If your speedometer stops working, it’s probably a broken cable. But before you start taking things apart, check to see if the odometer is still working. If it is, the cable is OK and the problem is with the speedo instrument itself. If you have a local instrument specialist, repair may be possible, but replacement is usually easier. If neither the speedometer nor odometer work then proceed to replace the cable as follows.
In order to remove the old cable, it is necessary to remove the instrument panel. To avoid accidents with the mass of electrics behind the panel, the first step is to disconnect the battery. Now remove the instrument panel. On 2CVs with small speedos there are 4 crosshead screws on the face of the panel. On cars with the larger speedo, the screws are on either side of the panel.
Once free, carefully pull the panel towards you until you have enough room to get your hand behind the panel. Take care not to disconnect any wires. Unscrew the plastic sleeve which holds the cable to the back of the speedo. You can now confirm whether the cable is your problem. Hold the squared end of the inner cable. If the cable is broken you will be able to withdraw the inner cable from the outer.
Working under the parcel shelf, find and remove the rubber grommet where the speedo cable passes through the shelf to the back of the instrument panel. The grommet also carries the wiring for the brake light switch. The end of the cable can now be pulled through the hole (with a bit of juggling) and then pulled through the grommet, taking care not to damage the insulation of the brake light wiring.
Inside the engine compartment, find the speedometer cable where it comes through the bulkhead, adjacent to where the nearside heater tubing is split between screen and feet. It’s easier if you remove the top cardboard tube between the metal junction on the bulkhead and the screen. Follow the cable down to where it enters the back of the gearbox and look for an 11mm bolt, screwed into the gearbox just below the cable. This may be difficult to see because of the handbrake linkage and it’s likely to be smothered in grease and oil which should be cleaned off with a rag.
Unscrew the bolt with a ring spanner or, if there is room, a socket. Once the bolt is free, the cable can be pulled out of the gearbox.
Working under the parcel shelf again, pull the cable from the engine compartment into the car. You will need to pull the foam sleeve out of the hole in the bulkhead first. The sleeve is split so that you can remove it from the cable easily for use on the new cable.
Before fitting the new cable, check to see that the speedo hasn’t seized up, which would have caused the cable to break in the first place. Gently push a small screwdriver, about the same size as the squared end of the inner cable, into the back of the instrument. Rotate it in the same direction as the hand on the speedo would go and check the hand moves. If it does, proceed to fit the new cable, but if you can’t get a flicker from the hand or you can’t turn the screwdriver at all, it is likely that you need a new speedometer. If in doubt, don’t fit the new cable since it will break immediately the car moves if the speedo is seized.
To fit the new cable, start inside the car by pushing the gearbox end of the cable through the hole in the bulkhead, remembering to replace the foam sleeve. Locate the cable into the gearbox. If it won’t go in, try turning the inner cable a fraction at a time until it locates in the drive properly.
Replace the 11mm bolt. If you can’t get it started in the thread, you may have pushed the cable into the gearbox a fraction too far, or not quite far enough. If you study the old cable you will see that the bolt holds the cable in place by passing through the narrowed part of the metal sleeve on the end of the cable. By pulling or pushing the cable 1mm at a time you should be able to feel the bolt pass the sleeve into the thread and get it started. Tighten the bolt and ensure the cable is secure.
Inside the car, push the cable through the rubber grommet and then push the cable through the hole in the parcel shelf just far enough to reach the back of the speedo. Locate the squared end of the inner cable into the drive at the back of the speedo until the metal sleeve is a snug fit against the instrument and then screw on the plastic sleeve. Remember to relocate the rubber grommet properly in the hole above but ensure that you haven’t disconnected any wires.
All that remains is to ensure that the new cable doesn’t have any unduly tight bends or kinks throughout its run. This will result in clicking noises from the speedo when driving along, or the speedo hand may be erratic. If this does happen it can usually be cured by slight adjustment to the route the cable takes so that bends are as smooth as possible. Also, ensure that it is routed well away from sources of heat or other parts of the car which have to move, such as the handbrake linkage and heater controls. Reconnect the battery and heater tube. Time to go for a test drive!
