Repairing my 1970 Neutral Saftey control switch

[Bill Balkie 24172]

       Hello ,
    For some time now my emergency Brake would not release automatically  when shifting the car into gear . The neutral Safety switch has 4 prongs that are made  out of pot metal and break very easily. My switch had a broken prong. The prongs are made for one bend and that's it . if you try to straighten the prong chances are they will break .  My neutral Safety switch assembly was loose on one side and the results were it would not hold or maintain the vacuum seal . I decided to add another prong made out of stainless steel .  3/8 wide X 3/4 long X .040 thick . Below the broken prong there is a cavity  that allows you to drill and tap a couple of 2-56 threaded holes without breaking into the main guts of the switch .  I drilled two matching  holes into the stainless steel  and formed  the stainlees to replace the pot metal prong . if needed you can do this to the other side as well . This method  will only work on the two side prongs . But i think those are the prongs the break the easiest .This also allows you to dissasemble the switch as often as you like . I installed the switch and every thing works as is should. The car starts in park and nuetral , the back up  lights work and break release  works perfectly .  I have added a few pictures .

     Bill



  Bill

[BlackCads]

Nice work!
Necessity is indeed the "mother of invention"!

["Cadillac Kid" Greg Surfas 15364]

Bill,
That's a great fix. it is a better solution than the JB weld I've used in the past since it leaves the switch still repairable when it needs it. In another 50 years, LOL.
Greg Surfas

[TJ Hopland]

On my 73 which was apparently a short lived design I drilled a hole in one part that then allowed me to use a zip tie to hold the plastic part down to the casting after the tabs had broke.   Did that over 20 years ago and its still holding fine.

[Bill Balkie 24172]

Thank You,   

       T.J., Greg and black Cads  for your Positive responce . I have seen these old switches advertised for more then $300.00 plus .  And who knows what kind of condition there in . When i was a kid i had to take that ball point pen apart just to see how it  works . Once you understand how mechanisms work.  You can usually  figure out how to fix it .  That is part of the challenge and fun of having a 50 or even a 100 year old car .

   Bill

[TJ Hopland]

So does anyone know why that switch seemed to change so many times?  I get why its not a super common GM part since not many (if any?) of the other cars had the vacuum parking brake release but even within Cadillac they seemed to change it a lot.   Just trying to get it right?   Did some of them have issues early in their lives?

[cadillactim]

They changed a lot because of the different columns (60-63, 64, 65-66, 67-68, 69-73), different transmissions (60-63, 64, 65-up), idle speed vacuum ports (67-up), and electrical interlock in low gear (71-73).

Tim

[TJ Hopland]

, and electrical interlock in low gear (71-73).

What was this? 

[cadillactim]

There were two extra terminals on the 71-73 switches. They were connected only when the shifter was in low gear. Apparently some kind of safety interlock.

Tim

[The Tassie Devil(le)]

My '72 only has the two pairs of terminals.   One pair for the NSS, and the other for the Reversing Lights.

Could what you are referring to be the extra pair of vacuum lines that could go to the front of the engine, to the Thermo Switch in the front left of the block, that controls the Vacuum Advance Vacuum to the Distributor from Full Manifold Vacuum?   These only allow the Distributor to receive the full vacuum when the engine warms up.

When driving a Manual Transmission car, I could feel when the switch allowed the full vacuum every time I drove it, as I was usually in second gear, driving in town, and the car would suddenly "Come Alive".   In this case, it was an electric switch, and we would override it by grounding the switch wire under a bolt head, so it still looked like it was operational.

Bruce.

[cadillactim]

Bruce

Definitely three sets of terminals on the 73 model, I've removed and rebuilt dozens of them. The master parts book show 69-70 the same (two sets of terminals), and 71-73 the same (three sets of terminals). You can use a 71-73 switch on a 69-70, just won't need the extra set of terminals. Maybe some of the 71-72 models only used the four terminals switch and others used the six terminal switch. I don't recall ever removing a four terminal switch from a 71-72, but hey, it's possible some had only four terminals.

