1996/12/23 Caterpillar

Improved Relief Valve Group For Drive System Reduces Pressure Spikes{5069}

Usage:

143H (1AL),
163H (5AK) Motor Graders

Description of Change: The pressure setting was changed for the relief valve group in the control valve group for the drive system in the all wheel drive motor graders. The pressure setting was reduced from 38000 kPa (5500 psi) to 35900 kPa (5200 psi). The lower setting reduces pressure spikes (relief valve over-shoot). Pressure spikes can cause component failure.

Adaptable To: The improved 6E-3912 Relief Valve Group, identified by A6A125Z-40-359-N (stamped on the relief valve body), has the reduced pressure setting. The former 6E-3912 Relief Valve Group, identified by A6A125Z-10-5500-N (stamped on the relief valve body), has the higher pressure setting.

The improved (A6A125Z-40-359-N) 6E-3912 Relief Valve Group is effective with 143H (1AL156) and 163H (5AK74) Motor Graders. Earlier machines are adaptable.

NOTE: The former 6E-3912 Relief Valve Group (A6A125Z-10-5500-N) can not be adjusted to the lower 35900 kPa (5200 psi) pressure setting on machines in the field. A special test bench procedure is required for this adjustment.

6E-3906 Control Valve Group (1) 6E-3912 Relief Valve Group.

Caterpillar Information System:

1996/12/16 Tools Used For Transmission Overhaul {3400}

1996/12/16 1U-9069 Limp Home Switch Allows Transmission Control Valve To Be Remotely Operated If Controller Fails {3418}

1996/12/16 Use 1U-9079 PTO Alignment Tool To Aid In Aligning PTO Drive Shaft During Installation {3107}

1996/12/16 Tools Used For Removal And Installation Of Rear Axle Group {3278}

1996/12/16 Use 1U-9100 Adapter Cable To Connect Mid-Size Challenger's On-Board Electronic System To A Personal Computer {7490}

1996/12/16 O-Ring Available For 816328 E.H.P. Block {5125,5126,5059,5461,5466,6406,6460}

1996/12/16 Improved Fuel Sender Assembly Available {7481}

1996/12/16 Exhaust Outlet Tubes Used On Exhaust Heated Truck Body Groups To Keep Exhaust Soot And Condensation Off Rear Lamps {7258}

1996/12/16 Correct Ride Height Settings And Adjusting Procedure Must Be Used {7201,7213}

1996/12/16 New Steering Metering Pump Group Gives Smoother Steering Operation {4312}

1996/12/16 Alternative Brake Caliper Seal Kits Can Withstand Extreme Operating Temperatures {4256}

1996/12/16 Clamp Relocation In The Steer Lines Group Improves Service Life Of The 122-2229 Tube Assembly {4304}

1996/12/23 Externally Adjusted Relief Valve Used In Steering Control Valve Group{4307,4322}

1996/12/23 Orificed Check Valve Removed From Hoist Cylinder Groups For Truck Bed{5102,5486}

1996/12/23 Improved Seals And Bearings Used To Reduce Seal Leaks In Transfer Gear Groups (6WD){3250}

1996/12/23 Torque/Turn Method Used To Tighten Brake Caliper Retaining Bolts{4256}

1996/12/23 New Temperature Sensors Used Which Prevent False Over Temperature Warnings{1906,1400}

1996/12/23 New Telehandler Brake Pack Adjustment Procedure For Rebuilt Brake Groups{4251,4004,4255,4261}

1996/12/23 New Rotocoil Assembly Used In Engine Cylinder Head Groups{1109}

1996/12/30 Description Of August 1996 (AUG96) Personality Module Changes For 3176B (43Z), 3176C (7ZR), And 3196 (6AR) Engines {1902,1901,1923,7414}

1996/12/30 3054 Engine - New Rear Crankshaft Oil Seal Housing Provides Better Seal {1161}

1996/12/30 Seal Improvement Prevents Leakage In Hook Winch Groups {5417}

1996/12/30 Improved Seals And Bearings Used To Reduce Seal Leaks In Output Transfer Gear Groups {3159,3003}

1996/12/30 New Hydraulic Pump Group Increases Service Life {5070}