More Speedo questions

[Twins]

My Speedometer needle was bouncing above 50mph. Ordered the "concourse correct" cable which I believe is about 61 inches long. The retaining clip on the end didn't fit through the hole in the firewall a s it's slightly larger than what I have on the original cable. If needed I can enlarge but wanted to try and rehab the old one first.

I pulled the cable from the sheath on the old unit and cleaned everything then lubed. Looked good and reinstalled. While the ol one as out I straighnted as best I could and it appears to be about 73 inches long. It also has a metal band on the sheath a few feet from the tranny that fits perfectly into a clip under the car. So it seems correct.

So I did not bother trying the new cable which seems to have to be bent rather then curved to get through the firewall as it's about a foot shorter than what I have now plus I would have to enlarge the hole and wanted to wait first.

.

So my cleaning etc didn't work and I still have the bounce which may very well be the Speedo itself. There's a question here somewhere....does anyone know if the 73 cable is indeed longer than the one generally sold as correct for these cars and where I can get one? Thanks.

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[Omie01]

I just took a speedo cable out of a 73 with an FMX trans, and it is a 2 piece cable, there is a little round sensor of some sort where the 2 halves of the cable meet. This may make the cable overall longer. The sensor thing is located right behind the instrument cluster before it goes through the firewall.

 

[73pony]

My 73 cable was about 61 inches long. I replaced with one my local parts store had in stock and it worked perfectly.

 

[Twins]

I just took a speedo cable out of a 73 with an FMX trans, and it is a 2 piece cable, there is a little round sensor of some sort where the 2 halves of the cable meet. This may make the cable overall longer. The sensor thing is located right behind the instrument cluster before it goes through the firewall.

Yup.  I had read at some point that the 73's were two piece so that might add to the length.  Maybe the prior owner of my car replaced the cable with a one piece and he used some longer part to cover the distance.

 

[Twins]

My 73 cable was about 61 inches long. I replaced with one my local parts store had in stock and it worked perfectly.

You got me thinking that I should just enlarge that firewall hole a tad and get that replacement cable through it and give it a shot with the 61 inch model.  

In the end, I might be wasting my efforts and abusing the cluster by pulling it repeatedly as it may just be the speedo.....still, you know I want to try!

 

[73pony]

Mine was bouncing. The new cable solved it. I did pull apart the new cable and lube it up good with graphite prior to install though. Just a thought. I did not have to enlarge my firewall hole though.

Here is a link to the one I used. My car was an FMX and this one indicated for a manual but the one in my car was 61 ish inches and this one was 63 so I went with it, fit perfect and works great.

http://www.autozone.com/drivetrain/speedometer-cable/pioneer-speedometer-cable/77609_1514_1765_3498_4993

They also show an automatic one that is 80 inches.

http://www.autozone.com/drivetrain/speedometer-cable/pioneer-speedometer-cable/77599_1514_7543_1277

 

[OMS]

auto cable is 63   http://www.ohiomustang.com/store/order_page.asp?itemid=2744

4 speed cable is 73   http://www.ohiomustang.com/store/order_page.asp?itemid=2745

 

[Twins]

auto cable is 63   http://www.ohiomustang.com/store/order_page.asp?itemid=2744

4 speed cable is 73   http://www.ohiomustang.com/store/order_page.asp?itemid=2745

I was hoping you would weigh in Don.  So, based on that 73 inch measurement my car (which was born with an auto and still has one) has the wrong cable!  The one that was in there was indeed 73 inches long for the 4 speed!

I'll have to watch the routing and use the 63 inch one I have.  Should be fine then.

Thanks!

 

[Twins]

Mine was bouncing. The new cable solved it. I did pull apart the new cable and lube it up good with graphite prior to install though. Just a thought. I did not have to enlarge my firewall hole though.

Here is a link to the one I used. My car was an FMX and this one indicated for a manual but the one in my car was 61 ish inches and this one was 63 so I went with it, fit perfect and works great.

http://www.autozone.com/drivetrain/speedometer-cable/pioneer-speedometer-cable/77609_1514_1765_3498_4993

They also show an automatic one that is 80 inches.

http://www.autozone.com/drivetrain/speedometer-cable/pioneer-speedometer-cable/77599_1514_7543_1277

Thanks.  If for some reason I have an issue with the 63" one I can try the longer one there.  I will lube up the new cable as suggested.  It's good to know that in your case that solved the issue.  I hope I am as fortunate.  

 

[secluff]

The device in the speedometer cable is a speed sensor and was used to send vehicle speed info to a relay called a exhaust gas recirculation control switch. That was used to control the EGR valve, vacuum advance, and ported vacuum switches. Was used on 73 351C, 400, 429, 460, and 460 interceptors, and in 1974 on the 460 interceptor's only. 1975 saw the introduction of catalytic converters and a major change in EGR and related emissions systems so this system was no longer used.  A lot of people mistake this for the cruise control speed sensor since it is in the same location and has the same appearance as a car that has factory cruise control. Cruise control was not a RPO (regular production option) on the 71-73 Mustangs. A lot of these were probably tossed over the years as the two piece cable was not used on all the 73's and replacement parts were scarce. Probably safe to say that most of the switch's (9E447) the speed sensor sent it's signal to are no longer functioning. The production one piece cable for Automatic (non drag pack) cars was 61.5" and the service replacement  was 67". Production one piece manual transmission cables ranged from 53 13/16" to 71 13/16" depending on engine, 3 or 4sp, differential ratio combinations.

