Rear seat question - The 1947 - Present Chevrolet & GMC Truck Message Board Network

teamharvey · 04-24-2005, 10:02 PM

Anyone know what size/length bolts are needed to install rear seat ? Are front hold down bolts the same size as the rear bracket bolts ?

Thanks,
Bret

BobbyK · 04-25-2005, 01:22 AM

I think they are 7/16th x 1" or 1.25"

71jimmy · 04-25-2005, 01:11 PM

I just sized mine in prep for the rear seat install. Don't know if this is "factory" correct or not because I don't have the original bolts. Used a tap to clean the threads and this is what I found: rear of seat bolts = 1/2 (13) and front rear seat bolts 7/16 (14). After guesstimating for washers and thickness of seat brackets/clamps this is what I bought at a hardware store, all grade 8: four 1/2x1-1/2x13 with a flat washer and lock washer for the rear, and two 7/16x 1 -1/4x14 with flat and lock washer for front of rear seat.

teamharvey · 04-25-2005, 06:58 PM

Thanks !

bouncytruck · 04-25-2005, 07:08 PM

As long as we are on the subject, the mounting "holes" for the front brackets in my '69 Blazer are different than they are in my '72. The front location doesn't have a hole that goes completely throught the bed. There are some sort of "threads" on the reinforcing piece welded to the floor, similar to a speed nut. I have yet to figure out what size bolt to use there.

Anyone else have the same thing? The rear seat is listed on the glove box.

teamharvey · 04-26-2005, 11:27 PM

I just installed the rear seat. I only have two rear brackets and I found those and the hold down (front) all used 7/16 (14). The two middle seat belt holes are 1/2 (13) like the front seat belt mounts.

71jimmy · 04-27-2005, 01:36 AM

I have 4 rear brackets, all are 1/2 (13). It seems all Blazers are different in some way or other, did GM ever hear of procedures and planning? I guess it makes it interesting.

bouncytruck · 04-27-2005, 11:32 AM

Some Blazers had 4 brackets on the back of the seat and some had two. If it had two, the center two holes were for seat belt bolts.

It seems like GM did a lot of "winging-it" in the late 60's and early 70's. Consistancy wasn't their forte.

04-24-2005, 10:02 PM	#1
teamharvey Registered User Join Date: Jul 2004 Location: Turlock, Ca Posts: 578	Rear seat question Anyone know what size/length bolts are needed to install rear seat ? Are front hold down bolts the same size as the rear bracket bolts ? Thanks, Bret __________________ 71 Custom 20 Deluxe..soon to be SWB 1/2 ton 1 incredible wife 2 great kids

04-25-2005, 01:22 AM	#2
BobbyK Registered User Join Date: May 2000 Location: Petrolia,Ontario,Canada but working in Port Huron,Mi. Posts: 1,772	I think they are 7/16th x 1" or 1.25" __________________ 71 blazer,350SBC,approx.375HP,700R4,factory GM TPI.Dual electric fans,33x12.5x15 ATR on stock suspension. Petrolia,Ontario,Canada but working in Port Huron,MI. See ALL my Blazer pic's HERE

04-25-2005, 01:11 PM	#3
71jimmy Registered User Join Date: Mar 2004 Location: Sacramento, CA Posts: 1,083	I just sized mine in prep for the rear seat install. Don't know if this is "factory" correct or not because I don't have the original bolts. Used a tap to clean the threads and this is what I found: rear of seat bolts = 1/2 (13) and front rear seat bolts 7/16 (14). After guesstimating for washers and thickness of seat brackets/clamps this is what I bought at a hardware store, all grade 8: four 1/2x1-1/2x13 with a flat washer and lock washer for the rear, and two 7/16x 1 -1/4x14 with flat and lock washer for front of rear seat. __________________ '71 Jimmy, 350, SM465, NP205, 2in Tuff Country lift, 33s on rallies, TBI, softtop and hardtop "If life was fair you'd be able to afford one of each and a garage large enough to house them all." Last edited by 71jimmy; 04-25-2005 at 01:12 PM.

04-25-2005, 06:58 PM	#4
teamharvey Registered User Join Date: Jul 2004 Location: Turlock, Ca Posts: 578	Thanks ! __________________ 71 Custom 20 Deluxe..soon to be SWB 1/2 ton 1 incredible wife 2 great kids

04-25-2005, 07:08 PM	#5
bouncytruck SKINNY TIRES RULE! Join Date: Sep 2001 Location: Bothell, WA Posts: 11,038	As long as we are on the subject, the mounting "holes" for the front brackets in my '69 Blazer are different than they are in my '72. The front location doesn't have a hole that goes completely throught the bed. There are some sort of "threads" on the reinforcing piece welded to the floor, similar to a speed nut. I have yet to figure out what size bolt to use there. Anyone else have the same thing? The rear seat is listed on the glove box. __________________ bouncytruck 1972 K5 The Hauler 1994 K1500 Suburban The Daily2010 Kia Soul Wife's Ride2014 Fiat 500L

04-26-2005, 11:27 PM	#6
teamharvey Registered User Join Date: Jul 2004 Location: Turlock, Ca Posts: 578	I just installed the rear seat. I only have two rear brackets and I found those and the hold down (front) all used 7/16 (14). The two middle seat belt holes are 1/2 (13) like the front seat belt mounts. __________________ 71 Custom 20 Deluxe..soon to be SWB 1/2 ton 1 incredible wife 2 great kids

04-27-2005, 01:36 AM	#7
71jimmy Registered User Join Date: Mar 2004 Location: Sacramento, CA Posts: 1,083	I have 4 rear brackets, all are 1/2 (13). It seems all Blazers are different in some way or other, did GM ever hear of procedures and planning? I guess it makes it interesting. __________________ '71 Jimmy, 350, SM465, NP205, 2in Tuff Country lift, 33s on rallies, TBI, softtop and hardtop "If life was fair you'd be able to afford one of each and a garage large enough to house them all."

04-27-2005, 11:32 AM	#8
bouncytruck SKINNY TIRES RULE! Join Date: Sep 2001 Location: Bothell, WA Posts: 11,038	Some Blazers had 4 brackets on the back of the seat and some had two. If it had two, the center two holes were for seat belt bolts. It seems like GM did a lot of "winging-it" in the late 60's and early 70's. Consistancy wasn't their forte. __________________ bouncytruck 1972 K5 The Hauler 1994 K1500 Suburban The Daily2010 Kia Soul Wife's Ride2014 Fiat 500L

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