47 replies to this topic

[maieth]

You can replace the worm with the engine in, but you will need to remove the LHS engine mount and bracket, plus the adapter block from the side of the gearbox. You will then see the cover plate held in with two 1/4"unc screws. Remove that extract the 5 tooth and replaced with a 6 tooth...

and if you don't have one....

 

http://www.guess-wor...play.htm?id=325

 

That's great. And your worm drive's a LOT cheaper than minispares.  If I have a go at this, I should be able to pick up both the worm and pinion from you.  Don't suppose you can do a decent speedo cable too?

 

Idiot questions now:

1) LHS engine mount - when looking at the front of the car, or sitting in it? (see? idiot) Guessing this is to get a bit more access, whichever side it is?

2) Adaptor block....     I straight up have no idea what this is. Sorry. 

 

At least the cover plate makes sense. I spotted that on diagrams earlier.

 

How many Haynes spanners you reckon this is? 

[Guess-Works.com]

3 haynes spanners

 

1. which side is the steering wheel on ?

 

2. that'll become obvious when you get there.

 

speedo cables are not on my stock list because there are so many different ones

[maieth]

 Right. I'll give this a go tomorrow before it starts to p*** is down. If I manage to get the spindle out, I'll get an order in for the drives.

[maieth]

5 teeth, woo!

 

 

Was quietly dreading that the information I put into the calculator was wrong somewhere and I'd find it had 6 teeth after all.  Big sigh of relief.

Guessworks, you've been a huge help on this, thank you.   I'll put an order in for the replacement drives in a bit.

 

On closer inspection of the part listed on minspares, I think the speedo cable is okay.  Despite having a square socket, the almond profile of the cable allows it to seat very snugly in the pinion drive and I can't get it to slip.  If anyone knows better on this, let me know.

[maieth]

3 haynes spanners
 
1. which side is the steering wheel on ?
 
2. that'll become obvious when you get there.
 
speedo cables are not on my stock list because there are so many different ones

Done!
Just closed the bonnet having fitted the new drives and put it all back together. So much easier to reassemble all the speedo parts with the engine mount out of the way. Fingers crossed,we should get a working AND accurate speedo reading next time we take her out.

Guess-Works.com, thanks in particular for your guidance on this repair and for getting the new drives out to us quickly.
(I don't suppose you've got any interest in buying back the 5-tooth worm drive? Useless to us now and someone's more likely to want one from you then from us)

Edited by maieth, 07 March 2015 - 01:49 PM.

[maieth]

So SWMBO finally got back on the road yesterday and is thrilled to have a functioning and ACCURATE speedo!

Thanks to all for the advice.

 

SOLVED!

 

[Spider]

Good result, awesome.

[red81]

Hope you don't mind me re opening this one, but I've read all the other posts and am still at a loss.

 

Speedo not working on my newly re- installed 998 A series engine;1981 mini with 10" wheels.

 

Speedo not working, so checked speedo, reverse drill, all ok.  Bought new cable and pinion installed still not working.

 

I  jack up one side, remove plugs and find I can't turn the front wheel in gear, this procedure is stated on other posts to see if the pinion turns, should I be able to do this? The car runs fine but has only be run for half a mile to warm the engine after a head gasket change, so I take out the newly installed pinion out and find it's chewed, but still can't turn the wheel whilst in gear?

 

The only thing that's left is the speedo spindle (drive) in the box, Spider had one that was broke, so is this an engine out job, or can I pull it out through the speedo drive plate (please say there is an alternative)

 

Any other ideas warmly welcomed.

[nicklouse]

If you have one wheel of the ground and the car in gear you will be trying to turn the engine over.

[sonscar]

There is some variability in the cable and drive,I had a cable with a flat formed on the gearbox end,useless lasted less than ten metres.It was replaced without question by the supplier with a square ended one again useless as it was too large to fit into the drive gear slot.Reused the old one and fitted perfectly but had the fettle the speedo end as the plastic bendy clip has broken.
Just like most parts,some are utter trash.Steve..

[Ethel]

You're starting in the right place.

 

The speedo is driven off the end of the mainshaft, so turning the final drive  (aka diff crown gear) should turn it whether it's in gear or not. Turning one road wheel, while the other is held still turns the crown gear half as fast as the turning wheel.

 

It ought to be possible to get at it all with the engine in, but it's obviously awkward.

[red81]

Ethel

If I lift both wheels off the ground I can feel the diff turning.  But the speedo pinion does not turn when I do this.  So how can the main shaft turn, which turns the speedo drive spindle, without turning the pinion?

 

Is there a way of testing the speedo drive spindle; i.e that it is turning without the pinion?

 

Nicklouse

When I try to turn the wheel its as if the gears are locked, I've tried 2nd and 4th both the same with plugs out, should I be able to turn it, I'm beginning to think its a stupid question.

[sonscar]

Turn it in neutral,you are trying to turn the engine,it is doable with the strength of Hercules,Poke a slim electrical screwdriver into the drive and feel for it engaging.Turn wheel in neutral and watch carefully,Steve..

[red81]

Thanks Steve i'll try that and have a play, steve i

[Ethel]

Ethel

If I lift both wheels off the ground I can feel the diff turning.  But the speedo pinion does not turn when I do this.  So how can the main shaft turn, which turns the speedo drive spindle, without turning the pinion?

 

Is there a way of testing the speedo drive spindle; i.e that it is turning without the pinion?

 

Nicklouse

When I try to turn the wheel its as if the gears are locked, I've tried 2nd and 4th both the same with plugs out, should I be able to turn it, I'm beginning to think its a stupid question.

The diff turns the wheels equal & opposite - if you're turning one forwards the other should be going backwards. If it can't because it's sat on the ground, then the one you're turning will be going forward, relative to the final drive, while the final drive goes forward at half the speed - meaning the other wheel is going backwards relative to the final drive

 

1(+1) -1(+1) = 0(+1)

   2         0          1

 

Turned wheel

Other wheel

Final Drive