MI Still looking spare tire mounting bolt. - The 1947 - Present Chevrolet & GMC Truck Message Board Network

terry b · 03-18-2019, 12:07 PM

Need the carriage bolt that holds the tire to the in the bed spare tire carrier for a 1972 C-20 3/4 truck. OEM only. 1/2"20 x 8" long. GM#3898396.

terry b · 03-21-2019, 11:31 AM

Still looking!

bill3rail · 03-21-2019, 01:27 PM

Quote:

Originally Posted by terry b

Need the carriage bolt that holds the tire to the in the bed spare tire carrier for a 1972 C-20 3/4 truck. OEM only. 1/2"20 x 8" long. GM#3898396.

Is it 1/2"-20 or 7/16" thread?
For some reason I thought it was 7/16, but I am often wrong ask my wife!

Bill

terry b · 03-21-2019, 01:58 PM

Hey Bill. 7/16 on the 1/2 ton. 1/2 on the 3/4-1 ton. Thanks for looking. If you know of one i would be happy to give a finder's fee. ��

bill3rail · 03-21-2019, 02:01 PM

Quote:

Originally Posted by terry b

Hey Bill. 7/16 on the 1/2 ton. 1/2 on the 3/4-1 ton. Thanks for looking. If you know of one i would be happy to give a finder's fee. ��

OK, that was my misteak! I have a 1/2 ton. I was considering having them made for my truck. If I find any, I will let you know.

Bill

terry b · 03-21-2019, 02:07 PM

Good luck! I have seen a few 7/16 in the past come thru but never the 1/2. May go the hardware store bolt and thread it further down the stem to match the OEM bolt but the thread count will be wrong.

bill3rail · 03-21-2019, 02:51 PM

Hardware supply house near me can not order 7/16" or 1/2" fine thread.

https://www.fastenere.com/

Trailer spare tire carriers have 7/16-20 threads so I may just make one for my needs.

Bill

bill3rail · 03-21-2019, 02:52 PM

Like these...

**hooverfish** · 03-21-2019, 03:29 PM

This one sold on Ebay march 17, P/N 3991022, so maybe keep watching there.
My parts book says this is correct for 67-72 series 10 thru 30.
GMWikiparts says it is correct for additional years too, even some Corvettes.
https://www.ebay.com/itm/1955-1977-C...p2047675.l2557

bill3rail · 03-21-2019, 03:40 PM

Quote:

Originally Posted by hooverfish

This one sold on Ebay march 17, P/N 3991022, so maybe keep watching there.
My parts book says this is correct for 67-72 series 10 thru 30.
GMWikiparts says it is correct for additional years too, even some Corvettes.
https://www.ebay.com/itm/1955-1977-C...p2047675.l2557

Auction states that was 1/2"-13.

Bill

**hooverfish** · 03-21-2019, 03:52 PM

Quote:

Originally Posted by bill3rail

Auction states that was 1/2"-13.

Bill

So is it for 3/4 ton only? Parts book says it fits both 1/2T and 3/4T.
Or were you making a different point?
Maybe this one is for under the bed instead of side/bed mount ?

BLT gmc · 03-21-2019, 04:27 PM

Send a PM to member. 71K5Randy. He has made these, but I can't remember the thread size. Bruce

terry b · 03-21-2019, 04:48 PM

From what i have found 1/2" 2 0 threads per inch by eight and one eights inch long GM part number 3898396 is three quarter and one ton in the bed carriage bolt.

**Stocker** · 03-21-2019, 04:57 PM

Quote:

Originally Posted by BLT gmc

Send a PM to member. 71K5Randy. He has made these, but I can't remember the thread size. Bruce

Those were for Blazers.... carriage bolts, GM 3991023, 6-7/8” length, fine thread 7/16"-20.

http://67-72chevytrucks.com/vboard/s...d.php?t=760950

BLT gmc · 03-21-2019, 05:23 PM

http://67-72chevytrucks.com/vboard/s...ight=71K5Randy

This is the thread with the re po info.

PN and photos included! Reference to the factory parts manual.

I just read the above thread, these are for Blazers and 4x4. Thank you for clarification.

**Canuckvetter** · 03-21-2019, 11:53 PM

For reference 7/16" & 1/2"

http://67-72chevytrucks.com/vboard/a...1&d=1553226717

03-18-2019, 12:07 PM	#1
terry b Registered User Join Date: Oct 2011 Location: jackson michigan Posts: 755	Still looking spare tire mounting bolt. Need the carriage bolt that holds the tire to the in the bed spare tire carrier for a 1972 C-20 3/4 truck. OEM only. 1/2"20 x 8" long. GM#3898396.

