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Old 08-17-2014, 10:20 AM   #1
DJette
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Default Now that I look at it there's not much point in asking,but...

Hello all, new owner here and hopefully soon to be a frequent forum member. I recently purchased a 77 for pennies on the dollar and am sorting out all the wonderful problems that come with a pennies on the dollar purchase. The car sat for at least 15 and is in surprisingly good shape, but there's one thing that has me worried. There's a crack in the diff cover where the leaf spring mounts. I had been worried it was part of the subframe or something irreplaceable. Well I took a good look at it this morning and much to my relief it is, but yay gear oil. Combine me not having any experience with rear ends and the smell of gear oil making me want to vomit... Not looking forward to this endeavor. Pic of the crack here http://imgur.com/KBUzuZ2

Any tips or things I should look for when I dive in? Also, I assume I can't drive the car because I also assume should it break it would be catastrophic.

I have a slew of questions bouncing around in my head, but I'm going to tackle this one piece at a time.
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Old 08-17-2014, 11:00 AM   #2
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Look around for a used rear end setup and replace that old one. By the time you get around to cleaning it up, finding a reputable welder, etc, you will be better off replacing it. Im going to warn you now, if that car sat for 15 years, you are going to wind up replacing EVERYTHING back there, including the trailing arm bushings, the brake calipers, all the bushings, probably even the main spring. As you stated, your pennies on the dollar purchase is going to turn into a dollars on the penny project. Good luck.
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Old 08-17-2014, 11:13 AM   #3
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Already planning on neoprene body mounts and suspension bushings. The rear leaf is SHOT, kind of a shame as it's a 9 leaf. The steel brake line is rusted out along the frame so I was thinking about doing the two front calipers for the remainder of the test n tune period.
The car runs great and so far all I've done is fuel lines and put in a new fuel pump. The four barrel isn't opening, but I'm going to get stopping and saftey dialed in first.
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Old 08-17-2014, 11:24 AM   #4
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You need take the differential out and replace the cover.
http://www.muskegonbrake.com/corvett...erential-cover
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Old 08-17-2014, 11:24 AM   #5
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Quote:
Originally Posted by DJette View Post
Hello all, new owner here and hopefully soon to be a frequent forum member. I recently purchased a 77 for pennies on the dollar and am sorting out all the wonderful problems that come with a pennies on the dollar purchase. The car sat for at least 15 and is in surprisingly good shape, but there's one thing that has me worried. There's a crack in the diff cover where the leaf spring mounts. I had been worried it was part of the subframe or something irreplaceable. Well I took a good look at it this morning and much to my relief it is, but yay gear oil. Combine me not having any experience with rear ends and the smell of gear oil making me want to vomit... Not looking forward to this endeavor. Pic of the crack here http://imgur.com/KBUzuZ2

Any tips or things I should look for when I dive in? Also, I assume I can't drive the car because I also assume should it break it would be catastrophic.

I have a slew of questions bouncing around in my head, but I'm going to tackle this one piece at a time.

That's not a big problem to fix. Happens often, all you need is a new rear end cover. If your going to replace other items then this the time to do it. Be sure when you tighten the spring bolts have the weight of the car on the tires to flatten out the spring because you will break the new cover too if you don't.
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Old 08-17-2014, 11:25 AM   #6
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Quote:
Originally Posted by DJette View Post
Already planning on neoprene body mounts and suspension bushings.
Bad idea. Poly is about the dumbest idea ever introduced for bushings.

The cracked diff cover is very common, the damage being caused by Bubba tightening the spring bolts while the car is up in the air. Why do you think your spring is shot?
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Old 08-17-2014, 11:27 AM   #7
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Quote:
Originally Posted by DJette View Post
Already planning on neoprene body mounts and suspension bushings. The rear leaf is SHOT, kind of a shame as it's a 9 leaf. The steel brake line is rusted out along the frame so I was thinking about doing the two front calipers for the remainder of the test n tune period.
The car runs great and so far all I've done is fuel lines and put in a new fuel pump. The four barrel isn't opening, but I'm going to get stopping and saftey dialed in first.
My 73 sat for 18 years under a car port.. I also got mine for almost nothing but soon found out that the Interior parts cost are out of this world.. LOL but it will look and smell like a new car. I also understand I will not get my investment back. I just enjoy bring back a car from near death.

Are you taking your body off the frame? If so thats when you want to tackle the break lines.

Tim
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Old 08-17-2014, 11:38 AM   #8
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Bad idea. Poly is about the dumbest idea ever introduced for bushings.

The cracked diff cover is very common, the damage being caused by Bubba tightening the spring bolts while the car is up in the air. Why do you think your spring is shot?
The rear of the car slightly lower than the front and has a very bad ride. Although I get the feeling that was a rhetorical question aimed at bubba. What's so bad about poly? My daily driver has poly everywhere and I love it.

Quote:
Originally Posted by Tim 1973 View Post
My 73 sat for 18 years under a car port.. I also got mine for almost nothing but soon found out that the Interior parts cost are out of this world.. LOL but it will look and smell like a new car. I also understand I will not get my investment back. I just enjoy bring back a car from near death.

Are you taking your body off the frame? If so thats when you want to tackle the break lines.

Tim
I don't plan on taking the body off. I would like to, but it sounds like a lot more work than is worth it at this point in time.

