Right Angle Speedo Drive

[stuartgb100]

Looks like the drive unit is faulty.

I can drive the speedo using a drill attached to the drive unit end of the speedo cable when turning counter-clockwise. Presumably this points to the drive unit being faulty?

If so, then how do you remove the drive unit?

BTW, whilst undoing the cable from the drive unit, I found that the drive unit itself can rotate ..... is that usual, please?

Regards,
Stuart.

[Dave-M]

Stuart,
The right angle gearbox is secured to the box by a forked shaped clamp. It is not unusual for the unit to be able to rotate.
To remove the unit just undo the bolt holding the clamp to the gear box and pull the right angle unit from the gearbox.
If it is knackered I think the same unit was used on some MGB's and Triumph gearboxes. I am not 100 certain on this so perhaps someone could confirm.
Regards
Dave

[Dave-M]

Stuart,
The right angle gearbox is secured to the box by a forked shaped clamp. It is not unusual for the unit to be able to rotate.
To remove the unit just undo the bolt holding the clamp to the gear box and pull the right angle unit from the gearbox.
If it is knackered I think the same unit was used on some MGB's and Triumph gearboxes. I am not 100 certain on this so perhaps someone could confirm.
Regards
Dave

[stuartgb100]

Dave,

Thanks for that. Seems the said bolt was hidden out of my sightline.

Hopefully someone will post re alternative parts, otherwise I'll order from Sue Miller.

OTH, is it a repairable item?

Regards,
Stuart.

[SADLOTUS]

Speedycables can do it

[stuartgb100]

SadLotus,

Many thanks for that.

Regards,
Stuart.

[steveb1]

On My +2 the old cable seized and when the cable was replaced the speedo still didn't work. I found that inside the angle drive was a short flexible rod, square end went into the gearbox round end into the angle drive. When the cable seized this flexible rod seem to be designed as the "weak link" to avoid damaging the drive mechanism. I simply pulled the rod out of the angle drive straightened it up and refitted.

Hint: It's VERY tight undoing the bolt on the retaining fork, but when putting it back together you can refit the fork first, then the adapter for the angle drive and finally the angle drive.

[steveb1]

On My +2 the old cable seized and when the cable was replaced the speedo still didn't work. I found that inside the angle drive was a short flexible rod, square end went into the gearbox round end into the angle drive. When the cable seized this flexible rod seem to be designed as the "weak link" to avoid damaging the drive mechanism. I simply pulled the rod out of the angle drive straightened it up and refitted.

Hint: It's VERY tight undoing the bolt on the retaining fork, but when putting it back together you can refit the fork first, then the adapter for the angle drive and finally the angle drive.

[stuartgb100]

Steveb 1,

Thanks for that. I was going to ask what were the chances of repairing the right angle drive, so there's a pointer already.

Looks like I will find out more this evening, as long as it's not howling a gale right through my garage (again).

Regards,
Stuart.

[SADLOTUS]

The flexible drive on my angle drive refused to come out on the gearbox side, don't know if others found this but be careful when pulling the angle drive off and the flexible drive out that you dont pull too hard and distort it - it's a wound cable compressed into a square shape that will pull apart like an overstretched spring and I found it impossible to reshape back!

[stuartgb100]

SadLotus,

Another pointer, thanks.
Guess I better take it easy then.

Better get cracking before I lose what little enthusiasm I have for working in the garage tonight.

Regards,
Stuart.

[stuartgb100]

Okay, the speedo right angle drive unit is out, without too much melodrama.

I've part stripped it down and attach a few pictures.

The bendy, wiggly bit has 'flats' at one end (ie a square drive). The other end is just the springy bit ......... so is something missing here?

Regards,
Stuart.

[tower of strength]

looks like the drive has sheared off to me. The square drive cable should be fixed into the housing and should spin freely(a bit of drag obviously)

Triumph spitfire/gt6 and other overdrive jobbies are the same and a bit cheaper/easier to find than Lotus ones.

regards

Mark

[stuartgb100]

Right, that was my guess, not having seen these bits before.

So the question begs ............. where is the 'sheared off' drive end now?

Is it likely to be lying in the bottom of the 'box' ?
Or
Still in the housing of the box ..... ie stopping a new one from being fitted?

?????????

Regards,
Stuart.

[ppnelan]

Stuart,

If you unscrew the turned aluminium 'housing' from the gearbox end of the drive, you should see a steel bush inside the drive. The cable should be fixed inside this...

I had one which had the bush 'spin' in the drive, and had also twisted the cable stub due to the speedometer seizing. If you can prise out the bush, it is possible to fit a 'new' cable stub made from the end of an old speedo cable with the flats on. I think I soldered this into the bush, then refitted it with some Loctite Bearing Fit.

Make sure you check/lubricate the speedo cable & speedometer though, otherwise you'll probably get exactly the same result again...

Good luck!
Matthew