To install new spool seals when the centering spring (tilt spool) or other detent assembly (lift spool) are not removed from the spool, use the following procedure:
Check the seal surface area (in the control valve) for rust, corrosion, scratches, etc. Correct any irregularities before continuing.
Install the back-up washer on the spool.
Put plastic material on the valve spool [Figure 20-40-83].
Put clean oil on the spool seal. Install the spool seal (Item 1) [Figure 20-40-83] on the spool being careful not to damage the seal on the sharp edges.
Remove the plastic material and install the spool into the control valve.