Technical Replacing broken speedo cable

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Technical Replacing broken speedo cable

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Oct 17, 2005
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Belfast, County Antrim
Ok, so I've been without a working speedometer for about 3 months now (naturally I've not been driving the car at all, as that would be illegal) -- I had found that the previous cable was snapped at a kink in the gearbox end. I managed to get hold of a new cable from Fiat, with some difficulty, as the ones mentioned in the eper for my model are all discontinued. Luckily, they found another part number covering a cable which the guy said he always used for unos in the past.

So anyway, I finally found some time (and weather) the other week to do all the horribleness of removing the old cable through the grommet and over the heater, then insert the new cable back the same way, dislocating my arm in 3 places to do so. But unfortunately, the cable still isn't turning when I have it attached to the gearbox and I try driving the car forwards and backwards... :(

It seems to be to do with the connection to the gearbox. When I ordered the cable initially (before it emerged it was discontinued) the Fiat guy at Mervyn Stewart suggested that I also get a small "gear" part that fits into the gearbox with the cable - I didn't really know what he meant as I figured it was just a straight cable replacement, but agreed to order it. Then when all the trouble with discontinued parts came about, the gear didn't get ordered anyway, but I was told it should be fine whenever I just collected the replacement cable by itself.

Anyone know about this gear-type thing? My replacement cable has an end which is flattened down into a square, and a sheath which screws down around the outside of the gearbox connector. The sheath thread fits fine, and I have tried pushing the cable down as far as it goes onto the socket before screwing on, but still it won't turn when driving. Unfortunately the socket's so difficult to get to that I can't even make out what size the cavity is inside! Feeling around with an allen key and a pin though it seems to be larger than the square end of the cable...

Anyone know what I'm missing? :confused:
 
Hi Tony

Firstly, I am not sure about the gear thing that fits in the gearbox end of the cable.

I just thought I would share my experience of changing the speedo cable in case it helps. Mine was a '89 MK1 uno FIRE.

The cable basically consists of a metal cable inside a flexible plastic tube which is rotated at the gearbox end. At each end of the cable it should be square in shape. In my car, in order to get the cable to work you must make sure that there is a sufficient amount of the square end at both the gearbox and the clock ends to seat in nicely. What I did was hooked it up at the gearbox end first and pushed the cable in as far as it would go. I then connected up at the clock end and it seemed to work fine. If you pull the cable through too much at the clock end it disconnects from the gearbox and won't work.

It does sound, however, that it is not your cable that is at fault but the fact that the spinning part of the gearbox is not working. Maybe you should try and get hold of this gear part?

Thanks

Phil
 
Hi Tony,

It would be quite a coincidence if you had both a cable problem and a drivegear problem - unless the kinked cable then caused the gear to break.

It sounds to me as though the drivegear has disappeared into the gearbox. I'm not sure about the Uno specifically, but certainly on other FIATs when you remove the cable, you should see the yellowish-white plastic drivegear protruding from the steel sleeve that has the threads for the knurled cable ring to screw on to.

Fortunately the drivegear-sleeve is held into the differential housing by a small Allen-head bolt and is easy to change. If you undo this bolt (on the side of the diff housing, I think it's a 5mm Allen key that fits) the drivegear and its sleeve will pull straight out upwards (may be tight due to rust/O-ring - reattach the old cable to give you something to pull on).

It is possibly easiest to do this from under the car, raised high and supported on axle stands. Be warned that there is nothing to stop the drivegear dropping out as you remove its mounting sleeve, and there is nothing more frustrating than the drivegear sinking silently in the slimy depths of the gearbox... so take care ;)

When you refit the sleeve (with a new drivegear, of course), be very careful to line up the small hole with the locating Allen bolt. If you don't, you will snap the sleeve mounting in the gearbox casing, and the new drivegear will become chewed out through running at an angle. Don't ask how I know this :eek:

While doing a search I just found one of your posts from three years ago, so it's good to see you're still keeping the Uno in fine fettle.

