Frame Replacement Bolts - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**1971Stepside** · 05-01-2002, 05:43 PM

I have a couple of crossmembers that I am replacing tonight and will need nuts and bolts to replace the old rivet. What size diameter are those rivet holes and what strength bolt is recommended?

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2001 GMC 2500HD Crew Cab Duramax, Allison, 4WD, Love it

1971 Chevrolet 1/2 ton 2WD Short/Step Side. In process of frame off restoration

69 longhorn · 05-01-2002, 05:47 PM

the rivet holes are probably 3/8. I have replaced anything that was out of the longhorn with 7/16 grade 8 hardware& pinch lock nuts.......69

**1971Stepside** · 05-01-2002, 05:50 PM

Sorry 69 to be dense. Should I go with the 3/8 or the 7/16? I live a ways from the hardware store and don't want to make a second trip if possible. Any help would be greatly appreciated.

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2001 GMC 2500HD Crew Cab Duramax, Allison, 4WD, Love it

1971 Chevrolet 1/2 ton 2WD Short/Step Side. In process of frame off restoration

69 longhorn · 05-01-2002, 06:06 PM

My goof,I should have stated that I drilled the hole oversized to fit the 7/16 bolts. Im guessin trans crossmember,& farther back...69

OLDCHEV4X4 · 05-01-2002, 06:38 PM

I replaced over 60 rivets on my 4x4 frame. I ground a flat spot on the rivet head. Then center punched them. Drilled them with a 1/8 drill about a 1/4 or so deep. Then drilled them with a 3/8 drill the same depth. I didnt want to oval out the hole. Then i took a chizle ond knocked the head off and punched the rivet out..After that i drilled all the holes out at 7/16 because a 7/16-20 bolt measures .429 to .431 and i wanted them to fit tight like a rivet. Then i sand blasted everything and painted it. When i assembled everything i put a flat washer on both sides and put red locktight in the bolt and torqued em down. I can't remember the torque speck.. The bolts were 7/16-20x1" long grade 8.....
Randy

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72 k/10 short wideside
72 k/5 Blazer
72 custom/10 8' bed
69 c/10 8' bed
71 k/5......rusty!! IT WENT TO THE SCRAP YARD
72 custom/10 short stepside
70 C-30 Longhorn, its Longhornmail's now.
70 K-5 Blazer
chester county pennsylvania

Duallie · 05-02-2002, 01:31 AM

For critical frame bolts (like suspension and crossmembers) I like to use lugstuds PRESSED into a reamed-to-fit hole and cinched down with a lubricated nylock nut. Looks just like a rivet on the outside, and splined and pressed in for immobility. I have been known to use old studs from whatever old suspension I have layin' around, but new is good, too. Use a generic GM stud from a malibu, for instance.

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Just as if I knew what I was doin'

**1971Stepside** · 05-02-2002, 08:57 AM

Thanks for all your help. I got some 3/8 grade 8 3/4" Bolts and they fit the holes perfect and were just the right length. Replacing the first crossmember (in front of the engine) was a job! But, I won in the end.

My truck was a manual to begin with years ago and after I got the cab off the frame I found the new auto trans crossmember only had two bolts holding it in the frame!!! That has been corrected!!

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2001 GMC 2500HD Crew Cab Duramax, Allison, 4WD, Love it

1971 Chevrolet 1/2 ton 2WD Short/Step Side. In process of frame off restoration

sevenwonder · 05-03-2002, 11:25 PM

Lug bolts sounds like a good ideal. I'm going to cheak that out myself. If using bolts be sure to use grade 8.

MOTHERTRUCKERS · 05-06-2002, 08:24 AM

grade 8 has a better clamping strength but a lower shear strength, grade 5 is the recommended bolt to use for frames that flex.

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www.mothertruckers.net

05-01-2002, 05:43 PM	#1
1971Stepside Almost Satisfied Join Date: Mar 2002 Location: Springfield, MO Posts: 2,932	Frame Replacement Bolts I have a couple of crossmembers that I am replacing tonight and will need nuts and bolts to replace the old rivet. What size diameter are those rivet holes and what strength bolt is recommended? ------------------ 2001 GMC 2500HD Crew Cab Duramax, Allison, 4WD, Love it 1971 Chevrolet 1/2 ton 2WD Short/Step Side. In process of frame off restoration __________________ 1971 C10 Stepside. LSx 6.0 with BTR Stage IV, Speed Engineering Headers, 4L80e transmission w/3200 Circle-D Stall. 3.73. Posi. Purchased this truck when I was 17. I started the rebuild (or take apart) in 1993. I have drug it around all over the country in pieces. Finally back on the road in 2021. "I can't complain, but sometimes I still do. Life's been good to me so far."

