C3 leaf spring install problems
Thread Starter
Cruising
Joined: Oct 2020
Posts: 12
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From: Thornton (north Denver) Colorado
C3 leaf spring install problems
Ok I have a problem. I went to remove my sagging 1977 c3 leaf spring. All bolts were rusted bad. When removing the two rear bolts on the center spring plate/support both broke the upper mounts! Still can’t get one of the front bolts out (any tricks). If and when I do, what is the repair for the rear bolt supports ??
am I screwed
thanks.
am I screwed
thanks.
Drifting
Joined: Nov 2013
Posts: 1,547
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From: Scottsdale Arizona
The rear bolt mounts that you’re talking about are bolted to the differential cover. Replacing the cover is your only option. I recently replaced the cover on my 68 and I removed the differential completely.
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2025 C3 of the Year Finalist - Modified
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Cruise-In VIII Veteran
I have a "Heavy Duty" cover on my car. Broken spring mounts are a common thing. Looks like your job just got a lot bigger. The joys of working on old cars. Out comes the diff.
Thread Starter
Cruising
Joined: Oct 2020
Posts: 12
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From: Thornton (north Denver) Colorado
Broken differential cover for leaf spring bolts
Darn that’s what I was afraid of. And all those bolts look really rusted. Getting to think this more than I can handle
Thread Starter
Cruising
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From: Thornton (north Denver) Colorado
Heavy duty cover
Thread Starter
Cruising
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From: Thornton (north Denver) Colorado
Le Mans Master
Joined: May 2002
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From: Lebanon Township New Jersey
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Le Mans Master
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From: mount holly NC
2025 c3 ('74-'82) of the Year Finalist - Unmodified
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If you decide to do this yourself attach the spring to the cover BUT only tighten the 4 bolts finger tight then attach each end spring bolt to the trailing are and install the wheels and lower the car onto ramps.
You can then tighten the 4 center bolts.
Too late to tell you now that you must have the car on ramps and then loosen the 4 center bolts first so as to not break the ears off of the differential cover
You can then tighten the 4 center bolts.
Too late to tell you now that you must have the car on ramps and then loosen the 4 center bolts first so as to not break the ears off of the differential cover
Race Director
Joined: Nov 2006
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From: Sunshine Coast, Queensland, Australia
2025 C3 of the Year Finalist - Modified
2024 C3 of the Year Finalist- Modified
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Cruise-In VIII Veteran
Yes, sad but true. A bit late for instruction on how to remove. But , Heavy Duty covers are available, and definitely NOT Aluminium.
Thread Starter
Cruising
Joined: Oct 2020
Posts: 12
Likes: 1
From: Thornton (north Denver) Colorado
Thread Starter
Cruising
Joined: Oct 2020
Posts: 12
Likes: 1
From: Thornton (north Denver) Colorado
Leaf Spring removal/install
If you decide to do this yourself attach the spring to the cover BUT only tighten the 4 bolts finger tight then attach each end spring bolt to the trailing are and install the wheels and lower the car onto ramps.
You can then tighten the 4 center bolts.
Too late to tell you now that you must have the car on ramps and then loosen the 4 center bolts first so as to not break the ears off of the differential cover
You can then tighten the 4 center bolts.
Too late to tell you now that you must have the car on ramps and then loosen the 4 center bolts first so as to not break the ears off of the differential cover
—————
So I just noticed it looks like the cover is attached to some sort of support running side to side. What’s that all about?
Last edited by Chrislp; Oct 29, 2020 at 07:30 PM. Reason: Question
2026 Loser of the Year
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From: New Or-leens Loo-z-anna
You can then use more rust blaster and then use an Easy-Out tool to unscrew the broken stud/bolt.
Thread Starter
Cruising
Joined: Oct 2020
Posts: 12
Likes: 1
From: Thornton (north Denver) Colorado
Thread Starter
Cruising
Joined: Oct 2020
Posts: 12
Likes: 1
From: Thornton (north Denver) Colorado
Broken differential
So for removal I had the car on jack stands and removed the two end spring bolts. Then went to take the 4 center bolts out. Not the right way I take it. And with three bolts removed I can’t get the forth one out yet. Am spraying the heck out of it and giving days to absorb. Then fingers crossed. Even though the cover has to be replaced anyway. THANKS for the info.
Le Mans Master
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From: Indiana
Thread Starter
Cruising
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From: Thornton (north Denver) Colorado
Pro
Joined: Mar 2007
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From: Austin TX area
Since it sounds like you will be working on you car more. I suggest you purchase the AIM (Assembly Instruction Manual) and the shop service manual for your year. Not a Hayes, the GM manual. Also, when you replace the spring and are torquing the center mounting plate bolts, make sure there is weight on the suspension. Otherwise you will bend the plate. Been there, done that. The vendors will be more than happy to sell you another one. You might want to put your location in you profile, there may be a member near you that can help you out. Good luck.
Had a 1976 L-82, 4-sp
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From: Some days your the dog and some days your the hydrant.
Royal Canadian Navy
The diff cover is bolted to the rear crossmember which is held by two bolts - left and right side. While supporting the differential with a jack of some sort, remove the two cross member bolts and separarte the crossmember from the fram on each side with a crowbar or similar. Lower assembly to ground and then remove the upper diff mounting bolts from the top of the cross member. Now you can remove the diff cover and replace. The above removal method is straight forward but labour intensive. You can do it!
Le Mans Master
Joined: May 2002
Posts: 5,086
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From: Lebanon Township New Jersey
The diff cover is bolted to the rear crossmember which is held by two bolts - left and right side. While supporting the differential with a jack of some sort, remove the two cross member bolts and separarte the crossmember from the fram on each side with a crowbar or similar. Lower assembly to ground and then remove the upper diff mounting bolts from the top of the cross member. Now you can remove the diff cover and replace. The above removal method is straight forward but labour intensive. You can do it!