter from the drive plate.
- Note the work instructions for disconnecting and reconnecting the battery.
- Disconnect the battery.
- Remove Tiptronic transmission.
- Remove manual transmission.
- With the engine transmission unit removed, uncouple the transmission.
Tools
Item A - E:
Removing The Crankshaft Sealing Ring
NOTE: In order to avoid deforming the thrust plate housing, always loosen screws in several stages and in diametrically opposite sequence.
1. Remove the clutch pressure plate including clutch drive plate. Unscrew 6 M8 x 16 pan-head screws crossways in several stages. Remove the thrust plate, including the drive plate.
NOTE: Make sure not to damage the crankshaft flange when installing and removing the double-mass flywheel (DMF) or Tiptronic drive plate.
2. Remove the double-mass flywheel (manual transmission) or the drive plate for the torque converter (Tiptronic). Unscrew 8 M10 x 1 x 50 pan-head screws for the DMF or M10 x 1 x 25 in the case of the drive plate, remove DMF or drive plate. To counter, fasten toothed segment No. 9538/1 to the crankcase using an M12 x 50 hexagon-head bolt (fine thread) -figure-.
NOTE: Never use an abrasive or polishing cloth or brushes with metal bristles on the sealing surface of the crankshaft flange.
3. Carefully remove small edges or burrs on the chamfer of the crankshaft flange with an oilstone. Then, carefully degrease the crankshaft journal and crankcase bore (e.g. using a clean, lint-free cloth that has been soaked in solvent naphtha or acetone). Blow dry using a low air pressure (≤ 0.5 bar) or ventilate.
NOTE:
- The serial spindle sealing ring is pressed 11 mm in, measured from the end of the flange. The new sealing ring is pressed 13 mm in using the special tool insertion tool No. 9699 in order to generate a new running track.
- If the crankshaft flange is corroded, clean it as follows:
- Press the old crankshaft sealing ring in further with the special tool insertion tool No. 9699 in the same way as you would install a new sealing ring.
- Clean the crankshaft flange with a special metal-polishing pad (e.g. "Never Dull", available in car and motor bike accessory stores). Then, carefully degrease the flange (e.g. using a clean, lint-free cloth that has been soaked in solvent naphtha or acetone).
- Replace the crankshaft sealing ring as described below.
4. Spot drill the crankshaft sealing ring on the front -arrow- with a 3 mm drill bit, grease the drill bit beforehand.
5. Screw sheetmetal screw (5 x 20) with washer approx. 5 mm into the bore.
6. Pull out the sealing ring with the puller No. 9237 -arrow-. If necessary, clean crankshaft flange again.
Installing The Crankshaft Sealing Ring
NOTE:
- The tools should be thoroughly examined for any burred spots each time a sealing ring is fitted. Even minor damage to the tool can damage the micro sealing lips of the new sealing ring.
- The illustrations of the special tools show their use with the engine removed and on the assembly support. Their use with the engine installed is identical.
1. Small burred spots or damaged areas on the tools can be eliminated with a nail file, then pull off with a fine abrasive or polishing cloth. Remove residual dirt on the tools, e.g. using solvent naphtha or acetone.
2. Check crankshaft installation position. To do this, insert special tool measuring mandrel No. 9699/1 across the crankshaft flange into the fitting bore of the crankcase -figure-. The measuring mandrel must be placed with slight resistance in the bore. If the measuring mandrel cannot be positioned, the engine must be replaced.
NOTE:
- The crankshaft sealing ring must not be oiled or greased. The micro sealing lips, in particular, are so sensitive that even the smallest contact can cause damage.
- Coat only the crankshaft case bore with new oil.
3. Coat the crankshaft case bore with new engine oil and slide the new crankshaft sealing ring over the crankshaft flange.
4. Fit insertion tool No. 9699 between the two internal M8 pan-head screws, (hexagon socket a/f 8) -with hexagon socket wrench insert- on the crankshaft flange and fasten it. The crankshaft flange's dowel pin must sit in the bore of the device.
5. To position the crankshaft sealing ring correctly on the crankshaft flange, turn an open-end/ring wrench in a clockwise direction as far as it will go on the hexagon (a/f 19) of the device -figure-. Then remove the tool by releasing the pan-head screws.
6. Install the DMF or drive plate. Make sure that the crankshaft flange is not damaged.
7. Install the clutch pressure plate and drive plate.
8. Refit or install the transmission.
9. Install the engine/transmission unit if necessary.
Checking piston wear
1. Clean the removed pistons with solvent naphtha. To identify the dimensional group (punched on the piston crown), carbon deposits must be carefully removed, e.g. with a brass brush.
2. Check the piston diameter -D- at the piston skirt using an external micrometer. The measurement -X- is made at 16 mm from the bottom edge of the skirt.
NOTE: The piston must be replaced if the wear limit is exceeded.
The maximum permissible wear at the specified measurement point is 100 mu.m (= 0.1 mm). The piston must be replaced if this dimension is exceeded. The reference dimensions for the piston groups are to be taken from the table.
NOTE:
- Original pistons from the Porsche spare parts catalogue are available in the dimension group "X" only.
- Note the different weight groups