Speedometer Replacement

Until the introduction of electronic instrumentation, most auto speedometers were cable driven. The drive cable has a square end and threaded bezel that simply inserts into a fitting in the back of the speedo and then travels directly to the transmission. After years of use, the square end of the cable occasionally rounds out and the cable spins noisily in the speedometer housing. Needless to say the needle just moves in a jerky, bouncing fashion. To replace the speedo the instrument cluster must come out of the vehicle.

Removing Screw
To remove the cluster you must remove the four screws securing the cluster housing, two 3/8-inch nuts at the back of the cluster base and remove the lower fascia and U-shaped bracket under the steering column. Then disconnect the gear selector wire if your car is automatic. Reach up under the back of the dash and remove the instrument panel lights and two connections each at the back of the temperature and fuel gauges. Obtaining a reproduction assembly manual would be helpful as all the wiring colors and connections are called out in the electrical schematic. Use care when removing the Phillips head screws so you don't scratch the paint on the cluster housing.

Cluster Removal
Once all the retainers are removed and the light sockets pulled free, the housing will come out. To facilitate removal, slightly pull the cluster forward and then tilt it down at the top so it will come out with the gauge faces turned down toward the floor. The forward lip of the housing tucks under the steering wheel bezel so as you are pulling the top of the housing down, push back the bottom at the same time. Again, use care not to scratch the paint. Remove the cluster slowly and if you feel any resistance, double check the light connections, etc. to make sure you disconnected them all.

Replacement
A far as we know there is no aftermarket supplier for reproduction 1957 speedometers. Most 1955-'57 parts suppliers will rebuild your original or send you a finished unit with your original sent back as a rebuildable core. Notice the odometer reading on this rebuilt unit reads 0 miles. If your original mileage is important to you, then you must send your speedo in to a rebuilder and wait until they can turn it around. Since the mileage on our original was not correct anyway, we chose the fastest method and took an off-the-shelf rebuild. A little graphite powder in the cable housing helps to lubricate the movement.

Unit On Bench
A clean work area is a good idea, and at the same time you install the rebuilt speedo you can detail out the other components. A little plastic polish will clean up the gauge lenses and the housing can be treated to a thorough cleaning. The speedometer is secured by four screws and easily removed. Obviously, all the parts will be replaced the same way you removed them, but we still like to lay them out in the order of removal and keep everything in separate areas. If your gauge housing is dinged or scratched, now is the time to do some repainting. Once you've reassembled the cluster, the reinstallation is simply the reverse of the way you removed it. From start to finish allow about two hours. No special tools are required. It's a rewarding project and one that will obviously keep you cruisin' at the required speed limit!