Just bought a Vette, need help!

[OneHotV6]

I don't have time to do a search for all of these so I will list them and see who can give me some good answers. I just bought a '70 coupe and found some problems that need to be fixed..

- Tach is dead
- Car runs rough and stalls sometimes
- Brake peddle goes down almost to floor before the brakes work
- After shutting the car off, there's a hissing sound coming from under the dash
- Inside door lock is broken, guy said it needs a spring to hold the lock on...
- Guy also mentioned there's a factory alarm but there's no key thing in the back and can't figure out if there actually is one or if it works..

Thanks in advance..!

 

[Johan]

Congratulations to the new Vette!

I think you can find the answer to most questions in previous posts. It is for sure much quicker do do a search, than for people to write their long posts again...

Anyway, if we start with the tach:
A cable to your tach is connected to the distributor. Unscrew this (with your fingers), and you should be able to see a "needle" on the cable end, that goes into the distributor. Spin this needle with fingers and have someone look at the tach in the car. If the tach doesent move, the cable is broken (or the actual tach needle is loose or something).
If the needle moves, then the problem is in the distributor, propably in the tach drive cross gear (this happened to me). Theese gears wear out. You might be able to remove the cross gear from the distributor with the distributor still in car, to examine the gears, but if they are worn you must propably change the distributor main shaft anyway, so you might just pull the distributor in the first place.

 

[ChuckG]

I think the key for the factory alarm on 70 and up Corvettes is on the drivers front fender, above the "egg crate" grills. Chuck

 

[Tom73]

I think the key for the factory alarm on 70 and up Corvettes is on the drivers front fender, above the "egg crate" grills. Chuck

Nope, the fender business started in '74 with the rubber rear bumper.

The 70 would have a key on the rear between the tail lights if it had the factory alarm. Maybe the key hole has been glassed over or maybe it is an aftermarket alarm?

The hissing is more then likely a vacumn leak. Do the headlight open okay? The vacumn line run to an override switch at the base of the dash under the steering column.

tom...

 

[jim coulter]

The keyed switch for the alarm on a 71 is center rear above the word corvette. T would think the 70 would be also, since they are so similar. And congrats on your purchase.

 

[OneHotV6]

The car was repainted and there's no markings so the alarm system could've been removed.. that's great because I HATE alarm systems!! They're useless and annoying. The hissing sound does appear to be coming from under the dash where the switches are. I haven't tried using the lights yet, that's tomorrow's adventure. If I try to use the wipers and the leak is actually coming from that, how can shut the wipers off without breaking them under the cover?

Thanks for all the positive words, I need them right about now!!

 

[70Coupe]

Congrats on your '70! The black knob between the vacuum overrides for the wiper door and headlights under the dash is the wiper override...turn it and the wiper arms will not come up when the door opens. My '70 also ran rough and stalled in the beginning...turned out the carb was in desperate need of a rebuild.

 

[singledad_9]

Congrads on your car... PS, you might want to consider a different name for yourself as that you now own a V8.

Hissing sound from the dash sounds like your light switch vacum hose might be leaking. If memory serves, your lights are brought up via a vacum. There might be a leak there. There may be a rubber hose attached to your light switch that is old and dried out.

Brakes are simple, bleed them starting from the furthest point (ie: passenger side rear) and work your way forward. Replace with DOT 3 brake fluid. If still bad, you will need to either rebuild or replace your master cylinder. With a 6 pack or two, it's a nice weekend job. With 3 or 4 packs, you can stretch it out even longer.

As far as the engine running rough, my bet is that your car hasn't been cared for, for a period of time. A good tune up, plugs, points rotor and cap are in order. Secondly, check for vacum leaks around the intake and carb. Also check to make sure that the hoses are air tight. Make sure there is a hose on every connection or the connection is plugged. Finally, if all else fails, time to replace the carb gasket, if that doesn't work, intake.

If it were my car, I would focus my attention to first safety... Brakes, lights, seat belt, signal lights, etc. Then to driveability, engine tuneup, tires, alignment, shocks, etc. Then focus on comfort, door lock spring, etc. Echlers, ZIP, Contempory Vettes (vette junk yard) are good sources for both information and parts you will need to outfit your car, how you like.

Again congrads on your new car and good luck.

Don't forget to wave

Mike

 

[cwerve74]

I am 6 weeks into my 74 conv. I also have a list. The one item that was the same on yours & my car was brakes. I started with that item. This is what I found and my guess is yours will be the same. When you bleed the brakes you will find one wheel with lots of air. After you bleed it, the brakes will seem good. Be careful. You may have only masked the real problem. On mine after 100 or so miles had the same problem Brake pedal almost to the floor. This was a frighting moment Freeway ramp with short exit. The real problem with the wheel that has the air is a problem called Cavitation due to large runout of the disk rotor or wheel hub. Seems to be common on vetts of that age and year range. What is happening is-- due to being out of round the disk moves in and out inside the caplipar and causes air to be sucked under the seals of the calipar pistons. As little as .010 inch is enough. On mine you could not see it but putting your finger on top of the calipar next to the brake pad and rotate the disk you can feel it. If you have a dial indicator you can measure it. How to fix. 1) get rotor ture. This need to be done while the rotor is monuted on the car since the hub may be the issue. If your calipars are being replaced get StanlessSteel sleeves and O-Ring seals. The orginal lip seals are part of the problem. I collected this information with some amount of research but then a fighting momet will do that motivate you. I have lots of back up material if you would like.