Cheers,
-Alex
 
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Aha! :idea:

Time to update you all on an enlightening week -- many thanks Phil and Alex for your replies, but it seems my problem isn't an especially well-known one. It appears that my model of Uno (perhaps all mk2s, I'm not sure) has a slightly different type of speedo cable to most others.
phil_harry said:
The cable basically consists of a metal cable inside a flexible plastic tube which is rotated at the gearbox end. At each end of the cable it should be square in shape.
Seems you hit the nail on the head there Phil, even without realising -- my cable isn't actually meant to have two square ends (i.e. where the round cable has been flattened off to a square) -- it should be square at the clocks end, but not the other end, where it enters the gearbox. There's actually meant to be a metal "key"-type thing attached:


The cable I bought from Fiat was of the both ends square variety, as it was the only one that they can still stock, but it wasn't working for me. So I took a trip to my local scrappy and found a 1.0 Uno and removed its cable and sheath -- when I removed the cable from the gearbox I found what I thought I'd remembered from the old cable.... Here's a pic of the two cables for comparison (L second-hand and R new):


So the two components concerned here are:
  • 46419961 FLEX/SHAFT - The cable that Fiat still provides, but does not actually work in my Uno. Squared off at both ends.
  • 7729241 FLEX/SHAFT - The cable that's specifically relevant to my model of Uno. Slightly longer than other cable (about 3 inches); squared off at clocks unit end, with ~5mm circular "key" fixed to gearbox end.
The latter is no longer available from Fiat so if you need one, best get looking in those scrapped Unos! The other important thing to note here is that if you want to maintain your speedo cable, you really should take off the gearbox end first to see what type of cable it is -- I think that my trying (and failing) to pull the cable out from the cab end a few months back was what finished off the cable in the first place :eek:

I took a few more pictures while in the process, I'll probably get a brief guide to removing/maintaining the cable put up soon. This, alongside removing and replacing the heater valve last week, has given me some of the most annoying and awkward work I've done on the car yet... :bang: but apart from that at least she's still going fine!
 
Hmm, the particularly annoying thing to note here is that a look in the Eper shows that actually, that cable from the scrap yard could really be any one of a number of part numbers. None of them mention this key thing fitted to the end, or that there is any difference at all to any other cable. The fact that the cable that Fiat found for me (the one that turned out to be incompatible) is also listed as a suitable part, does kind of annoy me a little...

The full listing is as follows:
Code:
7729241  NIPPON-SEIKI                                      01
7736874               GS (M1 ,M2 ,M3 ,M4 ,M5 )             01
7736874               GS +M6                   C0529       01
7736874               GS +M7                   C9010       01
7736875               GS +M7                   D9010       01
7736875               GS +M7                   C0529       01
7751192               GS (M6 ,M7 ,M8 )         D0529 C0857 01
7785023               GS (M6 ,M7 ,M8 )         D0857       01
46419961              GD (M1 ,M3 ,M4 )                     01
46419961              GD (M6 ,M7 )             C0529       01
7760807               GD (M6 ,M7 ,M8 )         D0529 C0857 01
7785022               GD (M6 ,M7 ,M8 )         D0857       01
7736875               M9                                   01

7736864               GS (M3 ,M4 ,M5 )                     01
7736864               GS +M6                   C0529       01
7736868               GD (M3 ,M4 ,M5 )                     01
7736868               GD (M1 )                             01
7736865               GS +M7                   D9010 C0857 01
7785324               GS (M6 ,M7 ,M8 )         D0857       01
7752332               GS (M6 ,M7 ,M8 )         D0529 C0857 01
7785324               GS (M6 ,M7 ,M8 )         D0857       01
7785322               GD (M6 ,M7 ,M8 )         D0857       01
7761527               GD (M6 ,M7 ,M8 )         D0529 C0857 01
7736865               M9                                   01
(In this instance, my car would be an M6)


:eek:


EDIT: anyone want to buy a brand new cable/sheath, #46419961 off me? :cool:
 
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Thank you guys for this topic as my Speedometer stopped working this morning...

How does one go about replacing it?
 
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First check that it is connected well on both ends...

It is the thickest wire (cable actualy) under the dash, if you take the guard above the pedals off you should be able to reach up to te back of the dash and just make sure its pushed in firmly...

It exits the firwall high up on the passenger side through the big grommet along with another cable... follow it and make sure other isde is in securely....
 
now that you guys mentioned it i should start considering changing mine. It was making a spining noise at the speedometre's end, guess it might have not been secured there. Dont think parts over here should be a problem.

Just found it difficult to secure at both ends. So i connected it at the gearbox side first,after numerous attempts (the tricky part) and finaly at speedometers side, worked like a charm.
 
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Yeah speedo side is the easy one, just pull the outer sheeth back, push the connector on solidly, then push the sheeth back down.
 
Your welcome beat, its not a big job just tricky, if you know how to fasten and undo a nut at night without a flash light its as easy as that.
 
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