I still don't know exactly what those other terminals activated, but they definitely had wires attached to them.

Tim

[TJ Hopland]

I do recall the system that Bruce mentions,  I recently worked on a car with a Muncie 21 in it and noticed an electrical switch in the trans that wasn't hooked up to anything.  Digging through the manuals eventually figured out it was supposed to be hooked to a solenoid that did something to the vacuum advance which had all been removed on this car.   

Seems to me that the auto transmissions used a speed sensor inline with the speedo cable or at least the cars I tangled with did but maybe that was because they were Cadillacs or Olds?  I remember those having the solenoid up on the intake but never looked close at the circuits to see if maybe they also had some sort of shift switch too.  I think it was an emissions thing but maybe being in low gear was an emissions exempt situation to get more power or maybe it forced the system regardless of speed?   Lower emissions in parades since Cadillac called low parade gear?


Just realized I have a tattered 73 diagram within arms reach....   one pair of contacts is reverse lights, second pair park neutral, and the third pair is for the seat belt buzzer circuit.     

Seat belt would make some sense on why it may have changed slightly year to year because they constantly seemed to be screwing around with the whole seat belt, key in door open alarm, and overheat alarm circuit and how they all interacted so maybe one year they could just piggy back on the park neutral but then the next year it had to be a ground instead of a hot to work or something like that.

I didn't follow all the circuits to see what is hot and what is ground and the electrical diagram doesn't show which contacts are closed when in that switch which seems a little strange since there are other switches on the same diagram that show what is connected when.  Maybe another sign that 'things subject to change without notice'? 

[Steve W]

Has anyone taken their NSS apart?

I have a 68 CdV, and my original NSS is on my bench. The replacement one I bought 10 years ago still works ( for the most part), but I thought I'd keep the old one and fix it up for a backup. Problem is, once I took it apart, there's a little spring inside that just popped it all apart. I can figure it out except for the orientation of the part with the spring. The spring goes into the hole of the slider, obviously, but which way does the rest of it go? It's very odd, and I know I'm probably not describing it correctly, but if you've ever taken one completely apart, you'll know what I mean.

[The Tassie Devil(le)]

G'day Steve,

The spring goes in the centre, the same as the other one that is at the end of the plastic piece.

The two projections at each end are just guides, the same as the other piece.

The Spring is positioned to apply pressure from the centre, and once there, it should be self-explanatory as to which way the brass piece orientates.

Bruce.

[Steve W]

Thanks Bruce,
But as you can see from the middle two pics...the brass contact plate can orient to the right or left. I just don't know which...and, no, it isn't obvious. I DO obvious very well! LOL!

[The Tassie Devil(le)]

It has to be in the centre, with the spring in the centre, and the two prongs (Guides) going down the sides.

When you lift it off, and place the spring in the central hole, it will become obvious.

Bruce.

[Steve W]

Look at the two pics. Blow them up. The spring goes into the plastic slide. Then there is the thing brass colored plate attached to the spring. And it can go either way! It is not obvious.

[The Tassie Devil(le)]

In the third picture, pick the brass piece up away from the spring, and move it sideways a tad, so the pins go down the sides of the plastic, it should fit.

I will try and find one I have here or another Cadillac, and see inside it.   It should be pretty much the same.

Bruce.

[Steve W]

The brass piece is connected to the spring. It's not an option to take it apart, as far as I know. It just has the option of going in the hole of the slider one way or the other.

[cadillacmike68]

Thank You,   

       T.J., Greg and black Cads  for your Positive responce . I have seen these old switches advertised for more then $300.00 plus .  And who knows what kind of condition there in . When i was a kid i had to take that ball point pen apart just to see how it  works . Once you understand how mechanisms work.  You can usually  figure out how to fix it .  That is part of the challenge and fun of having a 50 or even a 100 year old car .
   Bill

Bill, that was a Great idea! Now i can take apart my problem child 68 one here and have confidence that it will stay put together when I'm done.