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Vacuum Issues

Hello Gentlemen,
I own a ‘64’ Montclair Breezeway. I just replaced the 390 that’s in it, and it was rebuilt and has less than 16,000 miles on the motor.
I believe I’m having vacuum issues in the motor and the transmission.
When I’m at a complete stop and I want to floor it, there’s a “pffft” sound and it acts like it wants to die until I ease off of the pedal, then I ease into it and it’s fine. Although, it takes time to shift, and it does so almost sparatically. Even rolling down the road at say about 45mph, I floor it with some lag and it takes a second for it to really get moving. When he gets going though, it runs like a scalded dog. I love this car, it was a 3rd Deployment gift to myself. I’m currently on my 4th combat tour in Afghanistan right now. I’m stationed at Fort Campbell,KY with the 101st Airborne Division. I’m a Heavy Wheeled Operator.
Another vacuum issue is my Brake Booster isn’t working, as you guys probably know, stopping a car like mine with manual brakes is a job in itself.
The breezeway rear window still works too. I added the make & model as requested, only Montclairs aren’t listed.
Thank you guys!
Look forward to listening to you fellas again when I get home in June. Merry Christmas & Happy New Year!!
Sincerely,

SGT Josh Lindstrom
101st Airborne Division 3rd Brigade
FOB Salerno
Afghanistan

Having a problem with the brake booster would likely lead you to believe that the engine problem is also vacuum-related, but there are other possibilites for the hesitation, in addition to a vacuum problem.

Chief on my list would be the accelerator pump in the carburetor. If the nozzle of the accelerator pump is gummed-up, or if the accelerator pump is actually damaged (by ethanol in the gas, perhaps?), that could account for the hesitation that you describe.

Another possibility is that the ignition timing is “off”, and that it needs to be advanced a bit.

Now–here’s the trick–to find a mechanic who is actually familiar with carburetors and their quirks. Younger mechanics may never have worked on a carb, and if they are really young, they may have never even lifted the hood on a car with a carb-equipped engine! Even adjusting ignition timing is something that many young mechanics are not knowledgeable about.

So…I would suggest finding an indy mechanic’s shop that employs at least one guy who is over the age of 50, as that guy would certainly have more expertise on your probable issues than the bulk of younger mechanics.

When the car is in the shop for the hesitation problem, I urge you to have the brake booster examined, and replaced if necessary. It would certainly not be unreasonable to believe that the booster’s diaphragm is simply worn out after almost 50 years!

If you are lucky, it is possible that there is just a disconnected or damaged vacuum line (or two), but don’t be surprised if actual repairs to both the carb and the brake booster are needed.

P.S.–Thank you for your service!
Have a Merry Christmas, and…please stay safe!

Thank you Sir. I sure appreciate the info. I want to get my car ready for a few car shows when I get home. Funny thing is, the shows I’ve taken him to alot of people say they’ve never even seen a car like mine before. I did some reading up on the sales and popularity, and apparently they weren’t that popular.
I’m tossing around the thought of converting the drums to discs. Still trying to figure out which Ford / Mercury vehcle would be compatible to pull from a salvage yard to save myself some money. Again, thank you for your response Sir. Have a good day.

When I was kid our neighbor had this car. Rear sliding window too. Nice car!

I would ask if you’re using ethanol gas in the vehicle? Because if you are, it could be the root of your problem.

And I also thank you for your service to us, and to our country.

Tester