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Speedo not working

Posted: 04 May 2017 18:25
by Monkeyzak
I fitted a new speedometer cable as the old one snapped. Its still not working

Again as always. Any tips?

Re: Speedo not working

Posted: 04 May 2017 21:02
by j.johnson23
I had trouble with mine,I had not pushed the cable into the g/box(5 sp).
I found it easier to put the cable into the speedo first then do the g/box end after.

Re: Speedo not working

Posted: 04 May 2017 21:08
by Monkeyzak
I found access really difficult. Is there an easy way to access it?

Re: Speedo not working

Posted: 04 May 2017 21:36
by saabfast
Its is easier with the car up on ramps but still a bit of a grope job.
I have had the problem both ways. Last year I replaced the speedo cable to cure the flickering needle below 30 mph (which it did not) and did not seat the end fully at the gearbox end so it did not work at all until reseated. Last week I replace the dash lighting with LEDs and had to release that end. Initially it did not fully clip back in and therefore no speedo. Again, took a lot of messing about and groping to get it clipped back in.

Re: Speedo not working

Posted: 05 May 2017 09:41
by busheytrader
Small thin scrape resistant fingers are best but I don't have those......

I had the same issue of the bouncing speedo needle below 30mph after fitting a new speedo cog in the gearbox. I hadn't let the cable seat properly at the gearbox end before tightening the relevant clamp and mashed up the cable.

I ordered a new one for my 1980 DHC but unknowingly received one for the last car's that were fitted with a push button speedo reset. It was a pig to fit on the speedo head and it kept dropping out after a few miles. The correct one fitted first time with a proper "click" at the back of the dashboard with minimal pushing and pulling. I found it easier to fit the gearbox end first enabling the cable end to seat properly, then tackle the other end where it should be a light push fit. The dashboard can stay in place as you fumble underneath but i found it a real knuckle scraper.

Re: Speedo not working

Posted: 05 May 2017 21:58
by Monkeyzak
Ill get it jacked up or on my ramps on Sunday and disconnect and reconnect again. Speedo end seems ok so I'll do it all again

Re: Speedo not working

Posted: 06 May 2017 15:28
by FI Spyder
It sometimes is possible to connect the cable with out the inside cable being in position and it won't auto position. You can check the speedo by connecting a drill to the transmission side of the cable and running the correct rotation have someone check to see if the speedo needle is moving.

Re: Speedo not working

Posted: 19 May 2017 11:01
by Howard_B
saabfast wrote: Last year I replaced the speedo cable to cure the flickering needle below 30 mph (which it did not)

I cured the flickering on my 7 by spraying the drive connection on the rear of the speedo with WD40. Initially it didn't make much difference but after a while the flickering went completely.

Re: Speedo not working

Posted: 21 May 2017 20:12
by Monkeyzak
Gave up with all the other jobs for now till my mechanic mate comes back from holiday.

Looking at the speedo again. I removed the bit to the gearbox and re seated. Pulled the bit off the speedo. Jacked up the car etc. Still no cable spinning.

Any ideas?

Re: Speedo not working

Posted: 28 May 2017 20:33
by Monkeyzak
Took off the gearbox end of the cable and reseated. Shoved a little more of the cable into the hole on the gearbox. Now it spins at the dashboard end. It didn't before. So that's good

How do I know how much of the cable should be exposed at the dashboard side? Should it be flush? Its not picking up anything that end so maybe not enough cable going into the speedo? Also is it a snap fit? It just slides on and off with no resistance.

Thanks again​

Re: Speedo not working

Posted: 29 May 2017 17:12
by saabfast
Mine is a sort of snap fit but it takes a bit of fiddling to get it pushed on right for it to 'lock' on. Not sure how much was sticking out as I was putting it on by grope from under the dash.

Re: Speedo not working

Posted: 29 May 2017 17:23
by busheytrader
busheytrader wrote:?........The correct one fitted first time with a proper "click" at the back of the dashboard with minimal pushing and pulling.............


IIRC the inner cable was no longer than the outer.

Re: Speedo not working

Posted: 29 May 2017 21:02
by Monkeyzak
I think I may have solved this. A mate fed it into the box. Neither of us checked if the core was spinning before attaching it to the speedo. Silly mistake.

When I took it back out it wasn't. Not enough cable was pushed in to the gearbox. The cable isn't snapping into place on the speedo now. I reckon a wee retaining clip has snapped off. I held it on tight tonight. Jacked up a wheel and the speedo worked but very jumpy. I'll get a new cable. Fit it at the gearbox. Check it!!! Then fit behind the dashboard. Spray the back of the speedo with wd40 as suggested.

Another small problem solved. Should I spray wd40 at the gearbox end?

I am on a very steep learning curve. Every simple job I attempt is never straight forward and most of you guys do in minutes, I take a week ....but I am learning new skills and seeing an old car that's been laid up for most of its life be resurrected!! Looking forward to driving it soon

Re: Speedo not working

Posted: 29 May 2017 21:29
by Monkeyzak
I definitely don't have the extra plastic bit on the end

Hopefully sorted as soon as I get another cable

Re: Speedo not working

Posted: 30 May 2017 12:53
by dmtrmp6
A word of caution,

It is generally not recommended to use a liquid lubricant on speedo drive cables as the liquid lubricant tends to migrate along the cable towards/into the instrument head or can combine with accumulated dust in the cable assembly forming a gel like substance, often the cause of a speedo that jumps or flickers in operation.

Recommended lubrication for a used cable is to remove the inner, clean both inner cable and inside of the outer sheath thoroughly with solvent or similar. When dry apply a small amount of dry powder lubricant only, ie. graphite, Dri-Lube, lock-eze etc.

Similarly, the application of a liquid lube to the cable entry point on back of speedo can lead to migration of the lubricant into the speedo which becomes a magnet for dust.

For a new cable it should not be necessary to add lubricant. Rgds, DM