CAP ASSEM. 7M7856 - Caterpillar

Introduction
This measuring tool group is a combined set of tools for measuring the limit of separation (liftoff dimension) on Rexroth A6 Motors and A7/A8 Pumps. This kit contains all the necessary tools to measure five pump/motor sizes (55, 80, 107, 160, and 200 cc). Each gauge plate is laser engraved with the part number for easy identification. Over 600 disposable gauge balls provide the capability to measure 200 or more pumps before reordering. One, 3/22 inch punch is provided to remove the gauge balls after measurements are taken. 1) Each gauge ball can only be used once. 2) Gauge balls contain lead and must be sent to a certified recycler for disposal. 3) A second set of 107cc and 160cc Gauge Plates are included to expand this kit for use on A8 Pumps.
Illustration 1. 149-4935 Pump and Motor Measuring Group. Refer to Chart A for item identification.Procedure
Prior to beginning liftoff dimension measurements, be sure the drive group is completely installed and the bearing pre-load is set. The following steps will establish the correct thickness of shim to maintain the correct liftoff limitation. Read and understand all instructions prior to beginning work. In the case of future changes or upgrades, these instructions are for reference purposes only, and the mechanic should follow their specific Disassembly and Assembly Manual Instructions.Pumps and Motors with Type 1 Barrel
Illustration 2. Type 1 Barrel Assembly.1. Remove all retaining plate screws, retaining plate, and pistons.2. Reinstall center pin (2), spring (1), retaining plate (3), and three screws (4) as shown in Illustration 3.
Illustration 3. (1)Spring(2) Center Pin.(3) Retaining Plate.(4) Screws.3. Select the correct gauge plate (for pump/motor size to be rebuilt) from the tool group, refer to Charts A or B.4. Place three 149-5141 Gauge Balls in the "TOP" of the gauge plate (one in each of the three outer holes) as shown in Illustration 4.
Illustration 4. Place Gauge Balls In Holes Indicated By Arrow. Gauge plates have the part number and the word "TOP" engraved on the upper side.5. To keep the gauge balls from falling out of the gauge plate during installation, press on each one with your thumb or place a small amount of grease in the three tapered holes. Pressing the balls too deeply into the gauge will provide inaccurate measurements.6. Install the gauge plate assembly into the cylinder barrel with the gauge balls facing away from center pin as shown on Illustration 5. Use a small amount of grease to hold the plate assembly in the cylinder barrel.
Illustration 5. Install Gauge Plate Assembly.7. Install the cylinder barrel onto the center pin as shown in Illustration 6.
Illustration 6. Install Cylinder Barrel Onto Center Pin. Do not drop the cylinder barrel onto center pin. this will prematurely crush the gauge balls, causing inaccurate measurements.8. Place valve plate and head group (5) on the drive motor; start all bolts (6) as shown in Illustration 7.
Illustration 7. (5) Valve Plate And Head Group.(6) Bolts.9. Tighten head bolts to the specified torque while turning pump/motor