Jumping out of second gear on overrun

[ukmax]

Hello again,

My 1935 LeMans special speed is jumping out of second gear.

I remember reading an article (I think in the Singer Owners Club magazine) which suggested that this problem could be caused by wear on the leading edge of the teeth of the second gear. I seem to recall (but may be wrong) that one proposed solution involved machining the gear back to fresh teeth and inserting a spacer behind the gear to move it forward.

I do have the equipment and knowledge to carry out this work or could of course replace the gear if one is available.

Does anyone recall this article and can post a copy, or can anyone suggest another possible cause/solution please?

David

[jeans_old_man]

Hi David,

It might be worth checking that there is nothing preventing the gear from moving fully into the detent - wear on the gear lever ball, loose clamp where the remote tube enters the gearbox top, misaligned gate or, heaven forbid, a loose fork.

That said the problem is most likely to be the bronze bush that 2nd and 3rd runs on. On later boxes this bush is held in place by a nut at the front of the mainshaft. A flange in the middle of the bush acts as a spacer and positions the two gears. Unfortunately, this flange nearly always breaks off. This is not usually a problem if it remains as a washer but sometimes it disintegrates.

The photos show a bush that I replaced with a home-made one. The one I made is the one that disintegrated so now I am running on the original. If anyone has a 'fix' for this I would like to hear it.

[telco.2]

I'm next in the queue for a 'fix'!

[ukmax]

Hello Brian,

Thank you for your informative response, I shall certainly check all of the possible "faults" you have mentioned. You seem to indicate that a fault with the selector forks could/would be a particularly difficult problem could this be because replacements are not available?

I note in particular the probable problem with the bronze bush/spacer arrangement, is this correct? Did you machine the replacement from the solid?

I could really do with trying to get hold of another gearbox either to use or to rebuild, rather than taking my car off the road as it seems that the repair could be a lengthy process if parts are difficult to obtain.


David

[jeans_old_man]

Hi David,

A loose fork can be disastrous because a loose screw may drop through the gears (speaking from experience!).

I got someone to turn me a new bush from a bronze casting - the man who sold it to me said it would be cheaper than a solid bar. Nowadays I believe you can buy cast bronze tube - have a look at metals4u.

I have considered making the bush out of two parts - a straight tube and a separate spacer but havn't tried it yet. I bought a standard bronze bush and thrust washer but they are sized as a press fit on the outside and a bearing fit on the bore which is the opposite way round to what is required.

The car is running well with the original bush and given the effort required to get the gearbox out of a '35 four seat (rear footwell, seats, floor, propshaft cover, propshaft) I am in no hurry to experiment.

Good luck finding a spare gearbox - they do occasionally turn up and fortunately the ball bearings are readily available.

[ukmax]

Hello again Brian,

Ah, I now understand your comment about the forks!

I've never stripped a Singer gearbox and I can't find a workshop manual or parts book for my model anywhere on line so I have no idea of the configuration. However, looking at your photos, I can't see any reason why this bush and thrust could not be made as separate parts. In fact, I found a parts diagram for a 1946/49 Singer 9 gearbox and it shows the bushes and thrust washers as separate parts.

David

[John Simister]

Hi David, among my stash of somewhat used pre-war Singer spares is what I'm fairly sure is a Nine gearbox. Would you like me to extract it from the shed and report on its condition/suitability? It might make a good basis for a rebuild.

John

[ukmax]

Hello John,

Thank you, that would be marvellous. Please PM me with details once you have ascertained it's existence. You don't have a steering box as well do you?

Kind regards,
David

[John Simister]

Will do, this coming weekend. No steering box, sadly – there was one, in desperate need of a rebuild, but it went to the Netherlands.

[John Simister]

You have a PM re my spare, and promising, gearbox.

John