Distributor - HT4100 Gear Replacement
NO.: 87-I-25DATE: Jan. '87
GROUP: 6A
SUBJECT: HT4100 DISTRIBUTOR GEAR REPLACEMENT
MODELS AFFECTED: ALL HT4100 ENGINES
Previous bulletins on this subject, such as T-86-79, have described detailed procedures for diagnosis and repair. Most important among these procedures is the requirement that when distributor driven gear wear is discovered, the distributor drive gear (camshaft) must also be replaced. The reason for this is that the two gears wear together in a pattern and when only one of the pair is replaced the likelihood of a repeat failure is very high.
In spite of this requirement, Cadillac continues to receive warranty claims indicating that only the distributor driven gear was replaced. The claim history frequently indicates a later repeat failure. In the interest of customer satisfaction, Labor Operation J4520-B (Distributor Driven Gear Replacement) has been cancelled. Operation T6135 described in Bulletin T-86-79 must be used for this repair.