I am overhauling my 1946 B31 gearbox and have fitted a new Layshaft sourced from Australia. All is well but I cannot get the speedometer driven gear to seat properly and it locks up the gearbox once I fully insert the retaining bush. The parts list shows different versions of the layshaft and the driven gear for the B31 and B32. Does anyone know what the difference is between the two versions as I am beginning to wonder if I have a mismatch of layshaft and driven gear.
Keith L
Hi,
Can you compare the new with the old?
Best wishes...
The layshafts looked the same apart from an extra oil groove or two. I might have to take the new one out again to compare the speedo driving gear at the end.
Keith l
Hi,
I have a B31 layshaft on the bench, if you want I can post a few images to compare?
Best wishes
Thanks but I have the old one for comparison.
Some progress thanks to your inputs. I have removed the inner case and the gears to compare the lay shaft with the old item and found no perceptible difference. I then tried fitting the speedo drive with the gears inserted but with no inner case fitted and everything was Ok. However when I attach the inner case, the tightening up of the gears returns.
I had replaced the layshaft gear, due to broken teethe, earlier in the restoration and then later identified that the lay shaft was bent which is why I replaced it. There is also witness marks on the main gearbox case on the edge just before the join with the inner cover.
I am left wondering if the bushes are the problem. Any further suggestion would be gratefully received.
Keith L
If you have replaced the layshaft then obviously the pinions will have been switched. I don't know if any of the pinions are pressed on like the A10 but if not fully pushed home then they will bind on the bushes when the cover is put on as there will be insufficient clearance.
Hi,
Try assembling with the layshaft only, without the packing washer, if you have a problem could be bushes. If it turns freely try again with the packing washer if you have a problem it could be an end float issue.
In the later box it is built without a gasket and adjusted for minimum end float on both gear and selector shafts. The 10 thou gasket then sets the end float, is your gasket too thin?.
Hope this helps
Best wishes...
Thanks, I will try both of your suggestions. Much appreciated. - Keith
I checked the 18T and 21T gear on the lay shaft and I believe it is inserted fully home.
Installing the lay shaft alone with the inner cover on, the box turns fine without the speedo drive installed but snags badly when the speedo drive is installed. Bearing in mind that the B32 had a different part number for both the lay shaft and the speedo drive, I wonder if I have a mismatch of parts or is it just that a new lay shaft and old speedo drive are not compatible?
Thanks for any further observations you can offer.
Keith L
Hi,
Maybe worth asking on this forum:
http://www.wdbsa.nl/
Someone there might have had a similar issue.
Best wishes...