Service Repair Manual
312C and 312C L Excavator
Model: 312C EXCAVATOR FDS
Configuration: 312C & 312C L Excavators FDS00301-UP (MACHINE) POWERED BY 3064 Engine
Disassembly and Assembly
3064 and 3066 Engines for Caterpillar Built Machines
Media Number -SENR5553-10
Publication Date -01/05/2012
Date Updated -15/05/2012
Gear Group (Front) - Install - Idler Gear Only
SMCS - 1206-012
Tool Part Number Part Description Qty
Keep all parts clean from contaminants.
Contaminants may cause rapid wear and shortened component life.
1. Use Tool (A) to install a new bushing (4) (not shown), if the bushing was removed.
2. Install idler shaft (5) onto the cylinder block.
Note: When the idler shaft is installed, ensure that the oil hole of the shaft is up. If
necessary, cool the idler shaft to 0 °C (32 °F) before installation. The temperature of the
idler shaft is lowered in order to ease the installation of the idler shaft.
Note: Ensure that the marks on the timing gears are in alignment. Align the fuel injection
drive gear with the "33" mark with the "3" mark on idler gear. Make an alignment of the "2"
mark on the camshaft gear with the "22" mark on the idler gear. Align the "1" mark on the
crankshaft gear with the "11" mark on the idler gear. The No. 1 cylinder is at the top center
position when these marks are in alignment.
3. Install idler gear (3) onto the idler shaft.
4. Install thrust plate (2) onto the idler shaft.
5. Install the washer and idler gear bolt (1) onto thrust plate (2). Tighten idler gear bolt (1) to a
torque of 34 ± 5