Bronze face Speedometer Repairs

[myoldjalopy]

Hello peeps. I have been given a spare bronze face speedo that I have tested and it works fine. BUT - the green oil warning lamp jewel is missing and the little stop pin for the needle is loose. I think the stop pin is somehow held in place by the jewel fixing. I can obtain a new jewel but not sure how to dismantle the speedo to do the repairs. I have the outer chrome ring off but can someone advise:

a) How to remove the needle - is it as simple as unscrewing the knurled end and prising off the needle?
b) If the two small screws either side of the needle are undone, it appears the middle part of the face will then remove, but I think the tabs that hold the face on will need to be bent back as well so that the face will then come off so I can fit the jewel and the stop pin back in place. Is that correct?

Advice welcome - I want to repair this and not damage it further!

[myoldjalopy]

By chance today, I met someone at an autojumble who had a partially dismantled speedometer.
a) the needle simply pulls straight off, the knurled end is not screwed on, it is part of the design
b) the face does come off after the tabs are bent back
So now we know!

[philipkearney]

Thanks for sharing that update My Old Jalopy, that's really useful. I have to tackle a gold faced speedo over the winter time, so good to know how to dismantle one without (hopefully) breaking it !

[myoldjalopy]

The green jewel I need is out of stock at the moment so I'm waiting on that before I start in on the speedo. But I will update again when I have the jewel and have done the job - unless you get to yours first!

[myoldjalopy]

All done now. Basically, the chrome bezel with the glass is crudely fixed to the main housing, and comes off by prizing open the areas on its circumference where it has been bent/crushed down to secure it - and then pulling it off. Then the needle can be pulled off. It did not come off at first so I removed the knurled end and pulled again - with my fingers - and it came off. I suspect the knurled end piece tightens the needle on the shaft as you screw it down.....
Next, unscrew the two little screws on the middle circular piece - the bit that has a slot to make the odometer reading visible - and it just lifts off with its metal backing plate.The face or dial has a couple of points where it is fixed to the main casing by little bent over tabs. These are soft - I suspect aluminium - and bend back very easily so the dial can be lifted off. The exact position of this part is ensured by two tabs that slot into small, rectangular recesses.
I was then able to fit the new jewel, put the loop of the loose needle stop pin in position around it behind the dial, secure with the little washer that slips quite tightly over the 'neck' of the jewel and fit a small piece of electrical wiring sheath over the neck. This is to ensure all the light is directed through the jewel, rather than illuminating the dial. Originally, these were small bits of rubber tubing, but I found some old computer cable, the sheath of which was exactly the right size to fit snugly once I had pulled out its inner wires.
If you want to go further, the two screws on the back of the speedo will allow this. I did do this out of curiosity and was then able to clean up the cable driven worm gear and its little fibre gear, as they had a lot of black grease on them. I then gave them a very light spot of fresh grease.
It was all pretty straightforward and all went back together easily, you just have to be careful.

[svenedin]

Excellent work! I was at a classic car meet this morning and I just happened to be talking to a chap who used to work repairing motor car instruments having worked for Smiths and then Revue Thommen. He would have been the man to ask but you had already done it!

Stephen

[myoldjalopy]

Thanks. It wasn't too difficult, just a bit fiddly. Contrary to what the man at the autojumble told me, the knurled end piece of the needle does unscrew. But I think the needle on his was loose anyway as he just pulled it off, knurled end and all, to demonstrate. His didn't have the chrome surround and glass either.

[panky]

You probably already know this but when refitting the needle it should be aligned with the small dot, or dash, on the speedo face that's printed on the 'wrong side' of the stop pin, then flip the needle over to the correct side. This will give the correct tension on the spring and give the most accurate reading.

It can be seen here just by the H/B light

20140923_165929.jpeg (517.48 KiB) Viewed 57059 times

[myoldjalopy]

Aaargh, now he tells me! No I didn't know that. The gold speedos don't have that mark, though. Well, it will be an easy fix, if I get round to it. Its a bit immaterial anyway, as its the wrong type of speedo for my car. With it missing the oil lamp jewel, I just wanted to make it good again....