03-21-2019, 11:31 AM	#2
terry b Registered User Join Date: Oct 2011 Location: jackson michigan Posts: 755	Re: Still looking spare tire mounting bolt. Still looking!

03-21-2019, 01:58 PM	#4
terry b Registered User Join Date: Oct 2011 Location: jackson michigan Posts: 755	Re: Still looking spare tire mounting bolt. Hey Bill. 7/16 on the 1/2 ton. 1/2 on the 3/4-1 ton. Thanks for looking. If you know of one i would be happy to give a finder's fee. �� Last edited by terry b; 03-21-2019 at 02:00 PM. Reason: Changes

03-21-2019, 02:07 PM	#6
terry b Registered User Join Date: Oct 2011 Location: jackson michigan Posts: 755	Re: Still looking spare tire mounting bolt. Good luck! I have seen a few 7/16 in the past come thru but never the 1/2. May go the hardware store bolt and thread it further down the stem to match the OEM bolt but the thread count will be wrong. Last edited by terry b; 03-21-2019 at 02:09 PM. Reason: Spelling

03-21-2019, 02:51 PM	#7
bill3rail Registered User Join Date: Jul 2013 Location: LI, NY 11801 Posts: 1,140	Re: Still looking spare tire mounting bolt. Hardware supply house near me can not order 7/16" or 1/2" fine thread. https://www.fastenere.com/ Trailer spare tire carriers have 7/16-20 threads so I may just make one for my needs. Bill __________________ 1970 C10 8' Fleetside, L6 250, 3 on the Tree. The most basic of pickup trucks!

03-21-2019, 02:52 PM	#8
bill3rail Registered User Join Date: Jul 2013 Location: LI, NY 11801 Posts: 1,140	Re: Still looking spare tire mounting bolt. Like these... __________________ 1970 C10 8' Fleetside, L6 250, 3 on the Tree. The most basic of pickup trucks!

03-21-2019, 03:29 PM	#9
hooverfish Senior Member Join Date: Oct 2012 Location: Lexington, Ky Posts: 2,147	Re: Still looking spare tire mounting bolt. This one sold on Ebay march 17, P/N 3991022, so maybe keep watching there. My parts book says this is correct for 67-72 series 10 thru 30. GMWikiparts says it is correct for additional years too, even some Corvettes. https://www.ebay.com/itm/1955-1977-C...p2047675.l2557 __________________ Larry 84 Chevy SWB, "Roy", dark blue OG paint, 5.7 LS1, 4L60, Vintage Air, 96k miles. "It's a sorry man who can't find his wife a good job"

03-21-2019, 04:27 PM	#12
BLT gmc Registered User Join Date: Feb 2014 Location: West Iowa Posts: 1,106	Re: Still looking spare tire mounting bolt. Send a PM to member. 71K5Randy. He has made these, but I can't remember the thread size. Bruce

03-21-2019, 04:48 PM	#13
terry b Registered User Join Date: Oct 2011 Location: jackson michigan Posts: 755	Re: Still looking spare tire mounting bolt. From what i have found 1/2" 2 0 threads per inch by eight and one eights inch long GM part number 3898396 is three quarter and one ton in the bed carriage bolt.

03-21-2019, 05:23 PM	#15
BLT gmc Registered User Join Date: Feb 2014 Location: West Iowa Posts: 1,106	Re: Still looking spare tire mounting bolt. http://67-72chevytrucks.com/vboard/s...ight=71K5Randy This is the thread with the re po info. PN and photos included! Reference to the factory parts manual. I just read the above thread, these are for Blazers and 4x4. Thank you for clarification. Last edited by BLT gmc; 03-21-2019 at 05:29 PM.

03-21-2019, 11:53 PM	#16
Canuckvetter How did I get this OLD! Join Date: Dec 2014 Location: Lamont County, AB, CANADA Posts: 1,050	Re: Still looking spare tire mounting bolt. For reference 7/16" & 1/2" http://67-72chevytrucks.com/vboard/a...1&d=1553226717 Attached Images __________________ 1967 Oshawa built LWB Fleetside. 327,3 OTT, 515 Vermilion, CST, PS, PB, Shoulder Harness, Tach,Vac, Speed Warning, Choke Delete, Manual Throttle, Fawn interior. Dealer installed A/C 04/2015, N34 Rosewood Wheel 06/2023 Members who I have met personally. Metaldoc, chevnkevin, 62 Longbed, 72LHorn, 72MARIO, YBNORML, TBONE1964, Classic Bowties, Chevemall, Dagnabbitt.



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