speedometer not working
Thread Starter
Le Mans Master
Joined: Feb 2004
Posts: 7,346
Likes: 867
From: Norcal CA
2018 C1 of Year Finalist
speedometer not working
I took the cable off and it works if I spin a drill in reverse. I assume that's the direction it needs to go. Is that the case? I ordered a new plastic speedometer gear for the muncie. I think it has a speedometer reducer drive on it. Not sure why???
Last edited by jimh_1962; Dec 19, 2022 at 11:32 AM.
Burning Brakes
Joined: Jan 2003
Posts: 961
Likes: 275
From: Frederick MD
First and foremost if the cable is newish make sure the square drive is engaging both the transmission and speedo. On my brother’s 68 we found that the cable sheath was too long/square drive too short and it wasn’t engaging properly. We were able to push the ferel on deeper but placing the cable up against the face of a vise and pushing like a SOB. Only needed like 1/2” to properly engage.
if everything is OE GM then as you suggested the transmission gear might be messed up or worst case the speedo itself needs rebuilt.
if everything is OE GM then as you suggested the transmission gear might be messed up or worst case the speedo itself needs rebuilt.
Thread Starter
Le Mans Master
Joined: Feb 2004
Posts: 7,346
Likes: 867
From: Norcal CA
2018 C1 of Year Finalist
First and foremost if the cable is newish make sure the square drive is engaging both the transmission and speedo. On my brother’s 68 we found that the cable sheath was too long/square drive too short and it wasn’t engaging properly. We were able to push the ferel on deeper but placing the cable up against the face of a vise and pushing like a SOB. Only needed like 1/2” to properly engage.
if everything is OE GM then as you suggested the transmission gear might be messed up or worst case the speedo itself needs rebuilt.
if everything is OE GM then as you suggested the transmission gear might be messed up or worst case the speedo itself needs rebuilt.
1967 Pedal Car Champion
Joined: Mar 2020
Posts: 8,893
Likes: 4,074
From: US-PNW
So the speedo works with a drill on the cable? If so, that's a good thing given the effort to remove the speedo. Have you pulled the trans speedo gear yet to inspect for sheared teeth? If they're all there, you could have a bad drive gear inside the trans.
Le Mans Master
Joined: Aug 2017
Posts: 8,336
Likes: 2,809
From: Cool Northern Michigan
jimh,
On several model years the end of the speedometer cable that goes into the tranny has a plastic tip insert. It is more or less a shear-pin or a sacrificial part designed to snap off. The idea being that its better / easier / cheaper to replace that tip than the trans gears or the speedometer unit itself.
With the bullet removed from the tranny, shine a light inside and see if the plastic tip is broken off inside the "driven" gear.
Lots of cables fail from lack of lubrication. However, oil is the worst thing to use. The design of the cable is a spiral and can "wick" or auger oil uphill to the back of the speedometer ruining the unit. Always use a light grease that can handle heat, such as gun grease inside the cables' housing.
If you have any type of adaptor / reducer, you can bet that someone changed the axle ratio.
On several model years the end of the speedometer cable that goes into the tranny has a plastic tip insert. It is more or less a shear-pin or a sacrificial part designed to snap off. The idea being that its better / easier / cheaper to replace that tip than the trans gears or the speedometer unit itself.
With the bullet removed from the tranny, shine a light inside and see if the plastic tip is broken off inside the "driven" gear.
Lots of cables fail from lack of lubrication. However, oil is the worst thing to use. The design of the cable is a spiral and can "wick" or auger oil uphill to the back of the speedometer ruining the unit. Always use a light grease that can handle heat, such as gun grease inside the cables' housing.
If you have any type of adaptor / reducer, you can bet that someone changed the axle ratio.
1967 Pedal Car Champion
Joined: Mar 2020
Posts: 8,893
Likes: 4,074
From: US-PNW
The speedo cable, whether cold or hot, is always rotating if the transmission gears are turning (forward at least - never checked in reverse). The cable is gear driven at the trans, so it can't bind due to temperature without damaging the plastic gear and becoming inoperable. Sounds like some excess lube may have worked its way up the cable and the speedometer head is getting impeded by it due to viscosity/dirt/both. My '67's speedo had a small puddle of lube in the head and would bounce. Once wiped out it worked great – unfortunately that requires pulling the dash and speedo out to get to the inner works. Speedometer heads are like mechanical clockworks in the lube department: a minuscule amount is all that's required.
