Vacuum style Automatic Speed Control systems question

[Ross Wooldridge]

Hey Everyone,

As some of you know, I refurbish first generation Auto Pilot systems - rebuilding the dash dial controls, and refurbing the under hood mechanical servos, and renewing all the other components (bracketry, Bowden cable, wire harness, throttle linkages etc.).

This is the custom 65-66 Plymouth Fury/VIP and Canadian Polara/Monaco dash dial that I made for my car, since I have a Kilo Speedo.

Although it may be hard to see, I also made one for my 66 T&C since it also has a Kilo Speedo.

The point is that these are speed control systems that are entirely electro-mechanical.

Over the past few years I've done jobs on similar 65-67 Auto Pilot systems for at least 4 people who are both members here and are present within the various Facebook C Body groups. The most recent clients posted some nice reviews on Facebook, and the result is that I'm getting queries from others who ask if I have any expertise in the later vacuum operated systems, which I don't.

So - opportunity is knocking, and I am starting to think that I should learn about the vacuum controlled systems, and see if they can be refurbished as well, so as to perhaps increase my client base.

Therefore, my question is directed at those who have knowledge about those systems - how they work, and most importantly, where the problems crop up.

Vacuum diaphragm within the servo?

Problems with the turn signal stalk control?

Any insight that can be afforded me would be welcome, and if there are any tech bulletins or such on diagnosing and servicing these systems, I'd love to get them.

Thanks in advance!

Ross.

 

[bigmoparjeff]

If you didn't watch the Chrysler video that was recently posted about the vacuum cruise system, that would be the place to start. I can't remember what the original thread was about. I kind of think it started with one thing and morphed into talking about cruise and what year they switched to the slider switch. Hopefully a search will bring it up.

Anyway, from what I remember, likely failure points would be the mechanical governor and leaks in the vacuum part of the servo, like the diaphragm.

The unit itself was not serviced, so there will be no internal parts available for it, though I suspect the mechanical system was treated the same, and you were obviously able to overcome that.

Jeff

 

[tallhair]

If you can recall who posted the video that would help narrow it down or who was discussing it.

Understandable if you don’t

 

[Ross Wooldridge]

I'll search it - I remember the fact that there was a fair amount of information posted in that thread which had another subject and title.

Also, I don't think it was that long ago so it shouldn't be too hard to find.

 

[Ross Wooldridge]

Found it. Great info!

 

[John Kirby]

Found it. Great info!

Great, how about letting the rest of us know where it is.

 

[69 300 vert]

Great, how about letting the rest of us know where it is.

https://www.mymopar.com/downloads/mtsc/298.pdf

 

[Ross Wooldridge]

Lol... it's contained in this thread here:

Looking to change drums to disc from 71 CBody to 68 - anything to know?

 

[Mr C]

I had no idea you refurbished Auto pilots. Now I know where to send mine off when I do my 68 Imperial!

 

[Ross Wooldridge]

Yup, that's me!!

 

[Xenon]

And the charge for this service is....?

 

[CBODY67]

As I recall, ARA sold an accessory add-on cruise system (for vehicles other than Chrysler products) that used a Chrysler-like servo. I believe that the Chrysler system was a Dana/Perfect Circle unit, although the aftermarket PC units had a different turn signal stalk than what Chry used.

The earlier servos had two set screw adjustments, whereas the after-'70 or so units only had one.

Enjoy!
CBODY67

 

[Ross Wooldridge]

And the charge for this service is....?

It depends - the dash dial rebuild is typically $75 + shipping. That's what I advertise in the WPC Newsletter.

Servo refurb and maintenance is dependent upon condition - typically it's about $100 to dress and calibrate the internal point sets, lubricate, adjust and reset the servo internals, plus check over and remove kinks from the Bowden cable, lubricate.

A new label for the servo costs $20 - 25 - there are cheap repros out there for under $10, but the real deal foil label is $20 - I don't make any money on that.

Polishing the servo case can cost upwards of $150 - a fair amount of time involved to make it purdy.

Bracketry and linkage strip and repaint $350 - $450 - it's quite fiddly work and time consuming, and is dependent upon condition.

Wiring harness refurb - new terminals where required, rewrap with dry tape etc. $50 - 100

A total refurb and do over of the complete system runs about $800 plus shipping. That's every nut and bolt polished and anything supposed to be painted is redone in semi-gloss black, anything that's bare metal is coated in satin clear.

 

[traintech55]

Hey Ross, some info for you, The aftermarket ARA kits used the exact servo as the Chrysler unit. I was an installer for them back in the 70's. The dash switch changed from the rotary one to the slider in 1974. the two biggest problems I came across were not holding correct speed, cured by lubricating the upper and lower speedo cables, and not operating, mostly an internal problem. No matter what year, the system would make a click, when turned on from inside the car, you could hear it if you stood outside. The brake lite switch was part of the hold circuit to the servo. and the system operation was the same all the way up until 1989. the new servo unit, (1980 up), would interchange with the older units. Hope this helps.
P.S. let me know if you figure out how to repair them. I heard someone was making reproduction diaphragms.