Stuck Solid Speedo Sensor on the Rear Diff?

[ratazzi]

Hi there,

My Speedo is not working and i have come to the conclusion that the gap of the sender unit onto the diff housing is too wide (i can fit my finger between it)!

I have therefore tried to turn the bolt to reduce the gap but it is stuck solid. Any ideas on what to do now, i.e how do i undo it?

Any help would be appreciated?

Thanks

[paulathome]

Hi there.
I had the same problem about 3 weeks ago when I changed my sensor.(speedo stopped working)
The gap between the sensor and the toothed wheel should only be about 9 thou.
Have you undone the locking not on the sensor? I assume you have.
Its is a swine to adjust as the sensor corrodes to the bracket and siezes solid,
so the best way is to remove the whole bracket with sensor from the diff.

The bracket is held to the diff by two bolts, one at the top the other at the bottom.
(13mm from memory)
Then put the sensor and bracket in a vice and heat with a blow lamp until the sensor
becomes loose enough to remove. (apply plenty of WD40 or similar)

You will probably find that the sensor is knackered anyway as they are renowned
for being unreliable. (cost about 40 quid from TVR)
If you manage to free off the sensor without damaging it, refit to diff and adjust gap to 9 thou between the tip of the sensor and the toothed wheel on the half shaft, ensuring the toothed wheel does not actually touch when you rotate the road wheel.

Good luck,
Paul.

[sparkythecat]

Have you managed to loosen the lock nut, or is that seized as well?

I wire brushed the threads on the sensor then soaked the whole thing with WD40 and left it for 3 days before I tried to loosen it. Came out easy.

[sam gamgee]

Hi, might be different unit to one in photo. Dod mine today, can fit finger (almost) between my gap (ahem!). Also, no adjustment on mine (`94 griff) so could be why you cannot move it....removed mine, cleaned surfaces and lo and behold speedo working again!

Dave.

[ratazzi]

Thanks for your responses.

I think i may have the same type of sensor as Sam gamgee as there did not appear to be an adjustment bolt?

Sam gamegee - how did you reduce the gap after cleaning it up?

However i will try and remove the whole sensor from the Diff so i can have a good look at the sensor in more detail.

I will let you know how i get on!

Thanks