Valve Spring: Service and Repair

Valve Stem Oil Seal and Valve Spring Replacement

Tools Required
^ J26999 Compression Gage
^ J26999-20 Compression Gage Adapter
^ J44646 Valve Spring Compressor
^ J44640 Valve Stem Seal Installer

Removal Procedure
1. Remove the engine cover.





2. Remove the upper and lower fan shroud.
3. Remove the valve rocker arm shaft, valve bridges, and pushrods for the cylinder head being serviced.
4. Remove the glow plug for the cylinder requiring service.
5. In order to apply shop air to the cylinders use the following procedures to modify J26999-20 (1) and J26999 (2):
1. Remove the valve core from J26999-20 to allow air to flow.
2. Remove the quick connect fitting from J26999.
3. Adapt the quick connect fitting in order to use for shop air.
4. Connect the quick connect fitting to J26999-20.

Important: Rotate the cylinder to be serviced to the bottom of the stroke. This is to ensure that the engine does not rotate when the compressed air is applied to the cylinder being serviced.

6. Install J26999-20 into the glow plug hole for the cylinder being serviced.
7. Apply compressed air to hold the valves in place. If the compressed air is released, the valves can drop into the cylinder.





Caution: Compressed valve springs have high tension against the valve spring compressor. Valve springs that are not properly compressed by or released from the valve spring compressor can be ejected from the valve spring compressor with intense force. Use care when compressing or releasing the valve spring with the valve spring compressor and when removing or installing the valve stem keys. Failing to use care may cause personal injury.

8. Install J44646 to the rocker arm bosses on the cylinder head. J44646 should be installed in the rocker arm boss next to the cylinder being serviced. The pivot pin can be removed from the stand to allow the stand to be installed. The lever has different locating holes for the pivot pin depending on available clearance. The lever is also notched for different locations of the compressor.
9. Using J44646 compress the valve spring.





10. Remove the valve keys (1) from the valve stem.
11. Carefully release the valve spring tension.
12. Remove the valve spring upper seat (2) and the valve spring (3).
13. Remove the valve stem oil seal (4).
14. Remove the valve spring lower seat (5).
15. Continue removing the remaining valve stem seals for the cylinder using the above procedure.

Installation Procedure





Notice: Air pressure should remain applied to the cylinder for installation.

1. Install the valve spring lower seat.
2. Install the valve stem seal using J44640.





3. Install the valve spring (3), the painted end of the valve spring goes toward the cylinder head.
4. Install the valve spring upper seat (2).





Caution: Compressed valve springs have high tension against the valve spring compressor. Valve springs that are not properly compressed by or released from the valve spring compressor can be ejected from the valve spring compressor with intense force. Use care when compressing or releasing the valve spring with the valve spring compressor and when removing or installing the valve stem keys. Failing to use care may cause personal injury.

5. Using J44646 compress the valve spring.
6. Install the valve keys to the valve stem.

Notice: The valve stem keys must correctly seat in the valve spring cap. Engine damage may occur by not installing properly.

7. Carefully release the valve spring pressure. Make sure the valve keys stay in place.
8. Continue to install the 3 remaining valve stem seals for the cylinder.





9. Release the compressed air holding the valves in place.
10. Remove J26999-20 (1) from the glow plug hole.
11. Continue to replace the valve stem seals on the remaining cylinders using the above procedures.
12. Install the glow plug.
13. Install the valve rocker arm shaft, the valve bridges, and the push rods.
14. Install the upper and lower fan shroud.
15. Install the engine cover.