All Souls Day.

Christopher Carnley · Posted: Wed Nov 02, 2016 6:13 pm Post subject: All Souls Day.

A post for "All Souls Day" after all the witches etc, that the "Saints" didn,t clear away!

This nice little 3 /4 1/2 Speed Model turned up today whilst the owner was supervising the collection of his Lagonda LG45 Rapide G10 gearbox, previously seized on the road,and repaired by yours truly.

I won,t bore you with the details of the repair of the Bentley/Sewell crib of the Derby Bentley box, but the failure was due to the previous installation of an overdrive, by a Midlands cobbler.

The G10 is a "dog", and there was another on the lorry,to work on!

Really nice and very tempting.

David Cocking · Posted: Thu Nov 03, 2016 8:50 am Post subject:

Chris, any detail on what exactly was wrong with the overdrive installation? I am about to fit one to my Derby and don't want to repeat the mistake.

Christopher Carnley · Posted: Thu Nov 03, 2016 10:44 am Post subject:

Dave,

I don,t believe that there was anything substantially amiss with either the G10 or the overdrive before the "cobbler" installed it.

The G10 is a poor imitation of the Derby gearbox of which WO, at R-R for 5 years must have been familiar with, but both Charles Sewell a draughtsman at Bentley Motors and he, made bit of dog in the translation.

This is the Derby main-shaft showing the riveted on 3rd speed driven gear thrust washer/ gear bush.

.

This is the same part on the G10 main shaft.

and the thrust washer.

The poor installation had the rear drive flange drawn backwards loading the 6 splines against the 3rd gear, its bush and thrust washer, the result being the friction welding of the parts together.
That is temperatures above 1000 C. Any oil film was boiled off, the oil pump was useless as the feed was blocked, and the fools had insisted on a case hardened steel top hat gear bush!

It was impossible to press the parts off the main shaft, and only by the cutting and drilling of the 3rd motion shaft was the truth revealed.

Had I not been in contact with a guy in Poole who had his MK VI Special rear axle badly damaged, the repair would not have happened as neither the Lagonda Club have any parts, or any of the specialists.

So be very careful how you install the overdrive, and get it as close to the gearbox as possible, and don,t exert any longitudinal loading onto the main shaft.

David Cocking · Posted: Thu Nov 03, 2016 9:00 pm Post subject:

Ouch, a bit of a mess all round! Many thanks for sharing this Chris, I shall certainly pay very close attention to the axial aspect when I install.