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Hello,

lets try a second time.
My name is Stefan, I am from austria and I am owning a 1965 Pontiac Grand Prix.
I am restoring oldtimer for around 12 years now, but the pontiac is my first US-Car.

Because it isn´t that easy to get spare parts here in europe, especialy in austria, I have to ask first instead of just try and destroy something :rolleyes:

So here are may questions:

I have a vacuum gauge in my car, but it is not working.
I think I know why its not working, but I am not sure. How are the vacuum hoses routed in the engine department, and which parts have to be connected with which ones? Perhaps somebody could send me some detail pictures ore a drawing of a workshop manual which shows the complete installation of the vacuum hoses.

Is there any posibility to adjust the stearing gearbox?
There is a screw on top of it, on the outside there is a nut, and inside the nut there is a kind of Torx-screw. I am not sure if i can adjust the steering with that screw (maybe I should post a picture of the screw I am meening?)

And the third qestion I have, does anybody have an electric wiring diagram of the car, that would help me a lot.

Thanks for your help,
with best regards
Stefan
 

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Stefan,

Nice car.

Power steering? or Manual steering box?

What makes you believe you need to adjust your steering box? Remember, these older cars do not respond like today's rack & pinion steering. I would not adjust it just for the sake of adjusting the steering box. If you do it wrong, you can damage the box, or worse, cause the steering box to bind up.

Have you checked or replaced the idler arm? tie-rod ends? Drag link? If these are worn out, they will cause loose steering.

Can't help you on the vacuum gauge lines. I would think the line goes to a vacuum port on the engine directly, or off of the carburetor. I have seen some Pontiac intakes having a single vacuum port just in front of the carburetor if I remember correctly. You should be able to trace the line by following what vacuum lines you do have on the engine/coming off the carburetor.

For a wiring diagram, you might have to locate and purchase a Pontiac chassis manual for your year car.
 

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@PontiacJim: Thanks. It has power steering. Thats right that an old car won´t react like a new one, and I am clear that there is some loose steering in this old cars. But if there is too much loose steering, I know it from the german oldis I was working on, you had the possibility to adjust the steering a little bit with this screws.

But you are all right, at first I will check all moving parts on the front and if it is necessary I will replace the worn out parts and see if steering will change :thumbsup: .

I now looked at the vacuum lines, and I found the following ones. One that comes out from the engine leading to the intake manifold. One that comes out from the back side of the carburator which divides itself to the brake booster, the ditributor and one metal line that runs underneath the car, maybe for the gearbox?!
And one vacuum line runs out directly from the firewall to the expansion valve of the aircondition.
But what are the connections for which I have marked with an red arrow?
Could it be possible that the short second one in the firewall will lead to the vacuum gauge?

@05GTO: Thanks a lot, that was exactly what I was looking for!

@the65gto: Hey, thanks! I have seen you are from florida, my grand prix also was running in florida until 2011.

Thanks,
with best regards
Stefan
 

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Amazing looking GP Stephan! I've never seen one all White like that, and I love the wheel covers, don't change a thing!!
 

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Stefan,

In the first photo, an arrow points to a carb stud/vacuum line fitting which is ported directly into the intake manifold. This would give you direct manifold vacuum. It could be used for your gauge. The second port on the top of the carb is found on some AFB carbs while others do not have it. I do not know specifically what the port is used for. The carb was used on many years and GM cars, so it could have several applications that I am not aware of. It would not be direct manifold vacuum as it is above the carb throttle plates and the amount of vacuum would be dependent on the opening/closing of the throttle plates -so I believe this would be called a "ported vacuum" connection. The vacuum gauge would not go here.

The second picture shows the single vacuum port on the manifold in front of the carb as I described in my earlier reply. However, it looks like the lines are incorrectly hooked up. If I am right, the larger hose is for the PCV valve at the top of the engine valley pan. This hose should be connected to the carb. There should be a large tube/port just between the idle adjusting screws on the front of the carb. It looks like there is a plastic "T" fitting that connects the manifold vacuum fitting to the PCV valve and then the hose goes around the side of the carb ......and I cannot see where the other end attaches? I don't think this is correct if I am seeing everything as it is in the photo.

The line coming out of the firewall could indeed be for your vacuum gauge. Can you test it by extending that piece of hose and then hook it to the vacuum fitting/carb stud at the back of the carburetor as shown in the first photo? If it works, then get a new vacuum line the length you need it and go from your vacuum gauge on the console and attach it to that carb stud/port.

Finally, check all your front steering parts for wear. Often, the Pontiac idler arm gets worn and can cause a loose feeling in the steering. The drag link and tie rod ends can wear out quickly if an owner does not keep up with greasing them regularly.

I have a book that tells how to take the play out of the power steering box, but I have never done this myself. You have to do this correctly or you damage the steering box. This would be the last thing I would do if the above parts did not fix the problem.
 

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Hey Jim,
thanks a lot for your answer.
That gives me an idea how this system should run.
I will try the things you said me, and then see if the "missing vacuum line" gets found and the vacuum gauge will run again.

I´ll post one more picture of the carb, maybee you can see some details that you havn´t been able to see in the first pictures.

Thanks,
best regards
Stefan
 

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@ALKYGTO: Thanks a lot. As i saw the first pictures of the car, I thought white with white dosn´t fit. But when i saw it live, I liked it very much.

I am really happy with the car, but I have to change the wheels, i dont really like them. I will put some classic american racing in 15" on, and then I think the Grand Prix is perfect for me :seeya: .

With best regards
Stefan
 

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Hey Jim,
thanks a lot for your answer.
That gives me an idea how this system should run.
I will try the things you said me, and then see if the "missing vacuum line" gets found and the vacuum gauge will run again.

I´ll post one more picture of the carb, maybee you can see some details that you havn´t been able to see in the first pictures.

Thanks,
best regards
Stefan
Stefan,

Looking at the carb, you do not have the vacuum port in the front between the idle screws. I did some web searching and found a carb just like yours and it was a factory Pontiac 1966 Carter AFB, so your carb looks to be original.

Some AFB carbs have the big vacuum port at the rear which I believe connects the vacuum hose to power brake booster? From the photo, the big vacuum hose looks like it goes down near the distributor. I found a photo of a 1966 Tr-Power and the hose in question goes to the PCV valve which is at the rear of the intake? If so, then this is correct. The problem I see is the other end.

Where does the other end lead to? Later Pontiacs have the PCV valve in the front and I thought that was where that end was going. Does th hose connection in front of the carb go to a vacuum port/source that is directly tapped into the manifold? If so, then I don't think you need that plastic "T" fitting and the hose should go directly from the PCV valve at the rear to the manifold vacuum port fitting. Then simply cap off the small vacuum port that is tied into that plastic "T" fitting.

Make sense? Eventually we will get it figured out.:thumbsup:
 

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Hey Jim,

thanks a lot. It seems you know a lot about this old engines :thumbsup:
I will check your hints tomorrow, cause it´s already late here in austria :wink2: .

I will post my progress tomorrow.

Best regards
Stefan
 
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