Fluctuating Speedo

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owen1183
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Fluctuating Speedo

#1 Post by owen1183 » Thu Jan 18, 2018 11:45 am

Hello all, Took my 2055S out last weekend after a lay up of a couple of years and the speedo fluctuation has gotten really bad. Previously the needle would fluctuate between 25 & 35 when doing about 30, so I replaced the speedo cable. I made sure that the cable ran with nice big sweeping bends, and was securely attached.

Now my speedo indicates upto 90 when doing about 20mph......

when I fitted the new cable, I fitted it straight from the packet.. I.E. no grease...

I intend to remove the gauge and pull the inner out into the cabin and grease with Castrol moly grease and re-fit......

Hopefully should cure the issue?
76' P 2500S in Honeysuckle with Manual O/D

Mike Stevens
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Re: Fluctuating Speedo

#2 Post by Mike Stevens » Thu Jan 18, 2018 4:20 pm

This can be a common problem when the angle speedo cable adaptor is going faulty. However, your car should have a 'J' type overdrive and they didn't use the angle adaptor (on on the big saloons anyway)!

Check that you've not a sharp bend in the cable route. Putting some grease down is not a bad idea, but not so much that it can get out the top and into the speedo.

Have you also checked that the speedo input drive is smooth and not stiff?

Cheers,
Mike.
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owen1183
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Re: Fluctuating Speedo

#3 Post by owen1183 » Fri Jan 19, 2018 8:09 am

Hi Mike,

No I haven't checked the input drive on the speedo. When I take the dash panel out I'll grease the cable (as per smiths maintenance guide it should be greased every 10k miles) and check the speedo input.

I really hope its not the speedo, as to replace it I'll loose the tacho history
76' P 2500S in Honeysuckle with Manual O/D

Charles H
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Re: Fluctuating Speedo

#4 Post by Charles H » Fri Jan 19, 2018 8:57 am

Sounds like the speedo head. A couple of drops of very thin machine oil will help it. Not too much though!! Alternatively the speedo can be serviced/refurbished at a company like Speedycables in Swansea.
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Re: Fluctuating Speedo

#5 Post by Mike Stevens » Tue Jan 23, 2018 10:17 am

Well, you can 'clock' a replacement speedo to indicate the same as the replaced item. I have done it before.

However, a refurbished item as Charles suggested could well be the best route. I would expect them to leave the odo reading as it was.

Good luck with the greasing.

Cheers,
Mike.
(South Oxfordshire)
Register Member No 0355
1967 Herald 1200 Convertible rust should be white
1971 2.5PI Saloon Sapphire blue
1973 2.5PI Saloon rust some Honeysuckle
1973 Stag French blue
(1949 LandRover was blue should be light green!)

Clifford Pope
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Re: Fluctuating Speedo

#6 Post by Clifford Pope » Tue Jan 23, 2018 2:36 pm

I had that once when I over-greased a cable. It worked its way up the cable and into the head. If you get dirt or grease between the rotating plate and the stationary, the needle gives sudden alarming flicks up to full scale. After dismantling and cleaning it worked perfectly.

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