1973 Electra Cruise Control?

[Guest 49 plymouth]

Hi I just brought a 1972 Buick Electra, I am driving her back from South Arkansas to NC. She had sat In barn for 10 years, she started up with new battery, and with new tires and oil change, we set off even original gas, she is running like a champ, 600 miles so far, can somebody tell me how operate the Cruze control, I found the button to engage, but not sure how to control. Thanks

[JohnD1956]

Above 40 MPH you simply push the button in, and if it is able, it will engage. Then to stop it you tap the brake. There is no provision for adjusting it once it is engaged. If you want to go faster just step on the gas and when you reach your new speed just push the button. Note, you push the button and release slowly, and there is a light on the dash to show when it's engaged.

Would love to see pics of your 72. They are sweet cars.

[Guest 49 plymouth]

Ok thank you I pushed the button and it just kept speeding up, ha bit of a shock when you press an button and the car kicks down and is off like a scolded cat. I can't see how to post pic but will try fig it out.

[Guest 49 plymouth]

It's a great car I am loving it

[Guest 49 plymouth]

[Guest 49 plymouth]

This is before we set off

[NTX5467]

If you push the "Set" button and the vehicle speed increases, there is an issue with the transducer itself. If it would increase or decrease speed by a little from the speed when the button was pushed, that can probably be tweaked in the "Set speed" adjustment, but for what you describe, it might take an overhaul/readjustment of the transducer rather than just tweaking an adjustment screw a little each way. The transducer is the item the speedometer cables enter/exit from, usually on the lh fender skirt, under the hood.

As mentioned, if you desire a higher speed, accelerate and then push the "Set" button at the new speed. Similarly, if you want to "coast", just push the button in and hold it until the desired speed is reached. Only Ford and Chrysler had factory cruise controls with "Accel/Decel" functions, back then.

Congrats on your find! Those were great cars!

Please keep us posted on your progress.

Enjoy!

NTX5467

[Guest 49 plymouth]

Thanks for the info, I am sure I will have lots of things to sort after sitting that long.

[Guest my3buicks]

I picked up a 72 Electra in Dallas once and drove it back to Columbus, it had the same issue, I kept playing with it and it actually got much better as the trip progressed. My first 72 Centurion did that as well, I got it to the point that it would only jump 5mph when engaged, I would just set it 5 mph lower than I wanted to go.

[Guest 49 plymouth]

Yes lots of stuff, has started to work as we travel, I will give it a try

[bhambulldog]

It's a great car I am loving it

Grreat!!

Congratulations !!

[MrEarl]

Congrats! Thanks for sharing your trip with us. Once you get home and settled in please share more about the car down in the Me and My Buick forum.

Happy Trails

Edited January 3, 2015 by MrEarl (see edit history)

[JohnD1956]

Looks like a fun car. Next stop just check for a deteriorated vacuum line at the transducer. You may be able to trim the line back an inch and reconnect, but it probably won't last.

[rocketraider]

Good find.

There was a reason other Divisions stuck with the Perfect Circle governor cruise control as long as they did...

I've always said the AC vacuum transducer cruise was a half-baked design. The three cars I've owned with it generally had to have a rebuilt transducer every 3-5 years and even fresh ones would often hucklebuck or gain/lose speed after setting. I have never replaced a Perfect Circle governor unit.

[Larry Schramm]

I would probably disagree with "half baked" statemetn about the AC Cruise system. Used to work in the department making them through college and I have had minimal problems with them.

If you engage the cruise and the car starts speeding up, the cause is a small bronze bushing in the transducer that wore out.

[NTX5467]

Might "half-baked" refer to the fact that while Ford and Chrysler had "resume"/memory cruise controls, GM didn't get one until the mid-1980s. Definitely LATE to the party, in that respect.

GM obviously had their reasons for keeping that system for so long. It worked well for them, though.

As things progressed, though, there were MANY different transducers relating to different car lines, how the systems were turned on and off, and which type of engine (gas or diesel). Oh, and the later adaptation of an extra vacuum chopper on the transducer, which was on the "resume" cruises. As I recall, the mechanicals of the transducer were not that complicated to fix (IF you knew how it operated and had access to repair parts.

Enjoy!

NTX5467

[old-tank]

At least the AC units are still available...the Dana unit that came on my 76 Olds is made of 'unobtainium'.

[Larry Schramm]

The worn out bushing/ bearing could probably be fixes. I have a couple of extras in the garage and just have not had the time to try to fix them. It should be a farily simple fix. Might try to put in a needle bearing instead of a bushing if I can find the correct size.

I will try to put up some pictures of the problem.

[JohnD1956]

I'd like to see that Larry. I have two now that have issues. I did take one apart but I had no clue what I was looking for. I was able to get a good one last fall at the junkyard. Now this one is starting to wobble the speedometer.

[Larry Schramm]

Here is the side of the transducer that the speedometer cables connect to. The one on the left is a good part and the pointer is showing the bushing that goes bad in the center of the shaft. The part on the right is one that has a bad bushing. You can see the rubbing on the magnet because of the bad bushing.

If the car starts to have the speedometer jumping, disconnect the cables and get a new unit or it will evetually bind up and break the speedometer cable.

I am not encouraging anyone to fix these as this is a part that could cause the car to accelerate if not properly repaired. It is best to have this part repaired by a qualified repair facility.

[Guest 49 plymouth]

Thanks for all the info. Mine overcompensates the speed drops off, then the car changes down speeds up until you are going faster than you want. And starts over slowing down too much. I found if you kept your foot very lightly above the gas pedal it would not lift off so much and it worked better. When it engages, that is often it does not engage at all when you push the button.

