SUPPORT AS 4446557 - Caterpillar

Do not disconnect any oil lines until all oil pressure in the main system has been released.
1. Disconnect oil lines (1), (2) and (4).2. Remove four bolts (5) that hold summing valve (3) to the combiner valve. Remove the summing valve.Install Summing Valve
1. Put the summing valve in position as shown. Install the four bolts that hold the summing valve to the combiner valve.2. Connect the three oil lines to the summing valve.Disassemble Summing Valve
1. Remove four pistons (11) from the valve body.2. Remove seven O-ring seals (1) from valve body (2).3. Remove spring (3), valve (4), spring (5) and retainer (6) from valve body (7). Remove the shims from valve (4).4. Remove cap (9). Remove nut under the cap. Remove plunger (10) from cover (8).5. Inspect O-ring seals for damage and make a replacement of seals if necessary.Assemble Summing Valve
1. Clean all parts of the valve and put clean hydraulic oil on all parts. Install four pistons (1). Install five O-ring seals (15). Install O-ring seals (2) and (3).2. Install shims (6), spring (4) and spring (7) in valve (5). Install valve (5) and retainer (8) in the valve body.3. Install plunger (10) in cover (11).4. Install O-ring seal (9) in cover (11). Put the cover in position on the valve body and install four bolts (12).5. Make an adjustment to the plunger until it makes contact with the retainer. Install O-ring seal (13) and nut (14). Tighten the nut by hand only. Install O-ring seal (16). Install cap (17) and tighten by hand only.end by:a) install the summing valveb) adjustment of summing valve (See ADJUSTMENT OF SUMMING VALVE in TESTING AND ADJUSTING