Speedometer problem...oh, fun!

[patrick66]

Two years ago, I was driving my '66 Coronet, when the speedo needle stuck at 80 mph. The odometer continued to work just fine, and work accurately. Last night, I decided to fix that and replace a few light bulbs in the cluster. Got the cluster out and started to check things over. The needle, which I thought might have hung up on the face of the speedometer, was where it was supposed to be, and not rubbing anywhere that would hang it up at that position. Once I separated the speedo itself from the cover, the needle remained at 80. The whole mechanism felt sticky! Goofy as hell!

I cleaned the connector to the cable with WD40, being careful not to hit the odometer. After letting that air-dry, I turned the connector again to see what would happen. Same sticking needle. Next step was to use 3-in-1 Oil in that little lube hole, plus a tiny drop on the back of the unit. I let that sit overnight. Tonight, I wiped that off again, then checked the cable. All of that looked good. Time to reassemble and reinstall...

Ah, ****. The little bulb holders got misplaced. Time to hunt down new ones, plus get new bulbs and replace all at one time. Found new bulb holders at NAPA. The wrong holders, of course! So much for reinstalling the cluster tonight!

Tomorrow's task is return the new holders to NAPA and get the correct ones, reinstall the cluster and give it a road test! Got a 300-mile drive with the Coronet this Saturday as part of the Hot Rod Hundred, which will be the longest trip the car has been on since 2010, for a film shoot.

More to follow.

 

[eric383]

Great info and good luck with the trip.

 

[patrick66]

Looks like I'm gonna have to send the speedometer out for service this Winter, sometime. Put everything back together with new bulbs, installed the cluster, and...not a bit of difference. The speedo needle popped up to 80 as I started in Drive, and bounced back to 70 this time. My oil pressure light and both turn indicator dash lights quit. I have backlighting, the clock is working, as are the fuel and temp gauges. The odometer works fine, as before.

I believe the spring in the back of the unit, where the odometer is located, either broke or lost tension, somehow. Since the odo is independent of the speedometer function, and it works; I believe this to be the problem.

I have a problem with the AM radio that has been ongoing for many years. The antenna is good, and so is the speaker. There is power to the radio. You can hear the speaker go "boop" when power is turned on. No static or any other noise of any kind when the volume is adjusted. No stations tune in, either.

My ammeter burned up in 2010. Several years ago, I bypassed that altogether and run an underdash voltmeter now. I decided to remove the old ammeter altogether and install a replacement, but then decided to leave the bypass in place. After looking at the back of the original ammeter, I noticed the post was loose, and the contact point at the base of the post was burned completely away. I'll shoot a pic tomorrow and post it. It'll convince you to bypass yours, whether it's still good or not!