Strange Speedometer Behavior
Thread Starter
Burning Brakes
Joined: May 2004
Posts: 782
Likes: 27
From: Bend OR
Strange Speedometer Behavior
If I tighten down the cable ferrule nut on the back of the meter, the needle will act normally until I exceed 40 mph. It then hangs there and remains there even when the car is stopped. At some future time, when parked, it seems to let go and drop back to zero on its' own. If I leave the nut loose, the speedo will act normally up to 59-60 whereupon is stops moving higher regardless of speed, but will return to zero on it's own as I slow through 60.
This is the only operational flaw in the car and is making me nuts. Ideas?
This is the only operational flaw in the car and is making me nuts. Ideas?
Melting Slicks
Joined: Jun 2012
Posts: 3,115
Likes: 196
From: Wilton Ca.
If I tighten down the cable ferrule nut on the back of the meter, the needle will act normally until I exceed 40 mph. It then hangs there and remains there even when the car is stopped. At some future time, when parked, it seems to let go and drop back to zero on its' own. If I leave the nut loose, the speedo will act normally up to 59-60 whereupon is stops moving higher regardless of speed, but will return to zero on it's own as I slow through 60.
This is the only operational flaw in the car and is making me nuts. Ideas?
This is the only operational flaw in the car and is making me nuts. Ideas?
After having my Speedo recalibrated I was having the exact same issue so I drove over to the rebuild shop and asked the guy what was going on. He tested the unit while in the car and said it was working ok. He said sometimes the nut needs to be backed off a little or the cable tends to bind in the Speedo housing. He loosened it about a 1/2 turn and said I may need to loosen it a bit more but NOT too much, just a little at a time. It worked ok for awhile then did it again so I loosened the nut about 1/4 turn and pulled on the housing at the firewall grommet. It's been working ok since. Hope that helps.
Gary
Thread Starter
Burning Brakes
Joined: May 2004
Posts: 782
Likes: 27
From: Bend OR
Thanks's Gary, That's kinda' what I'm finding. Thought there might be "a secret". Had it originally re-furbed by Roger Scott and he's the one that suggested loosening it, but had no answer for it stopping at 60.
I think I'll try a different cable. Is there a "preferred" vendor for them? All the usual suspects offer them, but I wonder if one particular one is "least bad".
Gee, Frankie, one might infer 66 from the Avatar photo.......
I think I'll try a different cable. Is there a "preferred" vendor for them? All the usual suspects offer them, but I wonder if one particular one is "least bad".
Gee, Frankie, one might infer 66 from the Avatar photo.......
Melting Slicks
Joined: Jun 2012
Posts: 3,115
Likes: 196
From: Wilton Ca.
IGO200
Unless you think yours is bad, before buying a new cable try loosening the nut, then pull on the housing behind the Speedo , (I used a very large pair of hemostats) then pull on the other side of the firewall, and then securing it somehow to be sure it doesn't slip back up. Even though the nut is loose the housing will slip back up and cause the binding. I used a couple of wire ties just under the passenger side where the cable routes down toward the transmission. I had to fiddle with it a few a few times but finally found the sweet spot and its been fine since.
Gary
Unless you think yours is bad, before buying a new cable try loosening the nut, then pull on the housing behind the Speedo , (I used a very large pair of hemostats) then pull on the other side of the firewall, and then securing it somehow to be sure it doesn't slip back up. Even though the nut is loose the housing will slip back up and cause the binding. I used a couple of wire ties just under the passenger side where the cable routes down toward the transmission. I had to fiddle with it a few a few times but finally found the sweet spot and its been fine since.
Gary
Last edited by Gary's '66; Jul 5, 2014 at 04:08 PM.
Melting Slicks
Joined: Jun 2012
Posts: 3,115
Likes: 196
From: Wilton Ca.
I THINK we're on the same page. Pull the housing toward the firewall, AWAY from the Speedo. Just loosening the nut helped, but didn't cure the problem. The housing had be backed off also and remain that way, hence the wire ties.
