Series 638 – Section 1.20 Rear Main Seal (Flywheel Housing Installed)

Section 1.20
Rear Main Seal (Flywheel Housing Installed)

The Turbotronic 638 rear main seal prevents the leaking of lubricating oil from the engine. The seal pressed into the rear main bearing carrier assembly (see Figure "Location of Rear Main Seal" ).‪

1.Rear Main Bearing‪	5.Rear Oil Seal‪
2.Thrust Washer‪	6.Seal Ring‪
3.Rear Carrier Housing‪	7.Stud‪
4.Piston Jet Valve‪	8.Spring PIn‪

Figure 1. Location of Rear Main Seal

Section 1.20.1
Replacement of Rear Main Seal

To determine if replacement of the rear main seal carrier is necessary, perform the following procedure. See Figure "Flowchart for Replacement of Rear Main Seal" .‪

Figure 2. Flowchart for Replacement of Rear Main Seal

Section 1.20.2
Removal of Rear Main Seal

Remove the rear main seal as follows:‪

1. Remove flywheel. Refer to "1.16.2 Removal of the Flywheel" .

   NOTICE:
   To avoid spacer plate damage, use care when removing and handling the spacer plate.‪

2. Remove spacer plate.
3. Remove the rear main seal.

Section 1.20.2.1
Inspection of Rear Main Seal

Inspect the rear main seal as follows:‪

1. Visually check the spacer plate for nicks and burrs on the sealing surface.
   1. If the spacer plate has nicks or burrs, replace the component. Refer to "1.20.3 Installation of Rear Main Seal" .
   2. If the spacer plate has no nicks or burrs, proceed with step 2 of inspection.
2. Visually check the spacer plate inside thrust bearing wear surface for nicks or damage.
   1. If the spacer plate inside thrust bearing wear surface is nicked or is damaged, replace the component. Refer to "1.20.3 Installation of Rear Main Seal" .
   2. If the spacer plate inside thrust bearing wear surface has not been nicked or damaged, reuse the component. Refer to "1.20.3 Installation of Rear Main Seal" .

Section 1.20.3
Installation of Rear Main Seal

Install the rear main seal as follows:‪

1. Install new seal ring in recess of the spacer plate. See Figure "Main Carrier Assembly Parts Location" .
   

   1.Rear Main Bearing‪	5.Rear Oil Seal‪
   2.Thrust Washer‪	6.Seal Ring‪
   3.Rear Carrier Housing‪	7.Stud‪
   4.Piston Jet Valve‪	8.Spring PIn‪

   Figure 3. Main Carrier Assembly Parts Location

2. Install new rear main seal.
3. Position the thrust washer halves so that they are in place and not overlapping ends.
4. Lightly coat the outer circumference of the spacer plate with clean lubricating oil.
5. Place spacer plate over locating dowel.
6. Press the spacer plate firmly against the crankshaft.
7. Install Allen head retaining screw.
8. Install the flywheel. Refer to "1.16.3 Installation of Flywheel" .
9. Run the engine to verify repair.