Don @ OMS would probably be  good start as he knows these cars and what fits the best in a world where repo people don't think of us too often!

 

[Twins]

The device in the speedometer cable is a speed sensor and was used to send vehicle speed info to a relay called a exhaust gas recirculation control switch. That was used to control the EGR valve, vacuum advance, and ported vacuum switches. Was used on 73 351C, 400, 429, 460, and 460 interceptors, and in 1974 on the 460 interceptor's only. 1975 saw the introduction of catalytic converters and a major change in EGR and related emissions systems so this system was no longer used.  A lot of people mistake this for the cruise control speed sensor since it is in the same location and has the same appearance as a car that has factory cruise control. Cruise control was not a RPO (regular production option) on the 71-73 Mustangs. A lot of these were probably tossed over the years as the two piece cable was not used on all the 73's and replacement parts were scarce. Probably safe to say that most of the switch's (9E447) the speed sensor sent it's signal to are no longer functioning. The production one piece cable for Automatic (non drag pack) cars was 61.5" and the service replacement  was 67". Production one piece manual transmission cables ranged from 53 13/16" to 71 13/16" depending on engine, 3 or 4sp, differential ratio combinations.

Don @ OMS would probably be  good start as he knows these cars and what fits the best in a world where repo people don't think of us too often!

Thanks Secluff.  I didn't recall all the details about the function of the speed sensor.  The replacement cable I have is the one Don mentioned so I will go with that.  Interesting about the length differences.  It looks like someone used the manual version on mine.  After over 40 years and a few owners you never know what's going to be used on your car.  

 

[Twins]

I should also mention that the end of the cable in the car now as a little plastic piece - almost shaped like an arrow. The replacements don't have that. It kind of guides the cable into the back of the speedo. Is this supposed to be transferred onto the end of a new cable?

 

[secluff]

Twins, the white plastic collar is what actually locks the cable on the speedometer head and should be permanently attached to the cable housing to effetely hold everything secure. The flat area the yellow arrow is pointing to is where you would depress to release it from a groove in  the speedometer head. I realize as tight as things are behind the instrument cluster that some may feel the chances of the cable coming off the speedometer head are slim. But "Murphy's Law" says that anything that can go wrong....will! And that's a PIA job I wouldn't want to do more than once in a day's time. Quality cables patterned after the Ford versions should have the collar attached so it will be held firmly against the speedometer head!  

 

[Hemikiller]

The 4-speed cable is longer as the speedo port in the transmission on the passenger side, the autos come in on the driver's side.

 

[Twins]

Twins, the white plastic collar is what actually locks the cable on the speedometer head and should be permanently attached to the cable housing to effetely hold everything secure. The flat area the yellow arrow is pointing to is the where you would depress to release it from a groove in  the speedometer head. I realize as tight as things are behind the instrument cluster that some may feel the chances of the cable coming off the speedometer head are slim. But "Murphy's Law" says that anything that can go wrong....will! And that's a PIA job I wouldn't want to do more than once in a day's time. Quality cables patterned after the Ford versions should have the collar attached so it will be held firmly against the speedometer head!  

Yup. I'm good with the plastic collar. What I also have is a little plastic piece at the end of the actual cable wire. It goes intoo the back of the Speedo as opposed to bare wire.I probably have some kind of aftermarket speedometer cable with this weird end. Hopefully it didn't mess up the speedometer itself over time. When I pull the cable out again I'll take a picture of it to show you what I mean.

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[Twins]

The 4-speed cable is longer as the speedo port in the transmission on the passenger side, the autos come in on the driver's side.

Someone must have just grabbed the 4 speed cable for mine.  Thanks for the explanation.  I was thinking that must be the case in terms of where the port is.

I'm getting good at pulling this cable out!

 

[secluff]

Twins, I let the part about the plastic piece at the end of the actual cable wire slip past me! I'm used to the Ford cable core that used the metal ends. A lot of the aftermarket cores I've seen have the plastic tips to fit the end of the cable into the square hole in the speedometer head or the driven gear. Ford had a universal core that could be cut to size and had a metal cable core tip and a swage to permanently attach the tip to the cable core. The illustration shows the cable tip and swage that was included in the Ford cable service replacement part  Hopefully this time I've actually answered your question. :whistling:

 

[Twins]

Please! You've given me more information then I could possibly hope for. It would be natural to think I was talking about the plastic collar. I'll have to post a picture once I pull the old cable again but the part is sort of like what you show above. The new reproduction cable I have just terminates in a square end to go into the Speedo. Hopefully this is not an issue.

It's A small thing fixing a speedometer cable but I'm learning and everytime I tackle a thing like this I see a little more about how other parts of the car works and I'm able to do more myself.

I thank all of you for your help in that. When the repair actually works and perhaps I get to see that needle sweep instead of bounce along its enormously satisfying.

As you all well know bringing the car to a shop for something like this usually not only ends in a high bill but more importantly disappointment. I wind up doing the job over anyway.

Which is another lesson unto itself!

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[secluff]

Lol...Information overload! Lots of parts involved in "Screwing" one of these Beasts together. Like lots of other forum members here I've got scars from busted knuckles, mashed fingers, and lots of cuts and scrapes. It all counts for valuable experience I wouldn't trade for anything. Yep, you will save a lot of $$ doing this job yourself, will learn more about your car, and will get the satisfaction of seeing the speedometer working properly and that you repaired it!