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250-Cl8 CEB-168250-C20/C20B CEB-1074250-B15G TP CEB-26250-B17/B17B TP CEB-1047OverhaulCOMMERCIAL ENGINE BULLETIN

Detroit Diesel AllisonIndianaDolis. ndiana 46206PAGE 1 OF November 15, 1976

COMPRESSOR, NO. 1 BALL BEARING--RELIEVED OUTER RACE

PLANNING INFORMATION:EFFECTIVITY: All Model 250 Series I and II Compressor Assem bliesprior to the following serial numbers:

MODEL

Cl8c20C20BB15GB17B17B

COMPRESSOR CORRESPONDINGSERIAL NO. ENGINE SERIALCAC 23695B CAE 803563 BCAC 39094 CAE 823412CAC 33482 CAE 830478All AllAll AllCAC 80193 CAE 880189

REASON: To increase the reverse load capacity and toimprove the lubrication and flushing action ofthe compressor front ball bearing.DESCRIPTION: The angular contact bearing in the No. 1 positionis changed from a relieved inner race to arelieved outer race. The relieved outer race(1) permits more o il to enter the bearing, (2)helps to prevent entrapment of debris in theouter race, and (3) provides a deeper reversethrust load ball track than the present relievedinner race bearing.

Revision No. 1May 19, 1978

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25O-Cl8 CEB-168250-C20/C20B CEB-1074250-B15G TP CEB-26250-B17/B17B TP CEB-1047Page 2COMMERCIAL ENGINE BULLETIN

-COMPRESSOR, NO. 1 BALL BEARING--RELIEVED OUTER RACE

INTERCHANGEABILITY:COMPLIANCE

APPROVAL:MANPOWER:

MATERIAL AVAILABILITY:NEW PART NO.6876600

TOOLING:WEIGHT AND BALANCE:REFERENCES:

Not affected.Recommended on a use stock basis,i. e., incorporate when the bearing failstopass overhaul inspection and thespare stock of superseded bearings isdepleted.FAA-DER Approved.No additiona l man-hours will be required tocomplete this bu lletin at time of overhaul.

NOMENCLATURE QTY.Bearing, Ball 1

None.Not affected.CW-888, (X-1366 and RFSE 250-72-11

Revision No. 1May 19, 1978Published November 15, l

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250-Cl8 CEB-168250-C20/C20B CEB-1074250-B15G TP CEB-26250-B17/B17B TP CEB-1047Page 3COMMERCIAL ENGINE BULLETIN

COMPRESSOR, NO. 1 BALL BEARING--RELIEVED OUTER RACE

ACCOMPLISHMENT INSTRUCTIONS:I. Replace P/N 6871053 or P/N 6859095 Compressor Front Ball Bearingwith P/N 6876600 Ball Bearing when (a) the existing bearing does notmeet overhaul limits and (b) the spare stock of superseded bearingsis depleted.

IL Record compliance with Cl8 CEB-168, C20/C20B CEB-1074,B15G TP CEB-26, or B17/B17B TP CEB-1047 in the CompressorAssem bly (blue pages) Modification Record, Part HI of the Engine LogBook.

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250-Cl8 CEB-168250-C20/C20B CEB-1074250-B15G TP CEB-26250-B17/B17B TP CEB-1047Page 4

COMMERCIAL ENGINE BULLETINCOMPRESSOR, NO. 1 BALL BEARING--RELIEVED OUTER RACE

MATERIAL WORMATION:New P/N Qty Nomenclature- Old P/N Qty Disposition6876600 1 Bearing, Ball 6871053 1 A

685&5

Stock Disposition Notes:A Scrap rejected bearings only.

S&vice ManagerGas Turbine EnginesMJK:aw

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