1964 full size Buick speedometer cable replacement and speedometer repair

Many cars from the 60s suffered from bouncy speedometers. The 64 Buicks were not immune. They used a unique design, in which the speedometer cable drove a magnetic cup which then pulled the speedometer needle around the curve. Follow my journey of diagnosing this issue and the eventual repair.

Here is the bouncing speedometer in my 64 Wildcat. While bouncing, the car does not count off miles.The speed of the car was kept near constant, but yet the speedometer gave a range of speeds of which to choose from:

The first probable cause for a bouncing speedometer is a binding, worn out, or damaged speedometer cable. I chose to replace mine. To start, remove the left access panel under the instrument panel. In the picture below, the cable is already removed. It went where the threaded ring is. The cable goes through the firewall to the right of the fuse box.

Here is the speedo cable hole from the engine compartment side. It is to the right of the brake booster. I ended up busting my grommet. 45+ year old rubber will not bend well.

The cable comes from the firewall and then goes through a clip to the right of the steering column. It simply pulls out of the clip. Once it is out of the clip, the last place to disconnect it is on the transmission. It is on the driver's side. It simply unscrews.

Ensure the threads are clean and no transmission fluid is leaking out of the connector. I believe at least the cable housing was original to the car. The gold part is the actual speedometer cable that fits in the casing.

I purchased a new speedometer cable from Classic Buicks. It cost me $28 after shipping. I was a little disappointed, because this is a universal part, and was not cut to the same lenght as the one that came out of the car. It was about 5 inches too long. I used it nonetheless.

To the left below are the aftermarket and factory cable casings. As you can see, the factory casing end is formed onto the casing, whereas the aftermarket casing is cut and crimped. The new cable comes with lubricant, which should be spread over the cable and worked around as it is inserted in the casing.

To the left below, the lubricant is applied. To the right, the lubricant after it is worked around. You want the cable well lubricated, but not excessively lubricated. Excess lubricant is wiped off with a paper towel.

Below is the new cable hooked to the speedometer and transmission.

After replacing my speedometer cable, I found that I still had a bouncy speedometer. After hours of troubleshooting with my original and parts car speedometer, I found that a simple lack of lubrication was causing the bouncy speedometer. Below is how I brought my speedometer back to good as new.

First, start by removing the black plastic knob and metal nut from the trip reset knob if you have one. It is not necessary to remove the cable from the back of the speedometer, and I found it to be a pain to attempt. If you have a speedminder or cruise control knob on your speedometer, you will need to disconnect the connector. It is a blue connector that can be disconnected by pushing a screwdriver into where each side hooks. Next, on the actual speedometer casing, remove the silver speedminder or cruise control knob. Then, remove the black set screw at the bottom of the speedometer bezel. It will then lift away.

Remove the three more recessed screws. Next, pull the entire speedometer head out of the dash. It is shown below.

An easy way to test if the speedometer is the problem is with a portable drill. I found the speedometer connector would chuck right up in the drill. It is a very slow task to accrue mileage like this, so I would image stories of odometer rolling back via going past 100,000 miles with a drill are a little exaggerated. By the way, my Buick is mileage exempt.

Once I removed the speedometer head, I found dried lubricant in three places on the gears. Spraying small amounts of white lithium grease in the three places below was all I needed for a smooth speedometer.

Here is the speedometer after being properly lubricated. It is smooth as it has ever been!