Quote:
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You need take the differential out and replace the cover.
http://www.muskegonbrake.com/corvett...erential-cover
Thank you!
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Old 08-17-2014, 11:42 AM   #9
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A new heavy duty (which a lot of people switch to) differential cover and gasket will run about $150, versus a whole rebuilt diff to swap out will be $900ish. Might as well change the spring while you're there. I have a 330 pound fiberglass Monospring and really like it.

These cars do require work (sometimes constant work) but I think they are worth it! If you do things yourself you will get to know your own car better.

When I first got mine, I would inspect it with a bright flashlight from head to toe before and after each ride, engine on and off. (Still do this usually.)
This way I can keep an eye on what needs to be fixed now versus later. By choosing what to rebuild versus swap (to save time) versus repair, I can keep driving my Vette every week like I like.

Have fun and be safe, do NOT scrimp on the shop equipment that supports the car when it's over your head.
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My C3 is not leaking, it just likes to mark its territory!
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Old 08-17-2014, 11:46 AM   #10
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What's so bad about poly? My daily driver has poly everywhere and I love it.
If you like a marked increase in harshness and very little or no improvement in handling, go for it.
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Old 08-17-2014, 12:45 PM   #11
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Quote:
Originally Posted by Mike Ward View Post
If you like a marked increase in harshness and very little or no improvement in handling, go for it.


Poly bushings are an upgrade only as a balanced planned upgrade to make the suspension much firmer for on track use. And only should be considered with other modifications like coil over shocks, etc..

Just go with new stock bushings to bring the ride to comfortable stock street ride unless tracking it.
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Old 08-17-2014, 12:55 PM   #12
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Quote:
Originally Posted by DJette View Post
Already planning on neoprene body mounts and suspension bushings. The rear leaf is SHOT, kind of a shame as it's a 9 leaf. The steel brake line is rusted out along the frame so I was thinking about doing the two front calipers for the remainder of the test n tune period.
The car runs great and so far all I've done is fuel lines and put in a new fuel pump. The four barrel isn't opening, but I'm going to get stopping and saftey dialed in first.
9 leaf springs are the base leaf spring and offer very nice ride quality, obviously at the expense of handling.

If you intend to replace it with a more aggressive spring (like the 330# monospring suggested in the thread), you should balance the upgrade with a firmer front spring. Cars with the base suspension ride VERY smoothly though. Also, going with a fiberglass spring will necessitate a shock upgrade to handle it. KYB GR2s valved for fiberglass at a minimum. I highly recommend Bilstein sports.

As to your issue with the carburetor, which carb is it and why do you think the secondaries are not operating?
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Old 08-17-2014, 12:55 PM   #13
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Quote:
Originally Posted by minitech View Post


Poly bushings are an upgrade only as a balanced planned upgrade to make the suspension much firmer for on track use. And only should be considered with other modifications like coil over shocks, etc..

Just go with new stock bushings to bring the ride to comfortable stock street ride unless tracking it.
It's going to be tracked. Friend of mine has a 280z he likes to brag about all the time and I would like to show him America can turn too
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Old 08-17-2014, 03:12 PM   #14
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So you are the guy that got beat by a Datsun Z-car in another thread recently. How can you let that happen? U gotta' represent yo.

Last edited by persuader; 08-17-2014 at 03:14 PM.
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Old 08-17-2014, 03:28 PM   #15
DJette
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Nope, I haven't had the chance to lose to a dirty datsun yet. I've only had my Vette a month and haven't even been able to drive it. It doesn't even have seat belts right now! I probably won't be track ready till spring time if then.

Actually, I did put 50 miles on it Wednesday... Not my smartest decision.... But I finally got to drive it!
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Old 08-17-2014, 03:52 PM   #16
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Hate to say it but I had a few of the older datsuns, 1971 240z and a 1977 280z and they were much easier to drive fast thru the turns. I think the 240 was only about 2400 pounds. If both cars are close to stock it will come down to who is the better driver. Just my 2 cents. Either way it will be a lot of fun at the track with friends.
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Old 08-17-2014, 04:45 PM   #17
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Quote:
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It's going to be tracked. Friend of mine has a 280z he likes to brag about all the time and I would like to show him America can turn too
Great! If you have not been on a track it is best to fine a HPDE driving school, they travel to different tracks. Spend a 3 day event with them first then you get to make the most of your car on the track and be safer. You could hang out at a track if local and get to know the guys there. There will be some instructor types there that can give you a ride and help with your can. Get a car racing rated helmet.
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Old 08-17-2014, 04:49 PM   #18
DJette
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Great! If you have not been on a track it is best to fine a HPDE driving school, they travel to different tracks. Spend a 3 day event with them first then you get to make the most of your car on the track and be safer. You could hang out at a track if local and get to know the guys there. There will be some instructor types there that can give you a ride and help with your can. Get a car racing rated helmet.
I already have a fire suit, shoes, kneck brace, and helmet. Been chump racing for a few years now and since my dad and I do body work for the KC Cobra Club I autocross with them from time to time

Despite my age and relatively low track time I'm one hell of a driver.
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Old 08-17-2014, 06:02 PM   #19
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Good to know you think you can drive. I don't see an answer to my question about the carburetor.
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Old 08-17-2014, 06:06 PM   #20
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I like the smell of gear oil
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Old 08-17-2014, 06:06 PM
 
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