F10143 Force CHOKE SHAFT RETURN SPRING

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SAFETY REPLACE, INSPECT, AND/0R RETIGHTEN CRANKSHAFT COUNTERWEIGHT BOLTS 3508, 3512, 3516 ENGINES - MAILED US AND CAN ADA, CACO, COFA, BRAZIL, CFEL, COSA
  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.
REPLACE, INSPECT, AND/OR RETIGHTEN CRANKSHAFT COUNTERWEIGHT BOLTs, 3508, 3512, 3516 Engines, 1202 PI1007 U-55 A-49 AU-43 B-21 C-51 E-45 O-37 SAFETY Cross out your copy of the March 16, 1983 Service Letter PI3005, and add a note referring to this new Safety Service Letter. PI3005 is canceled. Problem There are now two potential problems with the crankshaft counterweight bolts on the above engines. First, as announced in the March 16, 1983 Service Letter, engines may have loose or improperly tightened bolts. Now, more recently we have discovered some of these bolts used in later engines and for parts service are too brittle and the heads can break off. Loose or broken bolts can cause the counterweight to interfere with the connecting rod. This interference usually breaks the remaining counterweight bolts. The loose counterweight will damage the engine and could be thrown through the side of the block. Bolts with good material are now used in production and are in the Parts Department. Part number did not change, but the good bolts can be easily identified from the potentially defective bolts by the arrangement of the letters on the heads. See Illustration. (SEE ILLUSTRATION) For a short time, bolts with known good material were used in production, but with markings the same as the bolts with potentially defective material. These bolts have a dot of red dye on the bolt head. Some engines have been reworked at the factory and are identified by the stamp "N-9" on the block near the serial number plate. A special lubricant instead of engine oil is still used on the bolts to prevent any damage to the mating parts when the bolts are tightened, and the tighter torque-turn method is used. Affected Engines, Parts Needed, Labor Allowances There are four areas of concern to be covered by this Safety PIP as a result of the two problems with the counterweight bolts. There are three groups of engines, A, B, and C, which need different work and quantities of parts. Parts stock inspection is designated as area (D). A) Later engines shipped with possibly defective bolts. B) Earlier engines shipped with some possibly loose or improperly tightened bolts of good material, and not yet inspected or reworked with new bolts per March 16, 1983 Service Letter. C) Engines shipped with some possibly loose or improperly tightened bolts of good material (Group B), but already reworked with new, parts service bolts. These parts service bolts may have the defective metal. D) Possibly defective bolts in dealers' parts stocks. The following Chart lists the three Groups A, B, and C of the affected engines and warranty labor hours. (SEE ILLUSTRATION) Action Requested (Parts Stock Action Needed) Do this work immediately, giving priority to users' engines. ****Group (A) - Engines Shipped With Possible Defective Bolts**** 1. Remove side covers as needed to reach the counterweight bolts. Some other attachments and parts may have to be removed before the side covers are taken off. 2. Use 9S9082 Engine Turning Pinion to turn crankshaft as needed. 3. Remove only one bolt from the counterweight. 4. Using a new bolt, put Fel-Pro C100 compound on the new bolt threads, shank, and under the head to prevent damage when it is tightened. : No other thread lubricant is acceptable at this time. Please note this in all the 3508, 3512, and 3516 Service Manuals. Corrections have been or will be made regarding the article in the February 28, 1983 Service Magazine and April 27 Engine News. If necessary, North American dealers can obtain the name of the nearest Fel-Pro dealer from the following (other dealers see attached list of locations): FEL-PRO Inc. 7450 N. McCormick Blvd. Box C 1103 Skokie, IL 60076 U.S.A. Telephone: 312-761-4500 312-674-7700 TELEX: 4330156/TWX 910-223-3603 Cable: FELPROINC, SKOKIE 5. Install the new bolt and tighten to 50 +/- 5 N X m (37 +/- 5 lb ft). Be sure satisfactory bolts are used - see head markings in Illustration. 6. Turn bolt an additional 1/3 turn (120 +/- 5 deg.). 7. Remove all the remaining bolts, one at a time, and replace with the new bolts. 8. Stamp "3F" on the block next to the engine serial number plate. ****Group (B) - Engines Shipped With Loose Or Improperly Tightened Bolts**** If the engine is at a job site, take a quantity of bolts in case some bolts have to be replaced. Do the following procedure, one bolt at a time: 1. Loosen the crankshaft counterweight bolt about one full turn, noting whether or not the bolt seems to turn without any unusual amount of effort. If the bolt backs out one full turn and appears to be free of any unusual amount of effort or resistance, simply tighten the same bolt back to a torque of 50 +/- 5 N X m (37 +/- 4 lb ft). Now, tighten the bolt an additional 1/3 turn (120 +/- 5 deg.). OR 1a. If a bolt seems to require too much effort when it is loosened one full turn, or if for some reason you feel "uncomfortable" with the "feel" of the bolt, remove the bolt. The bolt threads could be damaged. Do not use this bolt. 1b. Inspect the threads in the crankshaft and look for debris in