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Land Rover Lwt - Speedo overhall


Question

For some reason the speedo in my Lwt stopped working but it wasn't the speedo cable, as with a spare speedo installed everything worked as normal.

Anyway I decided to take the old speedo out and take it apart. The first thing I noted was the inner surfaces of the casing were painted light blue and off white. But why was the inner surface painted like that as they are not seen when the speedo is put back together and installed in the Lwt. Is this original to the factory? Its made by Smiths and I'd like to restore things as near to factory fit as possible?

On the rear of the casing under the makers name it says 'None O Jewels' - what the does that mean?

When I took the speedo apart the glass was held in place in the inner rim by a substance resembling coal - whatever it was had crystallised, and I would appreciate knowing what's best to use that won't ooze out when the glass and outer rim are put back in place and spoil the look or turn to 'coal' in a year or two.

Lastly to test to speedo I took a spare speedo cable part number 579435 and connected the gearbox end to a cordless drill.  However despite using the correct speedo cable (i hope) I could not get it to engage in the back of the speedo itself and i wonder why in my speedo mechanism there is a recessed ridge all the way round the drive (just down from the yellow part in the attached photo) that doesn't have any way of connecting in to the speedo cable end. I guess the speedo cable needed to be pushed further in but I could not move it in any more so the cable did not engage. Why?

Thanks

 

986103029_SpeedoCasing.thumb.jpg.9f59e91b2917770bebe6af90f51fe80a.jpg 

Speedo cable end.jpg

Speedo from Lwt LR.jpg

Edited by LarryH57
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It is a while since I hooked up a speedo head , however - your cable does not seem a genuine Land Rover part.  Non-gen are rubbish at both ends , often the drive end is not square , it is triangular (no names no pack-drill).  The head end (genuine) is grey plastic with a bayonet fix.  IIRC a little trigger with a catch hook then engages , the 'recessed ridge' you mention - the hook engages in the groove anywhere 360 degree.   I have not checked the part No. you quote but a S3 civvy cable is longer than a Lightweight one , it will work but you need the right curvature & secured to clear the exhaust front pipe.

Miles or Km (miles on inner dial) , depending on timeline , it could be branded Smiths or Jaeger and ISTR  Land-Rover  - all out of the same factory in Wales (after management buy-out - they go under another name).

Jewels :  jewels movement bearings ?    Often Jewels , to a LR person are according to the the small coloured lens jewels . yours should have  1. cold start  2. main beam warning. 3. oil pressure warning.  These vary among civvy / MOD  LR's .  You may even have a re-built head , correct face but movement off another -  a good clue , the  wheel revs per mile will be marked at the bottom, often they are re-calibrated for change to 7.50 tyres.  They are then remarked  on face, very tidy by hand with paint !     Exchange units can be built up to requirements using a mix. of parts.  There are plain head , nil jewel faces, your case could be one of these - don't forget these were used on other car makes too where warnings were all on the instrument panel.

Edited by ruxy
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Posted (edited)

Thanks Fulltilt,

My Lwt was built circa November 1980 and is a 2.26L GS. So I'm told the speedo would be in Kms for that time period, and I'm sure the one I am working on is the original fit and is also in Kms.

Any clues over the reason for the internal colours of blue and white? And also what to use to secure the glass?

As for the spare Britpart cable I own I guess you are correct, it's better for a S3. However by holding the speedo cable vertical with the speedo balanced on top I did get it to work nicely and with the cordless drill set to turn anti-clockwise, I got my speedo to maintain 40 kmph nicely.

I guess its time to reassemble it now.

Edited by LarryH57
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I forget your VRM just now.  Certainly  --HG--  had  Km. clocks fitted, would have to check time-line change point  (IIRC up to 1979 , same as change to electrical grouped instrument cluster) - think it was with a  HF contract. So if your instruments are electrical then I would say original clock head was Kms.

Correct is with 'trip-reset'  - do you have ?      Km =  PRC2605  , I prefer the MPH =  RTC5034  (LR Refr. Nos)

LWT  specific cable = 579435

You need a split rubber bush & P clip to secure at g'box  & another at front end , these are important to maintain correct curvature & stop friction on outer Bowden.

The present OEM manuf. may supply spares direct  ?

https://www.caigauge.com/

Like you , I have opened a few speedo-head and found a rudimentary problem soon fixed.  Not with LR but had zooming pointers to max. out @ 5mph  - found grease gone up Bowden and got in air-gap between the pair of rotating disc (Eddy current) .

Seems you need a new glass seal ?     I used to get them & new glass from some specialist in Leeds - don't know if still in business, there are a few similar in UK who will stock Smiths. Such as Holden Classic & Complete Automobilist etc.  I think to get a new seal then it c/w the glass. Land Rover ISTR non-provisioned items.

 

 

 

Edited by ruxy
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An alternative explanation of the reference to Jewels is that in clockwork watches and high quality clocks it was common to use semi precious stone in tiny pieces as bearings for the shafts that moved relatively quickly. As a measure of quality there would be a marking that proudly announced how many jewels were present. It is possible that early speedometers used jeweled bearings for the needle shaft but the practice died out in the fifties as unnecessary complication.

The coal pretending to be the glass seal used to be rubber. Luckily materials have moved on since then.

I think that the blue inside of the case is to make the night illumination look less yellow and more white than it would otherwise. We forget just how yellow car headlights used to be before halogen ones came in.

David

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Guys one last question!

The attached photo shows (bottom right) two of the three surviving rubber fixings that go over the end of three 'stalks' in the casing that take the Green Blue and Amber lights. I can only guess they are to shield the lights. However these are falling to bits, so does anyone on here know the part number and a source for them?

Also the lenses for the Green Blue and Amber lights look to be held in by a tight fitting washer on the reverse side, but how do these come off as the blue light is broken and in need of replacement?

Speedo Casing and fittings.jpg

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Dear All,

 

There is very little that I will not 'repair by repair'.  I will develop the necessary tooling and capabilities.  But a speedo is too much for me.  Maybe someone who does clocks might be able to do speedos.  One of the very difficult bits to deal with is the spiral spring controlling the needle.

My advice is to send the head to Speedy Cables, Thomas Richfield or another specialist.

The paint on the inside is just to reflect the light around.

John

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Posted (edited)

Well the Speedo works and I am just at the point of reassembly,  and the rubber fixings would be a nice addition and a new blue lense, as it is broken at the back. 

And BTW when the dial is fixed with the correct screws and rhomboid rubber patch  in place the dial face still seems to be slanted. Is this to be a bit more visible to the driver?

Edited by LarryH57
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Hi,

the jewels are on eBay, got to order sone for mine as just stripped the speedo. Not found the rubber grommets yet tho, I might call speedograph and see if they can supply them.

i did wonder about sending it away but funds are getting low with the rebuild lol.


Don

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Don,  let us know if you get any luck finding the rubber grommets. I  am glad I overhauled my speedo as I think it stopped working because of crap in the mechanism as no broken parts were found, so I could have spent good money if I had sent it off. 

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