825057004 Mercury O-RING

The information supplied in this service letter may not be valid after the termination date of this program. Do not perform the work outlined in this Service Letter after the termination date without first contacting your Caterpillar product analyst.
This Program can be administered either before or after a failure.In either case the decision whether to apply the Program is made by the dealer.When reporting the repair, use "PS8382" as the Part Number and "7755" as the Group Number.If administered before failure, use "56" as the Warranty Claim Description Code and use "T" as the SIMS Description Code.If administered after failure, use "96" as the Warranty Claim Description Code and use "Z" as the SIMS Description Code.
This Revised Service Letter replaces the July 22, 1995 Service Letter.Changes have been made to the Rework Procedure.
Termination Date
July 31, 1996Problem
In some fast cycle applications, high ambient temperatures may cause the hydraulic oil to overheat on certain 320 and 320L Excavators equipped with 3066 Engines.
Affected Product
Mode & Identification Number
320 (8LK1-1489, 2DL1-Up, 8HL1-220)
320L (9KK1-Up, 1KL1-487)
Parts Needed
1 - 7Y1960 Core As. - Oil1 - 1199957ROM - Control Kit1 - Door As. (fabricate per Illustrations 2, 3 and 4)1 - Bottom Guard (fabricate per Illustration 5)Action Required
See Rework Procedure.
Service Claim Allowances
This is a 6 hour job.
Parts Disposition
Handle the parts in accordance with your Warranty Bulletin on warranty parts handling.
Attach.(1-Rework Procedure)Rework Procedure
For confirmation of overheating, complete the checklist in Illustration 1.When hydraulic oil overheating is confirmed on machines operating in high ambient temperatures, make the following machine modifications:
1. Replace the standard 4I7502 Hydraulic Oil Cooler Core with a four row 7Y1960 Cooler Core on the following machines: 2. Rework the left hand rear engine door enclosure into a louvered door assembly by fabricating from the existing rear door assembly (See attached Illustration 2, 3 and 4, to rework door) on all of the listed Affected Product except those with high or semi-high ambient package.3. Replace perforated radiator bottom guard (6I5978) with a solid bottom guard fabricated from 6I5978.Make a solid bottom guard (see attached Illustration 5) on the following machines: 4. Replace ROM (See 'Instructions for Replacing 320 ROM') in the electronic controller using 1199957 ROM Control Kit on the following machines:
Illustration 1
Illustration 2
Illustration 3
Illustration 4
Illustration 5Rework Procedure For Exchanging The Controller ROM
Before touching the ROM or controller, the mechanic should touch a metal structure to get rid of any static electricity. Change the controller ROM indoors to prevent dust or moisture from entering the controller.
1. Turn the key switch and disconnect switch off.2. Remove the 40-pin and 24-pin connectors from the controller with 4.0 mm hex wrench.3. Remove the controller from the machine.4. Remove controller cover mounting bolts and carefully raise the cover. Short wires connect the cover and the controller body. Remove the cover gently to avoid damaging the inner wires. The cover cannot be fully raised. See Illustration 6.
Illustration 65. Remove the O-ring seal for the cover. Do not reuse the seal.6. Push ROM holders in direction F to remove them. See Illustration 7.
Illustration 77. Insert screwdriver under the ROM as shown in Illustration 8 and raise it slightly. Do the same for other end. Repeat this step and remove the ROM carefully so as not to break pins of the ROM.
Illustration 88. Before installing the new ROM, practice ROM insertion using the removed ROM. Before touching the new ROM, touch a metal piece such as the controller cover to remove any static electricity from your hands.
9. Install the new ROM in the controller. The ROM pins should be at a right angle to the ROM body for easy installation. If needed, bend the ROM pins as shown in Illustration 9.
Illustration 910. Install ROM holders over the new ROM. See Illustration 7.11. Install the new O-ring seal in the groove in the controller body. See Illustration 10.
Illustration 1012. Install the cover on the controller body and carefully align the cover, O-ring and controller body.13. Install cover mounting bolts using thread lock material. Tighten the bolts to a 6.8 N m (5 Ft-Lb).14. Confirm that the key and disconnect switches are off. Mount the controller on the machine. Connect the 40-pin and 24-pin connectors to the controller. Support the connectors by hand until the hex bolt is tight.
15. Turn both key and disconnect switches on. The controller LED should be green. If a red light is on, repeat ROM change procedure. If no lights are on, check the connectors (Step 14). 16. Write the rework date on label and apply the label to the controller. See Illustration 11.
Illustration 11