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Thread Starter
Burning Brakes
Joined: May 2004
Posts: 782
Likes: 27
From: Bend OR
Safety Car
Joined: Nov 2007
Posts: 4,490
Likes: 808
From: East Central Florida
....and be careful with the repro cables. Had a recent '60 with rebuilt speedo. When the nut is finger tight it locked up the speedo. The repro cable tip had to be ground off a bit as it was too long. I suspect the main shafts out there today may be shallower than originals.
If when the speedo was rebuilt he had to replace and use a repro main shaft, it's inside depth may be a bit shallower, causing your bind-up condition.
You may want to talk to the rebuilder and have him take some measurements of originals vs the repros he has in his shop. If so, grind a bit of the cable tip and you may be all set.
Rich
If when the speedo was rebuilt he had to replace and use a repro main shaft, it's inside depth may be a bit shallower, causing your bind-up condition.
You may want to talk to the rebuilder and have him take some measurements of originals vs the repros he has in his shop. If so, grind a bit of the cable tip and you may be all set.
Rich
Thread Starter
Burning Brakes
Joined: May 2004
Posts: 782
Likes: 27
From: Bend OR
I'm still trying to figure this out. I have 1300 miles on the car now and I have't figured it out.
If I tighten the cable ferrule at the speedo the needle will act normally up to 30 mph.
If I loosen the ferrule way off, the needle will go up to 60 or so normally but then on the way back down it sticks at the same 30 mph. Ilf I wiggle the cable from underneath it will drop down. Can find a happy spot.
Does anyone know what the correct length of the inner cable is ????
EVERYTHING works perfectly except for that. Making me crazy.
Got the NCRS NW regional in my back yard this summer and I'm entering the judging.
If I tighten the cable ferrule at the speedo the needle will act normally up to 30 mph.
If I loosen the ferrule way off, the needle will go up to 60 or so normally but then on the way back down it sticks at the same 30 mph. Ilf I wiggle the cable from underneath it will drop down. Can find a happy spot.
Does anyone know what the correct length of the inner cable is ????
EVERYTHING works perfectly except for that. Making me crazy.
Got the NCRS NW regional in my back yard this summer and I'm entering the judging.
Team Owner
Joined: Oct 2000
Posts: 38,897
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From: Washington Michigan
Race Director
Joined: Jan 2003
Posts: 17,659
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From: Central Arkansas
Not easy to do with the dash installed but you can measure the depth of the socket in the back of the speedometer that the cable end slips into. And then bottom your cable all the way towards the transmission and measure how far the cable tip protrudes from the back inside of the cable ferrule. I would think considering the length of the cable that at least 1/8 inch clearance would be desired. I have another car with a 90 deg adaptor on the back of the speedometer and I have to use small washers inside to space it out enough from the speedometer to prevent to drive into the back of the speedo from being bound up.
Melting Slicks
Joined: Apr 2005
Posts: 2,777
Likes: 105
One fix that I have seen is simply put a cable tie around the cable slightly behind the speedo and then anchor it to something near so that it gently positions the gauge a bit downward. You won't notice it. it's the same as when the needle doesn't drop and you get your hand behind the dash and gently push the cable down a bit and the needle drops and remains working.
What year is your car? Do you have the speed warning buzzer in you speedo?
I ask because the clear lenses on the speed warning option is more concave towards the needle. The needles are different than used with the regular speedos. If you push the lens in while cleaning the needle sometimes the center of the needle binds on the lens. Mine has the speed warning buzzer. It works but I can't hear it unless I roll up the windows.
What year is your car? Do you have the speed warning buzzer in you speedo?
I ask because the clear lenses on the speed warning option is more concave towards the needle. The needles are different than used with the regular speedos. If you push the lens in while cleaning the needle sometimes the center of the needle binds on the lens. Mine has the speed warning buzzer. It works but I can't hear it unless I roll up the windows.
Last edited by babbah; Apr 10, 2016 at 08:49 PM.
Thread Starter
Burning Brakes
Joined: May 2004
Posts: 782
Likes: 27
From: Bend OR
Fixed!
Well shame on me, I fell into the old "It's a new part from -(Paragon)- it must be right" trap. I had an old cable and pulled the inner out of it and compared it to the "reproduction" cable. The speedo end of the inner drive cable was .300" too long on the new one. Trimmed it, and the speedo works perfectly.