'70-'72 Chrome Bumper Bolt Size

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Aug 19, 2015 | 11:28 AM

Kubs

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Le Mans Master

Joined: Oct 2007

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From: Akron Ohio

2025 Corvette of the Year Finalist - Modified

2024 C5 of the Year Winner - Modified

2023 C5 of the Year Finalist - Modified

2022 C5 of the Year Finalist - Modified

St. Jude Donor '09-'10-'11

'70-'72 Chrome Bumper Bolt Size

Hi guys,

I just purchased a '71 project car. I have a C4 racecar so I am usually over in one of those sections, but new over here.

I went to test fit the bumpers back on, but seem to be missing some hardware. The bolts I do have for the front look to be 7/16" but I was wondering if someone knew exact lengths and sizes front and rear (I don't have any rear bolts) so I can buy some stainless replacements.

Aug 19, 2015 | 01:04 PM

Kubs

Thread Starter

Le Mans Master

Joined: Oct 2007

Posts: 9,680

Likes: 3,427

From: Akron Ohio

2025 Corvette of the Year Finalist - Modified

2024 C5 of the Year Winner - Modified

2023 C5 of the Year Finalist - Modified

2022 C5 of the Year Finalist - Modified

St. Jude Donor '09-'10-'11

So based on the few bolts I have and some kits I have seen online, it looks like I need mostly 7/16-14 x 1.5" but the front kits have 2 longer bolts. Anyone know what those ones are for and how much longer they are?

Aug 19, 2015 | 01:14 PM

garyguinn

Burning Brakes

Joined: Sep 2007

Posts: 802

Likes: 69

From: Tulsa Ok

Bumper bolts

here is what I have come up with..
doesn't mean its completely correct, but works well for me

I use stainless bolts and hardware

7/16-14 x 1 1/4 hex cap screw 18-8 stainless steel
7/16 split lockwasher, stainless steel
7/16 x 1 1/8 od flat washer, stainless steel
7/16-14 finished hex nut, stainless steel

3/8 -16 x 2 hex cap screw stainless steel

1/2 -13 x 1 1/2 hex cap screw stainless steel
1/2 -13 finished hex nut, stainless steel

5/16-18 x 1 1/2 hex cap screw stainless steel
5/16 x 3/4 od flat washer stainless steel
5/16-24 x 1/2 hex cap screw stainless steel

Aug 19, 2015 | 01:25 PM

Revi

Drifting

Joined: Oct 2005

Posts: 1,615

Likes: 150

From: Forth Worth TX

You should pick up a 1971 A.I.M., it will have everything you need to know.

Aug 19, 2015 | 02:33 PM

Kubs

Thread Starter

Le Mans Master

Joined: Oct 2007

Posts: 9,680

Likes: 3,427

From: Akron Ohio

2025 Corvette of the Year Finalist - Modified

2024 C5 of the Year Winner - Modified

2023 C5 of the Year Finalist - Modified

2022 C5 of the Year Finalist - Modified

St. Jude Donor '09-'10-'11

Thanks! I have added some notes.

Quote:

Originally Posted by garyguinn

here is what I have come up with..
doesn't mean its completely correct, but works well for me

I use stainless bolts and hardware

7/16-14 x 1 1/4 hex cap screw 18-8 stainless steel
7/16 split lockwasher, stainless steel
7/16 x 1 1/8 od flat washer, stainless steel
7/16-14 finished hex nut, stainless steel
^^Front? QTY 6?

3/8 -16 x 2 hex cap screw stainless steel
I dont have any of these, where do they go? How many?

1/2 -13 x 1 1/2 hex cap screw stainless steel
1/2 -13 finished hex nut, stainless steel
^Rear? How many?

5/16-18 x 1 1/2 hex cap screw stainless steel
5/16 x 3/4 od flat washer stainless steel
5/16-24 x 1/2 hex cap screw stainless steel
^Rear as well?

Quote:

Originally Posted by Revi

You should pick up a 1971 A.I.M., it will have everything you need to know.

What is an AIM? Where can I get one?

Thanks guys!

Aug 19, 2015 | 03:49 PM

jnb5101

Le Mans Master

Joined: Jul 2006

Posts: 8,117

Likes: 104

From: charlotte north carolina

From the Parts and Illustration Catalog

Aug 19, 2015 | 04:18 PM

Kubs

Thread Starter

Le Mans Master

Joined: Oct 2007

Posts: 9,680

Likes: 3,427

From: Akron Ohio

2025 Corvette of the Year Finalist - Modified

2024 C5 of the Year Winner - Modified

2023 C5 of the Year Finalist - Modified

2022 C5 of the Year Finalist - Modified

St. Jude Donor '09-'10-'11

Quote:

Originally Posted by jnb5101

From the Parts and Illustration Catalog

Awesome! Thanks! Got a rear one too?

Aug 19, 2015 | 04:49 PM

Revi

Drifting

Joined: Oct 2005

Posts: 1,615

Likes: 150

From: Forth Worth TX

Quote:

Originally Posted by Kubs

What is an AIM? Where can I get one?

Thanks guys!

The A.I.M. is the Assembly Instruction Manual. It is what the workers used on the assembly line. They are year specific (71) and just about every Corvette parts vendor sells them.

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Aug 19, 2015 | 05:54 PM

Alan 71

Team Owner

Joined: Sep 2006

Posts: 31,160

Likes: 4,236

From: Westminster Maryland

Hi K,
While there's no doubt that the Assembly Instruction Manual is the most valuable piece of information about our cars we have, it doesn't give bolt sizes, just where they're used and what their part number was.
The Illustrated Parts Catalogue is probably the best single source for bolt sizes; it has many, many, listed, but not all.
So I'd say buy both, (AIM & IPC), PLUS the GM 71 Chassis Service Manual if you're going to be working on your 71.
Regards,
Alan

Aug 19, 2015 | 06:06 PM

#10

Kubs

Thread Starter

Le Mans Master

Joined: Oct 2007

Posts: 9,680

Likes: 3,427

From: Akron Ohio

2025 Corvette of the Year Finalist - Modified

2024 C5 of the Year Winner - Modified

2023 C5 of the Year Finalist - Modified

2022 C5 of the Year Finalist - Modified

St. Jude Donor '09-'10-'11

Quote:

Originally Posted by Revi

The A.I.M. is the Assembly Instruction Manual. It is what the workers used on the assembly line. They are year specific (71) and just about every Corvette parts vendor sells them.

So the previous owner left a stack of books in the car. I thought there were all just Chilton's manuals and crap like that, but one was a 3 ring Rigid tools binder. Turns out, the AIM is inside it! Dummy me, I should have checked it out first.

Here are the front and rear assemblies for reference:

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