 

[OneHotV6]

At this point, the brakes are my main concern. I have receipts from the guy and the motor was totally rebuilt a few years ago so it is most likely the vacuum leak and a badly needed tune-up or carb. I did have plans before I got the car to go with an Edlebrock carb and intake so it's not a big deal if it is the carb that's shot.

Thanks everyone for all the help so far, to me it seems like an uphill climb but with the help it is seeming easier.

CWERVE74: I'd appreciate any info you have so I can get the right parts and not have to worry later.

To anyone else: if there is anyone in the NY area that would like to help me out with any work please let me know, beers and pizza will be on me!

 

[jimbucks]

I have a 1969 350/350 I've owned for 15 years and have had many of these same problems. Here is what I had to fix:

- Tach is dead
The distributor has a drive gear on it which can go bad. Your cable may also be disconnected.

- Car runs rough and stalls sometimes
Suggest new points/plugs/wires. If it is still rough you may need carb work and or a new distributor. Hopefully this will take care of it.

- Brake peddle goes down almost to floor before the brakes work
I thought this was a master cylinder problem on my car. After replacing the master cylinder 3 times (and replacing the brake calipers with SS), it turned out I needed a new brake power booster. If you have power brakes and a new master cylinder doesn't do the trick, you probably need a new power booster. My brake problem frustrated me for almost 10 years until I figured out the cure. Should you need to install a power booster, the manual (at least the one I have) says to remove the dash -- DO NOT REMOVE THE DASH!!! The power booster can be installed without dash removal.

- After shutting the car off, there's a hissing sound coming from
under the dash
This could be related to the problem above if the power booster is bad. On the other hand, this may just be the way these cars are -- I still hear occassional hissing upon engine turn off.

- Inside door lock is broken, guy said it needs a spring to hold the lock on...
Don't know about this.

- Guy also mentioned there's a factory alarm but there's no key thing in the back and can't figure out if there actually is one or if it works..
Don't know about this.

Enjoy your car, and good luck.

 

[AUSSIEVETTEMAN]

I agree with Jimbucks

The hissing sound you can here under the dash is more likely to be a vacuum leak from your brake booster.
I have just had the same problem with my 81 Coupe here in Australia.
I would also check that master cylinder and repair or replace it if it is cactus. It may just need a flush and new fluid. This should be done every couple of years anyway.
You will be rewarded though, if you fix everything. Once we did the booster, the brakes nearly put me through the windscreen!

Oh, and a carby tune probably wouldn't go astray to get your baby running right again. As for Jimbucks suggestion about plugs, maybe consider NGK Iridium plugs. These are long life and have a self cleaning tip that doesn't carbon up. Of course there may be better ones out there, but these are the one my mad Corvette mechanic swears by. Couldn't hurt anyway.

Good luck and happy Vetting!

Cheers

Tony

 

[AUSSIEVETTEMAN]

Oh, just thought of something else.

We had an electrical miss fire the other day when driving back from an Indy event here on the Gold Coast.
I found a crack in the insulation on my plug leads. I am pretty sire that this was the cause.

Jimbucks would be right in his suggestion about plug leads as well.

Cheers

Tony

 

[cwerve74]

Here are the referenced documentation on Brake runout. Thnaks to the orginal poster.

Hib Halverson
Technical Writer for Internet & Print Media


http://www.idavette.net/hib/BBfHInet12.htm
and
http://www.idavette.net/hib/BBfHInet13.htm

 

[EVIL_GRIM]

i have somewhat of a rough idle too and my Baby would accelerate like $h1t *not an even acceleration*. My dad owns a 70' vette also, he recomended i use a product from Amsoil called..i think it was Amsoil P.I. The Performance Improver Gasoline Additive. it really helps your mpg,idle,acceleration, and when u kick it into 4-Barrel....every little pony in the engine feels there. :BOW

it might not even be that, but use that stuff anyways, trust me, you will worship this product like i do now. :BOW :BOW

 

[Eddie 70]

Congrats on the purchase of your 70. On the door lock problem. If I understand correctly, your door lock isn't staying put correctly. It needs a spring to hold it in place. Take a look at the picture and see the U shaped pieces, these are what hold the door lock in place. You need one of these to hold your door lock in place. I hope I am correct in my understanding of your problem.

 

[OneHotV6]

It's actually the inside lock, the knob doesn't stay on but there's a clip inside the knob but don't know how it goes on..

Overall update on the car is it's at my mechanics shop to get a complete checkup and see what it needs, although when I opened up the air cleaner, to my surprise there was no air filter.. Now I can just image what else can be wrong! I hate people that don't take care of cars.. especially these!!!!!!!