I have a ford f100 1966 and my speedometer only is accurate up to 25 mph any can any give me any tips

 

Pull the speed o and clean out the dust and cobwebs. These work on induction and have no direct connection to the needle. Typically a cleaning will remove what is causing drag.

Garbz

 

Dave;
My '66 speedo works off of spun gears via the cable end. Maybe '67 switched to induction?

 

Inspect cable ends, pull the speedo and look for damaged gears and lastly; check speedo gear in tranny. JMHO

Unlessssss....speedo needle is bent or out of whack and hanging up on gauge face behind it.

 

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

 

That's right. I was thinking of the odometer.

 

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

 

To run with the mod computer?

 

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

 

 

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

 

 

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