[Guest 49 plymouth]

Yes I have a lot of other Jobs to worry about so I am not worried about it at the moment

[NTX5467]

Disconnect that thing!

I had two go bad and floor the gas... Besides, a cruise control can't anticipate hills and will lug the hell out of the motor and the torque converter..

It all depends upon the vehicle speed and part-throttle downshift calibrations. Most will no engage below about 30mph.

Back in about 2006, I rented a new LeSabre and set the trip computer to "Instant Fuel Economy". I tested the "keep the throttle steady", "don't decelerate going down the hill, gaining speed", and a few other driving techniques (which might work fine with a carburetor). I did it on the (GWBush Turnpike in northern Dallas, TX). I then watched things happen with the cruise engaged, "doin' its thing".

End result, keeping a steady throttle foot, uphill and down, resulted in slower uphill speeds and higher downhill speeds and worse fuel economy. Keeping the same throttle setting on the downhill side allowed the car to gain some speed, but only gained 5mpg over the flat-land mileage. Not a good compromise.

I'd previously tested the "slow, steady acceleration" on other vehicles and determined that was not that good, either, as it kept the trans in lower gears longer than a slightly faster acceleration (which would also allow the vehicle to reach "cruising speed" sooner, for greater overall economy). On the LeSabre, the difference between an 8mpg acceleration and a 6mpg acceleration was significant enough to keep drivers behind you satisfied with your progress. Plus, as you got to speed sooner, you then could back out of the throttle and coast more often.

As the cruise control "reads" additional engine load, as soon as the road speed drops more than 2mph, then it tries to maintain the desired speed by adding throttle until it's reached and/or maintained. If needed, the trans would downshift to assist things. Certainly, this additional road load and speed maintenance will drive the Instant Fuel Economy to near-single digit levels. BUT, as soon as the load is decreased, throttle is removed. If the vehicle is now going downhill, the "coast" mode is functional and Instant Fuel Economy will go to about 99mpg (some Buick 3800 V-6s, earlier on, would only go to 68mpg, as other engines would go to 99mpg). So, if you spent as much time going up the hill as you spend going down the hill's other side, then what's the average of 10mpg and 99mpg?

Once, in an Impala SS, fwd 5.3L V-8, I was cruising at 65mph with the cruise on. A pesky F-250HD diesel was approaching from the rear. I floored the Impala and ran it up to about 100mph, then coasted back down to 65mph. During that short burst of acceleration, the IFE was about 8mpg, but when I coasted back down, it was all at 99mpg. The acceleration was probably for about 10 seconds, but the coast was about 45 seconds. End result, the Average Fuel Economy went UP, due to the coast period.

Also, in that LeSabre, I tried to anticipate load changes with my foot vs the cruise. Cruise won every time! It read the decrease in load much quicker than I did, although its functions were a little more aggressive than mine. Prove to me that it's best to let the cruise handle things, when conditions permit.

With a carburetor, the differences are not quite as great, but they are still there. If you might want to experiment, in a "safe environment" and with an open road and little traffic. Have the cruise set to about 60mph, then pull over and stop. As you accelerate again, when you get to 30mph, hit the "resume" function and hold on. You'll find out, real quick, just how much throttle and gears it'll use to get to 60mph again! Do so at your own risk!

If you might be approaching a long, uphill grade, you might want to manually select the next-lower gear earlier on, so less throttle will be used to maintain speed, while also clicking the cruiser "off". When you hit "flat land" again, manually upshift the trans and re-engage the cruise.

ONE other thing is to check the calibration of the speedometer. I normally use Interstate mile markers for 10 miles at 60mph to do this. It makes the odometer reading check easier. 60mph = 60 seconds/mile. For the speed check, you'll need a generally flat stretch of road, for a few miles. It CAN be challenging to maintain a completely-steady speed for that long, or you can counter the faster spikes with slower spikes of equal time. Then, with the cruise, you can better know just what your speed is.

Thanks for those pictures, Larry! With the materials we now have, plus lubes, it ought to be possible to have enhanced durability and reliability from those units.

As for the "needle jumping", that can ALSO be caused by the cable housing having worn away enough for the speedometer cable to actually contact the metal mesh in the cable housing itself. Once the "compacted wire" (cable) might "meet" the loose mesh inside of the cable housing (for strength and rigidity), that can cause "a mess" inside of the cable housing. IF it's on the input side of things, it can also cause problems with the speedometer gears in the transmission tailshaft housing. If it's on the speedometer side of things, it can cause issues all the way back to the speedometer gears, but not hurt the speedo head itself. IF the real cause is in the transducer, best to replace the transducer soon!

GM had an ST800 Speedometer Lube, years ago. It was a larger tube with jelly-type lube in it, just for speedometer cables. I'd recommend that if the car has many miles on it, it might be best to just replace the speedometer cables as a matter of course. The existing lube has probably dried-out, I suspect. Many times, the ACDelco replacement replacement cable units are "cut to fit", so you might need to contact the man in Michigan for a new set he might build for the application, moreso for the internal cable, but possibly the cable units (pre-assembled, lubed, application specific) are "plug and play".

Enjoy!

NTX5467

[Larry Schramm]

Some time when we are together, I can show & explain how to get rid of the speed up or slow down when engaging the cruise control. It is an adjustment.

[Guest 49 plymouth]

Oh ok thanks, my first job is the gas tank it's leaking fuel, from the top. I am hoping it's from the sender. So going to drop it and hopefully fix and clean.