Question about inaccurate speedometer

[Highway_101]

Hello all,

I am having trouble with the speedometer/odometer in my daily driver....a 1984 Riviera. The needle sometimes doesn't register at all, sometimes bounces all over the place, and usually bounces with about a 10 mph sweep. Even when it settles down to the 10 mph sweep, it is still about 10 mph off. Also the odometer isn't registering as many miles as it should. The car has only 67,XXX original miles (or so I was led to believe). So what do you think? Bad cable? Bad speedo? What would you try first? Thanks in advance!

[Guest Dynaflo2]

Michael,

I had a similar problem with my '78 Olds Cutlass. I disconnected the speedo cable behind the dash, lubbed it up, and it was OK, at least for a while. It was about 20 years ago, so I don't remember what I used as a lubricant. White lithium grease perhaps? Don't quote me on that one. I am not certain, but I might have ended up replacing the cable to fix the problem permanently. In any event, the problem in my case was in the cable. I hope this helps.

[NTX5467]

I concur that it does sound like a cable issue. Replacing the cable/housing assembly might be the best long term fix. It might also be that the plastic bushing in the back of the speedometer head is having some wear issues too. In that case, the speedometer head will have to be repaired to fix the problem, but you might hear a bell-type scraping noise when one part of the "speed cup" touches the other part of the speed cup on each revolution. Might be a combination of both things too.

ACDelco has a special speedometer lube. It's pretty jelly-like and probably lighter weight than the white lithium lube mentioned, but at this stage of the game, anything's better than nothing, I suspect, and might help isolate the problem area in the process.

Just some thoughts,

NTX5467

[Highway_101]

Thanks Guys,

I bought a product called "Sil-Glide" made by "AGS". It specifies that it can be used on speedometer cables. I'll try that first. If it is the speedometer head, where can you get them repaired? I suppose I could probably find a used one, but since the car has such low original miles, I hate to change the odometer.

Thanks,

[Guest scott mich bca # 6619]

I would try lubing the speedo cable first. You may have to take the entire cable out to lube it. Take the whole thing out of the car, and then remove the inner cable. That is what has to be lubricated. They sell speedo lube in auto part stores.

It is less expensive to replace the entire cable if that does not fix the problem.

The next step would be either to find a good used one, or send youes off to a speedo. repair shop.

I saw on advertised in Old Cars Weekly called "Bob's Speedometer", located in Grand Rapids, MI. Somebody also recommedned them to me as I am having the same problem in my '55, and will send mine off to be rebuilt this winter.

Scott Mich BCA # 6619, OCA # 3947