Tools You'll Need:
* New speedometer cable: Make absolutely sure you get the correct cable for your year and model. A wrong length will make this job much harder or impossible.
* Socket set and wrenches: Various sizes will be needed, depending on the specific fasteners on your car.
* Screwdrivers: Phillips and flathead, likely.
* Pliers: Needle-nose pliers might be helpful for accessing certain fasteners.
* Shop rags or paper towels: To keep things clean.
* Penetrating oil (like PB Blaster): This will help loosen any stubborn fasteners. Apply liberally and let it sit for a while before attempting to remove anything.
* Torque wrench (optional but recommended): To ensure you don't overtighten anything.
Steps:
1. Disconnect the Battery: This is crucial to prevent accidental shorts or damage to your electrical system.
2. Locate the Speedometer Cable: The cable runs from the transmission to the speedometer in the instrument cluster. Trace the cable from the transmission. You'll need to access both ends.
3. Transmission End:
* Locate the cable connection on the transmission: It's usually a square or rectangular fitting, often secured with a nut or clip. Apply penetrating oil if needed.
* Carefully disconnect the cable: You might need to use pliers to help grip the fitting and unscrew/remove the retaining nut or clip. Take note of how it's connected – it's important for proper reassembly.
* Remove the old cable: Gently pull the cable from the transmission. It may be stiff, so be patient and don't force it.
4. Instrument Cluster End:
* Access the instrument cluster: You'll likely need to remove the bezel around the gauges to gain access to the speedometer cable. Consult a repair manual for your specific model.
* Disconnect the cable from the speedometer: This usually involves a small retaining clip or nut on the back of the speedometer. Again, penetrating oil may be helpful.
* Remove the old cable: Carefully pull the cable out from the instrument cluster.
5. Installation of the New Cable:
* Install the new cable at the transmission: Insert the new cable into the transmission fitting, ensuring it's seated correctly. Reattach the nut or clip securely.
* Route the cable: Carefully feed the new cable through the same path as the old cable. Ensure it's not kinked or strained.
* Connect the cable to the speedometer: Insert the other end of the new cable into the speedometer fitting. Secure it with the clip or nut.
6. Reassemble the Instrument Cluster and Other Components: Carefully put everything back together, ensuring all screws and fasteners are secure.
7. Reconnect the Battery:
8. Test the Speedometer: Start the car and check that the speedometer is working correctly. Drive at various speeds to ensure accurate readings.
Important Considerations:
* Repair Manual: A factory service manual for your 1973 Ford Mustang Mach 1 is highly recommended. It provides detailed diagrams and instructions specific to your vehicle.
* Lubrication: Lightly lubricate the cable ends with a suitable lubricant before installing. This will help ensure smooth operation.
* Patience: This is not a rushed job. Take your time to avoid damaging any parts.
If you're uncomfortable working on your car yourself, it's always best to seek professional help from a qualified mechanic. They have the experience and tools to do the job correctly and efficiently.
