Saturday, 24 September 2011

Preparations for the return of the DHC

At the moment the DHC is still not back home, estimate is that she’ll be back home early next week. But I haven’t been completely idle. As I don’t want to take of the gear box for the next ten years or so, I have decided to go for a rebuild gear box. So last week I went through my spare gearboxes in search for the most suitable ‘box for a rebuild. In the end I decided on the original ‘box that was fitted to GB-16-YP at Canley early in 1980. A bit in doubt as to its serial number though ...

And although this ‘box has covered over 200.000 kilometres, it felt to be in fairly good condition, with hardly any play on the bearings. So first thing to do was dismantle the ‘box, to get a clear picture of the internals. I started with an inspection of the oil that came out if it. Was good to see that is was fairly clear and didn’t contain any brass contamination ...

With the oil drained, it was time to start dismantling it in earnest. First part of the ‘box to remove was the rear extension containing fifth gear and the oil pump, which was fairly easy once the rear flange was removed (easy thanks to a proper air powered wrench).

Was good to see that (again) the internals of the oil pump were in fairly good condition, especially regarding its high mileage. And the first gears (fifth) to come into view also looked in good condition. Only some slight play of the gear on the main shaft, so some new needle bearings needed here.

After everything from the fifth gear was removed, it was time to separate the main casing from the mounting plate. Again no hidden horrors. All gears look in good condition with no noticeable play on the main shaft.

Only real sign of any wear was visible on the selector forks. Will see if I can get pair of proper (original) new ones, otherwise these will be reused as they aren’t that badly worn.

All in all this ‘box looks like a good choice for the rebuild. The only parts showing real signs of wear are the main bearings. Although there was no noticeable play, they all have visible signs of wear on the outer races

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