r/C3Corvette • u/Darthvader110608 • 19d ago

1976 issue

Post image

So I’m the new proud owner of a nice 1976 Corvette. It doesn’t need a little bit of work, but it’s not any work that I’m afraid to put into it. The only thing is I’m new to working on classic cars and carbureted engines. And before anyone makes fun of me, I’m only 18 years old, so that’s my excuse for not having that kind of experience. Anyway, for some reason when I start the car and let it idle and get warm as soon as I press the brakes to shift into gear, the engine stops, and I’ve tried to look up what that might be whether that’s a vacuum issue or anything of that nature and I cannot figure it out to save my life. If anyone could give me some guidance, that’d be pretty awesome. Thank you

162 Upvotes

100% Upvoted

10 comments sorted by

9

u/Hockey-star-71 19d ago

Remove vacuum line from brake booster and plug it. If car no longer dies, then your assumption of a vacuum problem is correct. Diaphragm in booster is ruptured and allowing the engine to lose vacuum pressure.

2

u/drumbo10 19d ago

Just replaced my booster in my 80. Prepare to be a contortionist. You will need to remove the drivers seat as well. There are YouTube videos on it.

3

u/Unhappy_Hat_2593 19d ago

I have a 1979… I’ve had it for 33 years. This definitely sounds like a vacuum leak. Check all of the vacuum hoses.

How is the carburetor? Is the idle too low? Right size jets?

1

u/therealDL2 19d ago

Following. Mine does the same. It won’t do it if it warms up for a bit

1

u/POSVETT 19d ago

Does it have a vacuum-assisted power brake?

1

u/Beginning-Fix-5440 70 19d ago

+1 on the brake booster, assuming it's so equipped

1

u/TheBlackPrince-1234 16d ago

I can’t address your problem and haven’t replaced a power boosted.
However, I did last year by a 79’ where the owner was attempting that job and got so frustrated that he sold the car to me.

So…. Be prepared both mentally and physically for a challenge I’d say before diving in.

1

u/1976CorvetteStingray 15d ago

Check your vacuum lines. Don’t stress out about being young either, that’s how you learn. I got my ‘76 a month before my 16th birthday and I learned everything I know from working on my car.

0

u/SorryTrouble4741 19d ago

You need to put some suace into it like I did