Use Of "ARCTIC REGION" Suspension Cylinder Seals In Temperate Climate Applications Caterpillar

Problem:

The two piece pressure seals currently used in non-arctic application front and rear suspension cylinders of Off-Highway Trucks may not give acceptable service life.

Solution:

The Service Magazine references listed below give details of the use of U-cup pressure seals for use in cold climate applications. The seals listed however may be used in the non-arctic conditions (i.e., Caterpillar of Australia territories) and should give better service life than the two-piece design. The seals can be fitted as a direct replacement for the current seals.

Currently, all front and rear suspension cylinders for 784B, 785B, 789B and 793B trucks are being fitted in production with arctic seals, regardless of temperature application. The front suspension cylinders of all 768C, 769C, 771C, 772B, 773B, 775B, 776C and 777C will soon be fitted in production with the arctic seals. The rear cylinders of these models are still using the two-piece seals, but may change later in the year after the introduction of rod boots.

It should be noted that the arctic seals are less tolerant of dirt that may pass by the wiper seal. If arctic pressure seals are to be used, Caterpillar recommends that the metal case rod wipers detailed in the reference article be installed at the same time. It is also recommended that the rear cylinders on the 784A/B, 785A/B, 789A/B and 793 A/B be inverted and fitted with rod boots (soon to be released).

Reference: SEPD0131 - Service Magazine article dated 19 October 1992, page 8, "New Suspension Cylinder Rod Seals for Arctic Region Applications".

Reference: SEPD0176 - Service Magazine article dated 11 October 1993, pages 10-14, "Rear Suspension Groups Inverted for Improved Seal Life".

Reference: T.I.B. - Technical Information Bulletin dated 22 September 1993, Component Code: 7201, "Rear Suspension Cylinders may be Inverted to Increase Seal Life".

Reference: SEPD0195 - Service Magazine article dated 28 February 1994, pages 11-13, "Metal-Case Rod Wiper Used in Truck Suspension Groups for Better Retention of the Wiper Seal".

Reference: SEPD0198 - Service Magazine article dated 21 March 1994, pages 4-5, "New Suspension Cylinder Rod Seals for Arctic Applications".

CATERPILLAR OF AUSTRALIA LTD. COPYRIGHT 1994 CATERPILLAR ALL RIGHTS RESERVED