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Technical Notes and Parts Information

REAR AXLE - Alan Gibb
The Doretti rear axle is a hypoid semi-floating type with a pressed steel cover at the rear of the central casing. This removeable cover allows access to the differential unit and crown wheel/pinion set. This axle is the same type as used on the Triumph TR2 which was itself an uprated Mayflower unit. Most problems involve half-shafts breaking at the differential end, or oil leaking at the hubs and ruining the brake linings.

If replacement half-shafts from another car are to be fitted; only use a half-shaft from the same side. DO NOT use a half-shaft from the opposite side as this will create "torque" in the reverse direction and lead to failure in a very short time. Half-shaft nuts should be tightened to 145 lbs/ft.

Whenever a half-shaft is replaced always replace the bearings at the same time as these are single row ball-bearings and take a lot of stress. Bearing lubrication is via grease nipples located at each end of the rear axle.

The complete rear axle can be exchanged for a more robust later type axle found on the TR3/3A. This axle can be identified by its round tube end flanges with six bolts holding the brake back-plate. Fitting this axle requires using the TR3/3A U-bolts and lower spring-plates to accomodate the larger axle tube diameter. This axle has Girling brakes instead of the original Lockheed items, which means that a new flexible hose is required to match it up with the original tee-piece. Remember to transfer the handbrake cable stop bracket from the old axle to the replacement unit, and it is also adviseable to replace the wheel cylinder rubbers to keep the system clean.

The rear axle number is stamped on the upper rim of the flange to which the rear cover plate is attached. This number has the prefix "TS".

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Ken Yankey © 2001
E-mail: ken@doretti.co.uk
URL: http://www.doretti.co.uk