1977 speedometer problems
I am presently working on a 77 coupe for a friend. The complaint is the speedometer is sluggish, and the needle bounces a little. I disconnected the cable from the back of the speedo, and spun the bearing by hand. It spun fine with no sticking or bouncing. I disconnected the cable from the transmission and spun it by hand. It seems a little stiff, but turns. The car has cruise, and the 2 piece cable. How can I determine where the problem is? Could the cruise control where the cables attach be at fault? If so, who repairs those? I would appreciate some help. Thank, Mark
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Re: 1977 speedometer problems
Seems I had this problem with my 78 years ago and did two things which corrected it. Went on several road trips and speedometer worked as one would expect it to. I lubricated the cable, both cables with a graphite lubricant. I also had the transducer rebuilt which I suspect was the primary problem. Transducers, (they control cruise control), have a big, tightly wound spring that rusts up. If you open the cover of the transducer, you could launch the spring along with rust dust. The transducer is located under the driver's side front fender just north of the alarm horn. Your friend's 77 would have a similar configuration. I had mine rebuilt out of someplace in Wisconsin but they failed to rebuild it...I did not get the original back along with its stickers and broadcast codes. No big deal but that's what I expected. So, the Driveline has individuals claim they can rebuild them.
Hope this helps.Tom Russo
78 SA NCRS 5 Star Bowtie78 Pace Car L82 M2100 MY/TR/Conv -
Re: 1977 speedometer problems
They can be bought at Corvette supply houses. They are not that expensive and a little iouchy to install and calibrate. However, there is a trouble shoot section in the 1977 service manual under the accessories section. Also, check that the cables are not too long. Of course, if the cables are original to the car the cables being too long would not apply. I had a jumpy speedo when I replaced the upper cable and the fix was to cut-off about 1/8 inch of cable.Comment
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Re: 1977 speedometer problems
Why has it DIESEL written on it? (I assume you are the seller - how much would be shipping to Germany?)
Oh, and what kind of calibration does it need? (Sorry for just asking instead of checking the Service Manual myself.)
And: I once heard to never lube the trans-cables... Wrong or true?Comment
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Re: 1977 speedometer problems
Calibration is a pain. I have tinkered with mine over the years and have yet to get it dialed in. At 65, it wants to surge and drop about 5-6 miles an hour. But than I don't have one of those NOS ones!
If you need the troubleshoot section...I'll send and scan.Tom Russo
78 SA NCRS 5 Star Bowtie78 Pace Car L82 M2100 MY/TR/ConvComment
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Re: 1977 speedometer problems
Thanks for the offer - I should have that... (If not, I'll come back...)
Ah, and now I know, you meant calibration of the cruise control and not the trandsuctor itself. Well, the CC never worked on my '77 since I have it (1992), so I would have to tackle that anyhow - errr, one day - it's not that high on my list of priorities.
Then again (thinking about your offer another time) if it would not be much hassle for you, of course I would very much appreciate your scan.........
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Re: 1977 speedometer problems
Oliver-----
I am NOT the seller; I do not sell parts. I have no idea who the seller is.
I don't know why the label with "diesel" is seen on this part. It's possible that it was also used for some diesel applications. However, I can tell you that the part number is applicable to 1977 Corvette.In Appreciation of John HinckleyComment
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Re: 1977 speedometer problems
Oh - okay, thanks for the clarification.Comment
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