This weekend while riding around with the boy in the car, I decided to see just well, or how poor, the brakes work. These brakes are pretty spongy and are at the top of the list of things to rebuild. As spongy as they are I've always assumed they won't actually stop the car quickly very well so I keep plenty of distance between me and everyone else. While on a long downhill 9% grade running around 35MPH, I told him to hold on tight while I was going to nail the brakes. To my surprise, they actually work fairly well and will almost lock up. To my bigger surprise, it kills the engine (with the clutch in of course). However I can come to any stop and never have to worry about killing the engine. Thinking it was just a fluke, I tried it again. Yet again, I killed the engine.

The rest of the way home all I could think about was how the heck I was able to kill the engine just by stomping on the brakes. Well, I finally dawned on me what is happening. The battery is falling forward during the hard braking losing connection at the posts! I'm pretty bad about just putting the cable on the battery and giving it a little twist to lock it on and when I'm done, I just twist it off. It has never caused a problem until now. Maybe I should find time to get around to putting the disconnect on the battery!

Lesson learned. Sometimes you just have to think outside of the box.

 

Disconnecting the battery will not kill the engine. The alternator will supply electrical power.

 

Does your car have power brakes or manual? If they are power brakes then the vacuum booster and / or the vacuum line, 90, and grommet are bad. I agree with above if it was the positive terminal but question it if it was the ground. I promise you fixing the brakes will make driving your car 1000 times more fun and you don't risk killing yourself.

 

If you were going downhill....the float in the carb may be set pretty high as I think vette quadrajets are. The gas might be flooding your engine and causing it to die....especially NOT on a level road...it can happen even on level ground.

That is my out of the box response....especially if it takes a some time to restart the engine via the starter.

68 Thunder is right on also.

 

Thanks guys. I'll bet your right, it may very well not be the battery. It was hard to start and cranked slow the second time. But I kind of blew that off because it's hard to start when it hot, but now that I think about it, it has to sit for 15 minutes or more before it's hard to start when hot. I think the fuel may be getting hot in the bowls. I might just lower the float level to see what that does for it. I could see the high float level causing an issue. This is a Holly though, not a Q-Jet, but same principal.

As far as the brakes, I'm probably going to do a body off soon and EVERYTHING is going to be replaced on the brakes and I'm only going to use the best stuff there.

 

Looking at the pic of your car you don't need a body off and just need to fix a few minor things and drive the hell out of it. It is nicer than mine i bet.

 

He might get a severe case of the "while I'm at its" when tending to his brakes... thereby causing the body to be separated from the frame.

The OP should have a case of his favorite cold barley pops nearby on that first day to ease the stress.

Doctors orders, you know.

 

I'm fairly **** about things, not Alan ****, but close. I've rebuild a few other small vehicles from the frame up and would love to do the vette. I just don't know if I could go a couple of years without driving it.

 

That is a very expensive diagnosis if there ever was one!!!

 

bump

 

Are you running a Holley double pumper? If so, your floats may be set too high. When you hit the brakes, fuel sloshes over causing the engine to flood out.

This is typical of Holleys and mine also did it until I lowered the floats a hair.

 

That's what I'm going to do. I think they are a bit on the high side.

 

I was going to agree with your diagnosis because the exact same thing happened to me.



http://forums.corvetteforum.com/1467596-post2.html

 

Isn't there a "horn" in the Hollys to prevent this? I've seen photos of them, but mine doesn't have one. It's a little plastic U-shaped piece towards the top of the bowl.

 

it's called a bowl vent but the floats still have to be correctly set
https://www.google.com/search?q=holl...w=1680&bih=849

 

Old racing rule, both feet out.

Be sure you step on the clutch, too, or you will kill the engine if you don't. (All Real Corvettes have a Clutch)

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Now to your spongy brakes, put it on jackstands.

Remove all four wheels.

Go to right rear and open one of the upper caliper bleeder screws. There should be no lower bleeder screws, it should be a plug. Observe air bubbles coming out. Do not let the master cylinder go dry. Pour brake fluid in SLOWLY to prevent making bubbles in reservoir.

When no air bubbles show for awhile, close bleeder.

Repeat with next top bleeder.

Repeat with left rear caliper.

Go to right front caliper. Open upper bleeder (only one). When no air bubbles come out after awhile, closed bleeder.

Repeat on left front caliper.

Put wheels on, and drive it. If mushy, get them warm to hot by braking often. Come back and repeat the bleeding process.

 

I'm gonna be a jerk here and ask why you drive around with your son in the car WITH SPONGY BRAKES? That is completely irresponsible of you. Never mind you are endangering other people on the road, but you are putting your son's life at risk too.

Park the car until you have a firm brake pedal and brakes good enough to lock all four tires. FIX IT!


Pete