Thread Starter
Le Mans Master
Joined: Feb 2004
Posts: 7,346
Likes: 867
From: Norcal CA
2018 C1 of Year Finalist
I have not had time to pull the speedo gear out. I asked my buddy who owns a speedshop to order one for 3.55 gears. We are waiting on the part before I start tearing it down. Its not that big of a deal. I have a GPS he can use to check his speed if needed. To tell you the truth I never really look at my speedometer. I can tell how fast just by the revs of the engine and which gear I am in. Sometimes, I will look at the tachometer. But for a new driver it will be important for the speedometer to work.
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Thread Starter
Le Mans Master
Joined: Feb 2004
Posts: 7,346
Likes: 867
From: Norcal CA
2018 C1 of Year Finalist
jimh,
On several model years the end of the speedometer cable that goes into the tranny has a plastic tip insert. It is more or less a shear-pin or a sacrificial part designed to snap off. The idea being that its better / easier / cheaper to replace that tip than the trans gears or the speedometer unit itself.
With the bullet removed from the tranny, shine a light inside and see if the plastic tip is broken off inside the "driven" gear.
Lots of cables fail from lack of lubrication. However, oil is the worst thing to use. The design of the cable is a spiral and can "wick" or auger oil uphill to the back of the speedometer ruining the unit. Always use a light grease that can handle heat, such as gun grease inside the cables' housing.
If you have any type of adaptor / reducer, you can bet that someone changed the axle ratio.
On several model years the end of the speedometer cable that goes into the tranny has a plastic tip insert. It is more or less a shear-pin or a sacrificial part designed to snap off. The idea being that its better / easier / cheaper to replace that tip than the trans gears or the speedometer unit itself.
With the bullet removed from the tranny, shine a light inside and see if the plastic tip is broken off inside the "driven" gear.
Lots of cables fail from lack of lubrication. However, oil is the worst thing to use. The design of the cable is a spiral and can "wick" or auger oil uphill to the back of the speedometer ruining the unit. Always use a light grease that can handle heat, such as gun grease inside the cables' housing.
If you have any type of adaptor / reducer, you can bet that someone changed the axle ratio.
Thread Starter
Le Mans Master
Joined: Feb 2004
Posts: 7,346
Likes: 867
From: Norcal CA
2018 C1 of Year Finalist
The speedo cable, whether cold or hot, is always rotating if the transmission gears are turning (forward at least - never checked in reverse). The cable is gear driven at the trans, so it can't bind due to temperature without damaging the plastic gear and becoming inoperable. Sounds like some excess lube may have worked its way up the cable and the speedometer head is getting impeded by it due to viscosity/dirt/both. My '67's speedo had a small puddle of lube in the head and would bounce. Once wiped out it worked great – unfortunately that requires pulling the dash and speedo out to get to the inner works. Speedometer heads are like mechanical clockworks in the lube department: a minuscule amount is all that's required.
6th Gear
Joined: Jan 2005
Posts: 6
Likes: 0
From: Texas
New to the C1 world. Just got a '59.
The speedometer & odometer don't work as a few other things I need to address(clutch is really high).
It does bounce a little while driving, but still lays over on the left side never actually coming up to a speed.
I was going to check the cable first and this thread really helps as I have no idea what I'm doing.
Hopefully something simple, but will pull cluster if need to.
The speedometer & odometer don't work as a few other things I need to address(clutch is really high).
It does bounce a little while driving, but still lays over on the left side never actually coming up to a speed.
I was going to check the cable first and this thread really helps as I have no idea what I'm doing.
Hopefully something simple, but will pull cluster if need to.
Le Mans Master
Joined: Aug 2017
Posts: 8,336
Likes: 2,809
From: Cool Northern Michigan
Well, first you are in the wrong section.
Second, you are responding (high-jacking) to an old thread.
If and when someone responds, are they talking to you or some posts from yrs ago?
You say you don't know what you are doing?
That makes around 10,234 of us.
Its ok. Comes with time.
Always open a new thread with your question.
Always give model yr.
And good luck.
Second, you are responding (high-jacking) to an old thread.
If and when someone responds, are they talking to you or some posts from yrs ago?
You say you don't know what you are doing?
That makes around 10,234 of us.
Its ok. Comes with time.
Always open a new thread with your question.
Always give model yr.
And good luck.
Last edited by HeadsU.P.; Jul 30, 2025 at 09:04 PM.
