Replacing Speedo Inner Cable

[Myrtles Man]

Having decided that a speedo needle that waves back and forth like a conductor's baton is not really conducive to the close observance of speed limits, I've purchased a new inner cable to steady it down a bit. I intend to go at it from the dashboard end, first problem being obtaining access to the knurled nut at the rear of the speedo. A search here tells me that there are two screws, accessible via cunningly-placed holes in the glovebox inner tinware, which are located by feel with a cross-headed screwdriver (Phillips, I imagine - don't think Torx (sp?) was around when moggies were assembled). I've already had a first attempt, with no success, and I'm wondering what sort of size the Phillips head should be; maybe I did actually locate the screw but perhaps the Phillips head was too small to 'bite'; I was wary of digging about in there too insistently as I could envisage myself chewing into the wiring spaghetti that lives behind the dash. Any tips for how to proceed?

[les]

A medium Philips is needed, then it's a matter of location. If you hold the screwdriver quite straight the screws will be around there, once you think you are located gently turn driver to and fro, resistance should confirm you're there,

[ianmack]

While the speedo is out check also the routing of the cable to the gearbox. Tight curves can cause erratic operation. They like a smear of grease too.

[Sleeper]

You may or may not have the securing screws in there , it can stay in place with friction . Use of a torch and mirror will let you know if they're still there and give you an idea of the head size...

John

[Myrtles Man]

Many thanks for the tips gentlemen - I'll get back to you if I run into any further hitches.

[Myrtles Man]

Well, I'm back again, having run into another slight hitch. Following the excellent advice above I removed the speedo from the dashboard and unscrewed the knurled nut holding the end of the drive cable. However, when I tried to pull the inner cable from the outer it wouldn't come out, merely stretching a bit as I pulled but appearing to be locked fast at the gearbox end. Now, before I lock the mole grips on to it and pull like a mad dentist I thought it might be wise to check back with you chaps first. Rightly or wrongly I assumed that the inner would be a mere slot-in fit at the gearbox end (as with cables that I've occasionally replaced on motorbikes) and, indeed, the replacement cable I've bought suggests that this should be the case too as there is nothing attached to that end of the cable, merely a short 'collar' at the speedo end. Am I overlooking something or should I just man up and get on with the serious pulling?

[ianmack]

If you disconnect the cable at the gearbox end as well it might slide out more easily

[simmitc]

I have no argument against replacing just the inner cable, but given that the complete cable (inner + outer) is readily available, quite cheap, and avoids the need to handle the greasy inner bit; why would you not simply fit the complete cable? This would also remove any possibility of a worn liner. Just a thought.

[Myrtles Man]

Again, thanks for your advice and guidance; the reason I opted to attempt to merely replace the inner was to avoid a trip underneath the beast to wrestle with the gearbox end of things if at all possible - it all seemed so simple in theory. Is it then the collective wisdom that my plan was flawed from the start and that the inner is not simply detachable/replaceable from the speedo end?

[simmitc]

The inner cable can get stuck in the drive on the gearbox, so as suggested above, you'll probably need to unscrew the cable from the gearbox in order to swap the inner. The knurled nut on the gearbox should be easy to turn with a pair of pliers. The one thing that you might find a problem with is that on some modern cables, the nut at the speedo end is marginally too large to pass through the bulkhead. Easily solved by filing either the nut or the hole; and just another example of poor quality modern parts. Still, at least the new cables do work.

[Sleeper]

You've nothing to loose getting the mole grips on it and giving it a yank...if that is not successful then a trip down under the car is next in line.

John

[paul 300358]

If you do end up under the car undoing the gearbox end, make sure that the large plastic drive that the cable screws into remains tight in the gearbox casing when undoing the cable with pliers. If not, you will have a oil leak.

[oliver90owner]

Before jumping to any conclusion, I would be checking that the outer is routed properly. Any too-sharp bends could give the symptoms reported.

It may even be a worn outer that is the problem. Might be dried out lubricant, too.

[Myrtles Man]

Thanks again one and all for your very helpful responses. So, my next go at the task will be the deferred attack by mole grips, followed, very likely, by removal of the cable from the gearbox, then either successful completion of inner removal/replacement or, failing that, replacement of the whole cable gubbins, as suggested. I'll let you know how it pans out.

[philthehill]

I will cut to the quick and say that if you cannot get the inner cable out of the outer cable the cable assembly is shot and you need to replace the cable that is both inner and outer.
It may be that the inner cable and/or outer cable has become frayed and that is what is stopping you extracting the inner cable.

When lubricating the cable only lightly lubricate the bottom two thirds of the cable with say 3 in 1 (even though the wksp man says high melting point grease - from experience I find a light lubricant to be better) as you do not want any lubricant to get into the speedo head.

Years ago I used to made up inner cables from long lengths of stock speedo cable and use a speedo cable anvil to get the square on the ends. Happy days.

[Myrtles Man]

Thanks for those thoughts Phil. Must admit, I was proposing to lubricate the lower half of the inner with HMP graphite grease but I will now bow to your infinitely greater experience and use Three-in-One. I hear what you say about the likelihood of the whole cable being shot too. Here goes.

[Myrtles Man]

Job's a good 'un! Old inner removed and new one installed. The old one did take a bit of shifting; I was pulling on it fit to bust and it just wouldn't move. I then decided to try twisting it and pulling at the same time and suddenly it just decided to let go, pulling all the way out easily. Gave the bottom half of the new cable a spot of Three-in-One, as per Philthehill's advice and it slipped in with very little trouble, other than a bit of binding as it was forced to negotiate the two or three changes in angle that the outer takes. Haven't driven it yet but, with any luck, the metronome should have been converted back into a speedo needle. Thanks everyone for your helpful contributions.