f100 1966 speedometer problems
Post Fiend
Joined: Nov 2000
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From: Glendale Arizona
Garbz
Elder User
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From: Glendale, AZ
My '66 speedo works off of spun gears via the cable end. Maybe '67 switched to induction?
Elder User
Joined: Nov 2010
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From: Glendale, AZ
Unlessssss....speedo needle is bent or out of whack and hanging up on gauge face behind it.
Post Fiend
Joined: Nov 2000
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From: Glendale Arizona
There is no direct connection between the speedometer cable and the needle. They all work off of induction to produce a set amount of drag based on RPM of the cable.
There are two wing arms that are attached to the input from the cable. These are very close to and interact with a drum to drive the speedometer needle. There is a return spring also to return the needle as RPM diminishes.
The odometer has a gear set driven directly from the input shaft through the use of jack shafts to drive the larger odometer set gear.
A lagging needle after a certain speed is dirty and hanging up.
A bouncing needle at any speed is indicative of a poorly lubed cable or damage to the driven or drive gear in the transmission.
Garbz
There are two wing arms that are attached to the input from the cable. These are very close to and interact with a drum to drive the speedometer needle. There is a return spring also to return the needle as RPM diminishes.
The odometer has a gear set driven directly from the input shaft through the use of jack shafts to drive the larger odometer set gear.
A lagging needle after a certain speed is dirty and hanging up.
A bouncing needle at any speed is indicative of a poorly lubed cable or damage to the driven or drive gear in the transmission.
Garbz
Elder User
Joined: Nov 2010
Posts: 676
Likes: 0
From: Glendale, AZ
There is no direct connection between the speedometer cable and the needle. They all work off of induction to produce a set amount of drag based on RPM of the cable.
There are two wing arms that are attached to the input from the cable. These are very close to and interact with a drum to drive the speedometer needle. There is a return spring also to return the needle as RPM diminishes.
The odometer has a gear set driven directly from the input shaft through the use of jack shafts to drive the larger odometer set gear.
A lagging needle after a certain speed is dirty and hanging up.
A bouncing needle at any speed is indicative of a poorly lubed cable or damage to the driven or drive gear in the transmission.
Garbz
There are two wing arms that are attached to the input from the cable. These are very close to and interact with a drum to drive the speedometer needle. There is a return spring also to return the needle as RPM diminishes.
The odometer has a gear set driven directly from the input shaft through the use of jack shafts to drive the larger odometer set gear.
A lagging needle after a certain speed is dirty and hanging up.
A bouncing needle at any speed is indicative of a poorly lubed cable or damage to the driven or drive gear in the transmission.
Garbz
Post Fiend
Joined: Nov 2000
Posts: 6,060
Likes: 7
From: Glendale Arizona
LOL, I just happened to have one sitting here on the desk that i was trying to figure out how to convert it to pulse for the uni.
Garbz
Garbz
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Post Fiend
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From: Glendale Arizona
The T45 i have is out of a 99 Cobra R. it has a pulse output for the VSS & speedo. I may go with the new Dakota Digital unit.
I have a nice round speedo with the full gauge set i would like to use but i would have to put a pulse head in it. I may be able to have it done as a retrofit.
Garbz
I have a nice round speedo with the full gauge set i would like to use but i would have to put a pulse head in it. I may be able to have it done as a retrofit.
Garbz
Senior User
Joined: Jul 2012
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From: DE
Old thread but I didn’t want to start a new one. My speedometer seems like it’s 10 mph off. The needle doesn’t stop on zero but at like 7 o’clock area. Can this be fixed? And did they offer battery and oil pressure gauges that I can add to my current cluster?
Lead Gopher
Joined: Aug 2012
Posts: 10,041
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From: Seattle
If you are not moving at all and the speedometer needle is not pointing to zero then the speedometer head likely has an issue. Not much any of us can do to service a speedometer head since the mechanism inside is very delicate. There are places that can rebuild a speedometer head, but for the price it might be good to look at a new speedometer head. Is yours the round speedometer that goes from 0-100 MPH? If so there are some NOS or they do reproduce it since things like the Bronco also use it.
The numbers are sometimes different on them. The number 1 is an example. Some have serifs and some are sans serif. It's just the look of the font used.
https://www.ebay.com/sch/i.html?_from=R40&_trksid=m570.l1313&_nkw=C1TZ+1725 5-E&_sacat=0&LH_TitleDesc=1&_osacat=0&_odkw=C1TZ+172 55-E&LH_TitleDesc=1
If the link doesn't work search eBay on C1TZ-17255-E for some examples. I can see the software used on this site is adding a space in the part number. Bug most likely.
Chad
The numbers are sometimes different on them. The number 1 is an example. Some have serifs and some are sans serif. It's just the look of the font used.
https://www.ebay.com/sch/i.html?_from=R40&_trksid=m570.l1313&_nkw=C1TZ+1725 5-E&_sacat=0&LH_TitleDesc=1&_osacat=0&_odkw=C1TZ+172 55-E&LH_TitleDesc=1
If the link doesn't work search eBay on C1TZ-17255-E for some examples. I can see the software used on this site is adding a space in the part number. Bug most likely.
Chad
Lead Gopher
Joined: Aug 2012
Posts: 10,041
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From: Seattle
I have not looked into it on the speedometer head since mine are working OK, but you could check to see if it has any sort of external adjustment to the zero-based pointer like some of the other gauges do. The shop manual does not go into this and not a lot of other info that I can find. Here's a youtube that I recorded and uploaded. Might be applicable. I don't even want to remove one of my speedometers to check for you since they are working. Sorry about being lazy.
Chad
Chad
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From: DE
I completely understand and would agree. LoL, my luck on a working unit would stop working if Ibremoved it. I couldn’t find anything either. I’ll pull it this weekend and check. I have to replace bulbs as well. I just unscrew the cluster and it pulls out? Do I need to unhook the battery?
