SWITCH AS-TEMPERATURE 8T9793 - Caterpillar

Procedure To Evaluate Filter Bypass Valve
1. Remove the bypass spool and spring from the filter base.2. Insert the spool all of the way into the spool bore in the filter base.3. Measure distance (A) from the shoulder of the spool to the spotface on the filter base. See Illustration 1.
Illustration 1. Dimension (A).4. Remove the spool from the base and measure the shoulder length of the spool, dimension (C). See Illustration 2.
Illustration 2. Dimension (C).5. Add dimensions (A) and (C). If the sum is less than 96.0 mm (3.78"), the valve might not open fully due to housing dimensions. The housing can be reworked to current specifications. See the procedure on how to rework 9P0113 Filter Base. Housings with annulus (E) are older, and are more likely to need rework because spool travel was limited by a cast surface rather than by a machined surface.
Illustration 3. Dimension (B) and location of annulus (E).6. If the shoulder length of the spool, dimension (C), exceeds 54.69 mm (2.153") that can also limit opening of the bypass valve. The spool can be reworked to current specifications. See the procedure on how to rework 9P1508 Bypass Spool.Procedure To Rework 9P0113 Filter Base
1. Obtain a 22.225 mm (.8750") diameter four-fluted, flat-bottomed, end-cutting core drill. A sharp shoulder radius on the core drill is preferred, but a chamfer or radius up to 0.76 mm (.030") is allowable. The core drill must be long enough to reach the bottom of the spool bore in the filter base.2. Taking care to avoid damage to the original spool bore, use the core drill to increase the depth of the spool bore in the filter base. The new depth, dimension (B), should be 96.5 0.5 mm (3.80 .02"). See Illustration 3.3. Remove any burrs and thoroughly clean the filter base.Procedure To Rework 9P1508 Bypass Spool
1. Grind the large end of the spool to produce dimension (D) on Illustration 4 of 74.00 0.25 mm (2.913 .010").
Illustration 4. Dimension (D).2. Grind external and internal chamfers on the spool as indicated.3. Remove any burrs and thoroughly clean the spool.