March 31, 1989

Circular Letter
(C-7366)

Subject: Request for Comments:

Proposed Requirements for Use of Lubricated SAE Grade 5 Roller Bearing Cap Screws

TO THE MEMBERS AND PRIVATE CAR OWNERS ROLLER BEARING MANUFACTURERS AND RECONDITIONERS

File: GC-1463
TWBL-23A
(C-7366)

Gentlemen:

Pursuant to continuing efforts to improve the performance of roller bearings and related components, the Mechanical Division General Committee has approved, subject to review of comments herein requested, the following measures to increase assurance of a consistently adequate level of critical clamping force on roller bearing assemblies over the full range of service conditions and practices:

1) The standard for roller bearing cap screws be revised to require use of those meeting SAE Specification Grade 5 instead of Grade 2.

2) Effective June 1, 1989, all new roller bearings must exclusively have Grade 5 cap screws.

3) New Grade 5 cap screws may immediately be applied in complete wheel sets to new, remanufactured, and reconditioned roller bearings.

4) After January 1, 1990, Grade 5 cap screws must be used, i.e., application of SAE Grade 2 cap screws is no longer permissible.

5) Subsequent to the date (anticipated to be June 1, 1989) of an implementing circular letter, all orders placed must be for SAE Grade 5 cap screws.

6) Secondhand cap screws being applied in complete wheel sets may immediately be lubricated with either AAR M-942 Journal Roller Bearing Grease, AAR M-963 Journal Box Lubricating Oil (car oil), or equivalent
lubricant that does not promote flash rusting; and these cap screws must be so lubricated whenever applied after June 1, 1989.

Under the provisions of AAR Standard S-050, the comments of all effected or interested parties are herewith solicited. Responses should be submitted within 30 days of the date of this circular to the Secretary -- Mechanical Division, Association of American Railroads, 50 F Street, N.W., Washington, D.C. 20001. All recommendations advanced will be considered prior to activation of applicable directives and adoption of final modifications to the governing specifications.

Sincerely,

Leavitt A. Peterson