Idler Gear - Setting End Float
A fairly crucial part of how the idler gear operates is its tolerances and
running clearances.
part numbers: 22A1545, 22A1546, 22A1547, 22A1548, 22A1549, DAM4822, DAM4823, DAM4824, DAM4825, GUG705563GM, AAU8424, ADU6033, CCN110, 2A3643, 22A152, 53K547,
Terminology:
DTI - Dial Test Indicator
End float is a continual problem as folk either ignore it through ignorance or lack of accessible information on how to do it, or belief special tools are needed. Also, later factory assembled engine units (from about 1992 onwards) were built up using whatever shims and thrust washers were available, since Rover were not making regular orders for all shim/washer sizes due to the forthcoming end of production. Consequently, many units left Rover with incorrect (usually too big) clearances. The idler gear was no exception.
Too tight a clearance and the idler gear will either seize solid when it gets hot, or destroy the thrust washer thrust faces in the comparably soft aluminium gearbox and transfer gear housing.