PSP FOR 231D HYDRAULIC NOISE AND AERATION - COSA LETTER NO. 1 - MAILED COSA Caterpillar

January 11, 1993
COSA LETTER No. 1
PRODUCT SUPPORT PROGRAM FOR 231D HYDRAULIC NOISE AND AERATION
5458  PS4891
NOTE: This Program can be administered either before or
after a failure or complaint. In either case the
decision whether to apply the Program is made by the
dealer. When reporting the repair, use "PS4891" as
the Part Number, and "7755" as the Group Number. If
administered before failure, use "56", and after
failure "96" as the Warranty Claim Description Code.

January 31, 1994

The location of the hydraulic oil return baffle tube inside the
231D hydraulic tank causes oil aeration when the machine is used
in slope operation. Oil aeration results in noise from the
hydraulic pumps and cause air to get trapped in the pilot
controls and implement cylinders.
The 6E2849 Valve in the oilcooler by-pass valve group is unstable
and vibrates causing irritating noise at certain engine speeds.
The noise level will increase when the hydraulic oil is aerated.
HEBE1409

Model Identification Number
*** Group 1 ***
231D  5WJ1-72, 76-82, 86-108, 112-116, 119-197,
199-243, 245, 247-260, 262, 266-284,
292-304, 315
*** Group 2 ***
231D  5WJ73-75, 83-85, 109-111, 117-118, 198, 244, 246,
261, 263-265, 285-291, 305-314, 316-330

1 - 105-3663 Tube As-Baffle
1 - 105-3784 Valve

*** Group 1 ***
Drain approx. 100 liters of oil from the hydraulic tank into a
clean container. The oil should be re-used. If the rework can be
scheduled to coincide with the regular oil change it is not
necessary to salvage the oil. Remove the 8J3803 Coupling and
8J3702 Head assembly (tank cover). Replace the 9J3537 Tube
As-Baffle inside the tank by the new 105-3663 Tube As-Baffle.
Install the 8J3702 Head assembly and 8J3803 Coupling.
Remove the 6E0605 Plug from the 6E2842 Valve group - oilcooler
by-pass valve. Replace the former 6E2849 Valve by the new
105-3784 Valve. Install the 6E0605 Plug. Fill the hydraulic tank
to the proper level. Start the engine and check for leaks.
*** Group 2 ***
Replace the 9J3537 Tube As-Baffle as described. The 105-3784
Valve has been installed at the factory on the machines in this
serial number range.

Product AVSpare Dealer Suggested Customer Suggested
smu/age Parts Labor Hrs Parts Labor Hrs Parts Labor Hrs
whichever (D/N) (Cost)  (C/L) (Sell)
comes
first
*** Group 1 ***
0-2000 100 % 3.0 0 0  0  0
0-24 mo.
2001-3000 33 1/3% 1.5 0 0 50 % 1.5
25-36 mo.
*** Group 2 ***
0-2000 100 % 2.0 0 0  0  0
0-24 mo.
2001-3000 33 1/3% 1.0 0 0 50 % 1
25-36 mo.

Handle the parts in accordance with your Warranty Bulletin on
warranty parts handling.