Speedo not working at gearbox end.

[chesney]

Apologies if this has been covered before, but I couldn't find reference to my problem using the search facility.
Drove my Morris Traveller to France this week from Yorkshire, somewhere around Derby-way on the M1 the speedo started flickering between 20/30mph then died. I presumed a broken cable, but pulled over at a services to check behind the speedo head to see if the cable had slipped off. It hadn't so I continued on my merry way, and made it to France with no problems, other than the fact the speedo never moved an inch, nor the odometer.
Today I got a chance to look at it, so I took the cable off at the gearbox end and ran it using an electric drill in reverse, with an assistant checking the speedo. It ran at 50mph and wet up .2 of a mile. Reconnected the cable and tested, no change. Consulted the manual, then took out the plastic housing and drive gear, which looks undamaged, reinserted and reassembled. It worked up to 15MPH, and about 20ft, then gave up again.
Some history on the box, came out of a car I used daily, speedo was fine, then took it out and had it rebuilt, then put in the Traveller. That was approx. 1000 miles ago, and the first problem I've had with it.
I suppose I should be thankful that this is the only problem I've had in getting it to France, but this one problem is doing my head in. I suppose it could still be a broken cable that I'm pushing together when using the drill, but I doubt it. Any suggestions gratefully received.
Thanks in advance, being away from Britain makes it more difficult to get parts, so I'm trying to sort it without resorting to replacing everything and paying needless carriage!

[MarkyB]

How did the gearbox end of the cable look?
The ends and the bit they fit into can get rounded off and not drive properly any more.

You should be able to slide the inner out and examine it for breaks.

[chesney]

The inner had a tapered end to it, which looked stock but I suppose could be wear. My dad is coming up in two days with a new cable (not specifically for me, he's down this way anyway) so I'll probably just fit that one and either keep the old one as a spare if it doesn't work or chuck it if it does.

[bmcecosse]

The nut inside on end of the mainshaft will be loose and so the scroll is not turning.......

[mike.perry]

Roy,
How do you manage to read and comment on all the topics average 5 mins apart?
Have you unpacked your suitcases yet?

[chesney]

Bugger, well if the new cable can't solve it it could be an angry email to a certain gearbox rebuild company!
Does anyone know if you can gain access to said nut by removing just the remote housing on the gearbox? Trying to see whether it would be possible to replace it with the gearbox 'in situ '.

[bmcecosse]

I dunno - maybe if you take the speedo drive out you will be able to 'centre punch' the nut round to tighten it enough. You'll certainly find out if the scroll is loose....
@ MP - I travel light with Ryanair - so no 'suitcase'.... just a small rucksack - and indeed it is not unpacked yet!!

[chesney]

Pulled the speedo drive out again today to reassess the situation. Bit of a pain as the lovely 'Le Tronquay' stamped bricks in the barn are covered in oil now, but I suppose I shouldn't be anal enough to be cleaning the bricks in the garage/barn.
Upon inspection, I can't move the scroll itself, and with the box in 4th and handbrake on (axle raised on stands) I can't move the scroll with the pinion fitted either, so hopefully not that either. I've brought the pinion in to clean and check it, it appears, as markyb suggested, the pinion 'rod' has worn near oval, difficult to see when full of oil, but definitely worn. The cable is also worn, it's now tapered more on one side which I suppose is concurrent with the cable being on an angle. Had the inner out today, which is in vgc. Another test, slotting the pinion into the plastic bush and attaching the cable, showed the cable worked intermittently, but of course me twiddling it with my thumb is different to the gearbox driving it at 10/20/30+mph... So I'm to try a new cable and drive, unfortunately I can't find a new pinion online, only second hand ones from Bull Motif. I have a few spare gearboxes I can liberate spares from, but out of interest, can you buy the pinions new?

[bmcecosse]

Well done - that's certainly an easier fix !

[chesney]

Thanks to all for your advice.
Managed to gain access to my spare drive pinions and new cable, so fitted them today. Both came from 948 gearboxes, one was the later plastic, one the earlier metal version, with metal gear wheel. This was in the best nick, and so was the one I fitted. The Workshop manual mentions the (modified) pinion drive (aka later plastic) as being interchangeable, I assume there are no ill effects in using the early pinion in a later box? So far as I can tell, the change from metal to plastic was to simplify the oil seal, and as a cost saving measure? In any case, the speedo reads rock steady, which was a nice surprise, so I assume no ill effects in using. Did consider using the metal pinion in the plastic bush but realised it was a pointless exercise.