Rear Axles….What Fails and Why (PART 1)
N.W.Geeson ver 1. 2006

Page 2/5

These images illustrate one of the major failing and weakness of this early triple bearing assembly. Fig 9 shows the early bearing and bearing housing. In this instance the housing has been copper plated to prevent rust, this housing is used for demonstration purposes only and the copper should be ignored. FIG 10 shows how easily the first section of the bearing can be inserted into the housing, this also applies to the last section of the bearing. The reason for this is that only the centre segment of these bearing is designed to contact the bearing housing. This design lacks stability at the main bearing end of the pinion and places great reliance upon the integrity of the small pinion nose bearing. Luckily for owners of the later models R-R realised the error of their ways and utilised taper bearings.

Continuing with the theme of sludging problems, the following few images are offered for the owners delight. Firstly Fig 11 is shown to illustrate just about the cleanest Bentley MKVI axle I have stripped in the last few years, the moral here is that your axle is likely to be in the mould of the axles shown from Fig 12 onwards where the captions explain all!

To recap, it has been explained how rear wheel bearing wear can have a detrimental effect on rear axle differential bearings, how the axle oil can overheat and the effect on oil additives, and how dirt enters the axle. Now we can see, using the following images, what axle damage occurs as a result of this foreign material being allowed to repose in the differential. If someone had changed the 1.5 pints of EP90 oil every year, instead of the ridiculous 20,000-mile period suggested by the factory, the problem would not occur. Unfortunately the clock cannot be turned back and we have axles failing at 70,000 miles instead of the 500,000 miles that they are capable of completing.