it fluctuates a little - if I set it @ 50, it drops down to 47 before it surges in and gets up to 54 before it let's off

I seem to remember that despite their antiquity i.e. no computers, electronic sensors, etc., they were fairly steady and accurate back in the day.

Is there any adjustment or anything I should look for?

 

Perhaps the speedo cable needs to be cleaned and lubed.

 

yes, that it does for sure - hmmm duh!

 

speedo shop says $150 to remove and lube and reinstall both cables, says if it needs new ones, he will know right away and can make them. funny tho the speedo does not shake or bounce (the Toronado bounces but its cruise is perfect)

 

Ouch! That seems a bit steep to me.

If they have good service though...

 

You can lube them pretty easy yourself. I use powered grafite and it has worked well for me for the last forty years. Never had a speedo cable wear out. Had a few twist of though at high speed The easy way is to use canned air (stuff for cleaning computers. Squirt the grafite into the housing the blow the air in to force it the length of the cable. Beware this stuff is fine and it does not take much to go a long way

 

Then how DID they work, just out of curiousity?

I installed aftermarket cruise controls on both a '75 Chevy Nova and a '77 Chevy Caprice, and both times the kit used two magnets that you would attach to the driveshaft while mounting a pickup coil right next to where the magnets pass as the shaft spins. The moving magnets created a current in the coil in proportion to the rotational speed of the driveshaft. This was connected to a box under the hood which controlled a device that would open and close engine vacuum to pull on the throttle linkage.

So these certainly DID use electronics, as well as mechanicals. The system worked very well. I always assumed that the factory-installed cruise controls measured the car's speed similarly, though it might not have been at the driveshaft.

 

well ok I stand corrected but my point is that I do not mind a bouncy (yeah it does after all from 0-10) speedo, or even a noisy in the winter speedo - but the cruise has now become an issue because I am using it a lot more since I now have the foot operated tailgate window switch

and don't go a-hatin'!

<<<So these certainly DID use electronics, as well as mechanicals. The system worked very well. I always assumed that the factory-installed cruise controls measured the car's speed similarly, though it might not have been at the driveshaft>>>

I bet that's what happens in this box



so all that said, do you think I can just undo the cables at the aforementioned box, spray down in 1 and to the dash in the other and call it a day???

 

I agree.

To be honest, I don't know what you mean here.

 

The old cruise controls used clockworks and some electrical solenoids and relief valves to maintain cruise settings. I am trying to restore one for Lady...
The innards of the regulator box should be fairly self-explanitory...

Note the flying regulator weights...

It sounds much like a vacuum leak somewhere - a common issue.
The speed drop is where sufficient vacuum is struggling to build up in the servo unit (bellows unit). When it finally builds up it will cause brisk acceleration since the speed dropped so much. I assume you meant 54 when it let off??
Do the suck test on the servo unit and the brake pedal vac release. There is a big vacuum hose that goes through the firewall to the pedal release. With the pedal up, no vacuum should be lost.

Do the cable lube also. The cable should slide out of the casing for at the servo end and at the speedo end. Clean it with WD40 and then lightly grease with light grease and carefully reinsert. Do not force or it will kink and be ruined...

 

oh Rob honestly can I unscrew the cables from the cruise thing under the hood and spray? I can not imagine getting to the back of the speedo without chaos and blood and broken plastic - and should I open that thing up to like the pic and pray in there or is it all spring loaded and NOT RECOMMENDED?

 

I agree with Rob on the bellows/ pedal vacuum.
Whenever I see a nice bellows at the junkyard I ****** it right up. Many of them are ruined after all these years. For what it's worth, I discovered that the mid 70's mopar bellows are REALLY close to the original Oldsmobile bellows.

 

The cable going to the tranny should be able to be unscrewed from the regulator and the inner cable removed.
The other cable going to the speedo you can try that way, but I think it has to come out the speedo side.

Doing it this way is the way to do it right, as the old grease is prolly solidified like mine was. Spraying will help some and buy you some time before you can do it right. Yes, i hate pulling clusters too.

Now if the speedo needle is not bouncy, then I suspect your vacuum is leaking.

Please put the tools away - there are no user serviceable parts inside. Opening will void warranty and cause electrocution hazard. For every action there will be an equal and undesired reaction.

Seriously, do not open. Nothing will fly out, but the tempation to twiddle the little screws will develop, causing very strange things to happen.
The main valve in there does have a foam gasket that can deteriorate, but i have not found a viable solution to that yet. That is why mine is not on the car...
Check your servo and release valve.

J - Maybe you can become our cruise parts distributor! I sure liked how that servo I got from you cleaned and shined up - it looked like my NOS one afterwards! Keep up the collecting!!

 

one thing I know to be true - a Custom Cruiser needs to CRUISE

 

I agree.

If it is a vacuum leak hopefully it would be realatively simple to fix.

 

I'm thinking this may be a good opportunity to replace all vac, fuel lines just because they are almost 35 years old

 

For sure! I replaced all of the hoses on the engine; however, I still need to replace the rubber fuel hose at the fuel tank. Don't forget it, it deteriorates as well.

 

I did that last month and removed the broken original GM-stamped hoses!
Now the garage does not smell like gas any more!
Actually, i can smell the new tires now...

 

Oh yeah!

 

Just installed a factory correct cruise on my 72 442. Yes make sure all of your hoses are in good condition. BUT, I think to fix your speed issue, like I did per the service manual, make a SMALL adjustment to the transducer via a small allen wrench set screw. try that first. My thoughts are that is cables are dry and need lube, they would be noisy and you would have wavering speed problems all the time.

 

thanks, wagon is in the shop, will send him this link - the Toronado is not much better - set it at 60, drops to almost 50 before it kicks in and surges and varies between 55 and 60