Speed control repair

[domeboys]

My 1970 Challenger has the Speed Control option which worked fine until recently when I lost the speedometer and odometer. It appears the speed control unit seized up and it snapped the lower speedometer cable at the transmission end.

Does anyone have experience repairing them? Are they simple enough for a do-it-yourselfer or is there someone out there who specializes in servicing these speed control units? I would appreciate any help you can provide...

 

[heminut]

I don't know about now, but you used to be able to buy a speedometer cable kit that you could put the cable in the housing all the way and then cut it to length and install the other end. I did a couple way back in the day. Anybody else know if those kits are still available?

 

[heminut]

Here you go, I found it;
https://www.amazon.com/Dorman-03368-TECHoice-Speedometer-Cable/dp/B000CO8ZPQ

 

[domeboys]

Thank you, heminut. That could solve the broken cable. Does anyone have any insight on whether or not the seized Speed Control unit is repairable? If so, who/how? If not, are replacement units for sale?

 

[Chryco Psycho]

The way I look at most things is it is not working now so how much worse can it be if i take it apart & try to repair it , if it still doesn't work oh well ...

 

[domeboys]

Fair advice. I am just surprised that no forum members to have seen this have apparently worked on them or knows someone who has.

 

[Steve340]

It is most likely a fairly rare option and no one knows anything.
I have never seen a car with the original set-up only seen pictures in a book.
I would contact one of the known guys that does the top end resto work as I suspect parts will be pretty hard to get. They may know somebody.

 

[Chryco Psycho]

I have not seen an original unit .

 

[heminut]

I worked at a Chevy dealership (no flaming please!) from 1973 to 1976 and even then cruise control was pretty rare so I can't even imagine how rare it was on a 1970 E body!

 

[don selleck]

I was going thru a box of parts organizing for the new shop storage area and found a device called a pacesetter, seems to be an aftermarket cruise control, never saw one before

 

[domeboys]

For grins, here it is...

 

[JDMopar]

Maybe you could hook a vacuum gauge/pump to it and see if it holds when you pull a vacuum on it. There is a rubber diaphragm inside of it that could have rotted sometime in the last 50 years. If that is the case, maybe you could luck into a replacement diaphragm.

I took a factory cruise control setup out of a big C body in a junkyard and installed it in my 70 model 340 Challenger, which is ironically FK5....same as yours. I loved using it on the interstate. In late 81 and early 82, I did Cannonball runs between Asheville, NC and Clarkesville, TN every other weekend to see my girlfriend. I'd set the cruise on 80. When I would get off to get gas in Cookeville, TN, I would leave the car running getting gas and then get back on the road. I absolutely loved hitting the resume switch when I turned onto the I-40 on ramp! The cruise would suck the gas pedal out from under my foot, the car would momentarily kick back to 1st gear because I was going slow, bark 2nd gear and be back to 80 mph by the end of the on ramp! Ah, the good ol days.

 

[Challenger RTA]

If I recall clean the filter under the manifold
cover. It probably deterated. Also remove the gear cover.

 

[Xcudame]

The good thing is I think all the early Mopar cruise controls were pretty much the same as it was an bolt on option. So that might help with finding parts.

 

[Steve340]

You probably already know this the factory service manual has a section on the speed control.
There may be something in there that may help.
Accessories section.

 

[Steve340]

I recently watched an old re-run of Overhaulin were they did a ladies Barracuda Gran Coupe that had been purchased new by her Grandma.
It must have had cruise originally because I noticed the distinctive turn signal lever while they were stripping the car down.

 

[mrmopar340]

If you check the junkyards a lot of the C body cars had cruise on them. I think the bracket holding the accelerator to carb is different but you may find one in one of those old C's. Brake light switch for cruise was different if I recall correctly too. I've seen upper and lower cables on eBay but they are pricey and the cut to fit type are probably way more cost effective.

 

[340challconvert]

The cruise control servos are available used and rebuilt. The same unit was used for several years in the early 70’s on a number of Mopars. The cables would be the hard to find items. I just sold a set up with a mounting bracket and cables attached not too long ago! You can find individual parts for sale on occasion.

 

[BSG]

The way I look at most things is it is not working now so how much worse can it be if i take it apart & try to repair it , if it still doesn't work oh well ...

that's been my whole way of life

 

[domeboys]

An update. Upon removal of the gear cover, I discovered the problem. One of the four plastic (nylon?) tabs that hold in place the pins of the two metal flywheels broke off and another looks worn. (In the first photo, notice nothing is left to hold the flywheel pin in place.)

Does anyone have a Speed Control unit that is dead for another reason or parted out? It appears I need only the gear assembly.