TECHNICAL INFORMATION BULLETIN
May 25, 2005
IT62G (S/N: AKP1-Up; 6PS1-Up)
950G Series II (S/N: BAA1-Up; AYB1-Up; AYD1-Up; AYL1-Up; AXR1-Up; AYS1-Up; AXX1-Up)
950G (S/N: 2JS1-Up; 4BS1-Up; 6NS1-Up; 3JW1-Up; 5FW1-Up; 5MW1-Up; 8JW1-Up)
962G Series II (S/N: BTA1-Up; BAB1-Up; BAC1-Up; BAD1-Up; AYE1-Up; AYG1-Up; AXS1-Up; AXY1-Up)
962G (S/N: BDP1-Up; 3BS1-Up; 5AS1-Up; 5RS1-Up; 4PW1-Up; 6EW1-Up; 6HW1-Up; 7BW1-Up)
966G Series II (S/N: AXJ1-Up; AXL1-Up; ANT1-Up; AWY1-Up; ANZ1-Up; AWZ1-Up)
966G (S/N: AAH1-Up; 3ZS1-Up; 9RS1-Up; 3PW1-Up; 3SW1-Up; 8XW1-Up)
972G Series II (S/N: AXC1-Up; AXE1-Up; AXN1-Up; AWP1-Up; AXP1-Up; ANY1-Up)
972G (S/N: 7LS1-Up; AAW1-Up; 1EW1-Up; 4WW1-Up; 6AW1-Up; 9GW1-Up)
980G Series II (S/N: AXG1-Up; AWH1-Up; AYT1-Up)
980G (S/N: 9CM1-Up; 2KR1-Up; 2SR1-Up)
980H (S/N: JMS1-Up)
SMCS CODE: 4268, 4306, 5055, 5070
DPSID: 00001369, 00003235, 00003236
SUBJECT: PROCEDURE TO DETERMINE WHICH SEAL IS LEAKING ON STEERING PUMPS ON 950/962G/G Series II & 980G/G Series II/980H WHEEL LOADERS
Pump Groups: 950/962G/G Series II & IT62G/G Series II, 167-0994 Steering Pump, 980G/G Series II/980H, 105-3635 Steering Pump
This procedure is provided in order to allow technicians to properly diagnose the source of seal leak on the above listed Steering Pumps. Possible leak sources include the pilot flange O-ring, the inner shaft seal, or the outer shaft seal.
SOLUTION: If a leak is observed around the weep hole area of a Steering Pump, it could be caused by either of the following reasons. 1) A leaking O-ring around the pilot flange, or 2) A shaft seal leak, either inner or outer, that results in leakage at the weep hole. A leaking shaft seal, inner or outer, can be difficult to differentiate from the pilot flange O-ring leak because the weep hole locations are near the mounting flange and on the lower half of the pump, pointing down. Therefore, any oil that leaks around the pilot O-ring could run down to the weep hole and be mistakenly diagnosed as a shaft seal leak.
If a leak is suspected, it will be necessary to identify positively whether the leak source is at the 1) O-ring around the pilot flange, or 2) Shaft seal, inner or outer. If a leak is discovered, the recommended first course of action is to add blue color dye to the Transmission Oil, and red color dye to the Hydraulic Oil. Then, operate the machine for a reasonable amount of time, several Service Meter Hours (SMH?s), in order to allow both respective color dyed oils to adequately circulate to the Steering Pump, and to leak.
The next phase of diagnosis will be to remove the Steering Pump from the machine, and to inspect the leak to determine the source of leakage. Attempt to determine the precise source of the leak since there are three possible sources. First determine whether the leak is from the flange, or from the weep hole. It may be possible at this point to positively determine that the source of the leak is blue color dyed Transmission Oil that is leaking at the pilot flange.
However, if the leak is from the weep hole, there are two other possible sources. The presence of blue dye colored Transmission Oil in weep hole cavity indicates that Transmission Oil entered through the outer shaft seal. If instead red dye colored Hydraulic Oil is observed in weep hole cavity, then the source of the leak is Hydraulic Oil that has entered the cavity through the inner shaft seal.
In order to determine which shaft seal is leaking, the outside shaft seal must be removed. The presence of blue or red dye colored oil in the cavity between the shaft seals can then be confirmed. And if present, whether oil is blue dye colored Transmission Oil or red dye colored Hydraulic Oil. This procedure should be done as soon as possible after removing the pump from the machine. If the pump is allowed to set for many hours or days, there is a chance that the oil could run out of the weep hole or continue to leak out of the shaft seal cavity and cause difficulty in determining if one of the shaft seals was leaking.
PROCEDURE: The following procedure and pictures provide guidance in performing the diagnosis.
Observe the weep hole to determine if oil is present. There should be a porous bronze plug installed in the weep hole and it should be free from paint or dirt that would plug the hole and would seal oil inside.
- Observe the seal cavity of the weep hole and note if oil is present. If present, determine whether oil in the cavity is blue dye colored Transmission Oil, or red dye colored Hydraulic Oil.
- Generate a Service Information Management Systems (SIMS) ticket and specifically describe whether the inner or outer shaft seal, 8T-4750, was determinied to be the source of the leak.
Note: A thin film of oil is put on the seal during assembly of the pump, but the seal should then only appear as slightly wet with oil. In the picture, there was clearly oil "puddling" in the seal cavity confirming a shaft seal leak.
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