Thread: Gearbox issue
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Old 11-04-23, 09:02 AM
Geoff Dowdle Geoff Dowdle is offline
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Join Date: Jul 2008
Location: Sydney, Australia
Posts: 416
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Christian,

From the gearbox number BW CR9/314 I assume it is fitted to an Arnolt Bristol.

If new Syncro rings have been fitted without checking the distance between
the 3rd and 4th ring it is possible that the Syncro ring does not have enough clearance to the gear and once engaged it could be come difficult to release from the tapered cone of the gear. Are those Syncro rings actually the correct ones for a Bristol ??
If this is the case the 3rd gear might need setting rearward a little and the input shaft moved forward a little .
The selector rod might then need shimming to centralise the fork in the middle of the movement of the selector rod.

The front bearing of the input /drive shaft should be a slide fit into the bell housing and should not have any Loctite on it . This bearing just helps
the alignment of the input shaft and takes almost no load.
Note all the bearings of the gearbox should not have any Loctite used .

Another tip is that the long cross bolts bolts of the main case should just be
nipped up to 40 inch lbs (not 30 foot lbs which can distort the alloy case and bearings ).

A further tip is that most modern bearings with a circlip are supplied with a thinner circlip than the groove in the bearing and groove in the main case .
This over time can allow the shafts and bearings to move in the case .

A Bristol gearbox rebuild should not normally be undertaken by a owner without experience with these gearboxes.

I hope this helps a little but it is very difficult to advise you without seeing the gearbox .
Good Luck
Geoff
Sydney/Australia
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