05-01-2002, 05:47 PM	#2
69 longhorn Registered User Join Date: Aug 2001 Location: rock island,il,usa Posts: 5,382	the rivet holes are probably 3/8. I have replaced anything that was out of the longhorn with 7/16 grade 8 hardware& pinch lock nuts.......69 __________________ http://community.webshots.com/user/hotrodhorn

05-01-2002, 05:50 PM	#3
1971Stepside Almost Satisfied Join Date: Mar 2002 Location: Springfield, MO Posts: 2,932	Sorry 69 to be dense. Should I go with the 3/8 or the 7/16? I live a ways from the hardware store and don't want to make a second trip if possible. Any help would be greatly appreciated. ------------------ 2001 GMC 2500HD Crew Cab Duramax, Allison, 4WD, Love it 1971 Chevrolet 1/2 ton 2WD Short/Step Side. In process of frame off restoration __________________ 1971 C10 Stepside. LSx 6.0 with BTR Stage IV, Speed Engineering Headers, 4L80e transmission w/3200 Circle-D Stall. 3.73. Posi. Purchased this truck when I was 17. I started the rebuild (or take apart) in 1993. I have drug it around all over the country in pieces. Finally back on the road in 2021. "I can't complain, but sometimes I still do. Life's been good to me so far."

05-01-2002, 06:06 PM	#4
69 longhorn Registered User Join Date: Aug 2001 Location: rock island,il,usa Posts: 5,382	My goof,I should have stated that I drilled the hole oversized to fit the 7/16 bolts. Im guessin trans crossmember,& farther back...69 __________________ http://community.webshots.com/user/hotrodhorn

05-01-2002, 06:38 PM	#5
OLDCHEV4X4 Registered User Join Date: Apr 2000 Location: Chester County PA, USA Posts: 1,228	I replaced over 60 rivets on my 4x4 frame. I ground a flat spot on the rivet head. Then center punched them. Drilled them with a 1/8 drill about a 1/4 or so deep. Then drilled them with a 3/8 drill the same depth. I didnt want to oval out the hole. Then i took a chizle ond knocked the head off and punched the rivet out..After that i drilled all the holes out at 7/16 because a 7/16-20 bolt measures .429 to .431 and i wanted them to fit tight like a rivet. Then i sand blasted everything and painted it. When i assembled everything i put a flat washer on both sides and put red locktight in the bolt and torqued em down. I can't remember the torque speck.. The bolts were 7/16-20x1" long grade 8..... Randy ------------------ 72 k/10 short wideside 72 k/5 Blazer 72 custom/10 8' bed 69 c/10 8' bed 71 k/5......rusty!! IT WENT TO THE SCRAP YARD 72 custom/10 short stepside 70 C-30 Longhorn, its Longhornmail's now. 70 K-5 Blazer chester county pennsylvania __________________ 72 k/10 short wideside 72 k/5 Blazer 72 K/5 Blazer - obstacle course racer 72 custom/10 8' bed 70 K/5 Blazer 67 C-30 GMC Flat bed 86 GMC K2500 Plow Truck 85 GMC K3500 84 M1008 85 M1008 77 G30 Motor Home 72 Sears 12hp Tractor Glenmoore, Pennsylvania

05-02-2002, 01:31 AM	#6
Duallie Registered User Join Date: Feb 2001 Location: Nikiski, Alaska Posts: 477	For critical frame bolts (like suspension and crossmembers) I like to use lugstuds PRESSED into a reamed-to-fit hole and cinched down with a lubricated nylock nut. Looks just like a rivet on the outside, and splined and pressed in for immobility. I have been known to use old studs from whatever old suspension I have layin' around, but new is good, too. Use a generic GM stud from a malibu, for instance. ------------------ Just as if I knew what I was doin' __________________ Just as if I knew what I was doin'

05-02-2002, 08:57 AM	#7
1971Stepside Almost Satisfied Join Date: Mar 2002 Location: Springfield, MO Posts: 2,932	Thanks for all your help. I got some 3/8 grade 8 3/4" Bolts and they fit the holes perfect and were just the right length. Replacing the first crossmember (in front of the engine) was a job! But, I won in the end. My truck was a manual to begin with years ago and after I got the cab off the frame I found the new auto trans crossmember only had two bolts holding it in the frame!!! That has been corrected!! ------------------ 2001 GMC 2500HD Crew Cab Duramax, Allison, 4WD, Love it 1971 Chevrolet 1/2 ton 2WD Short/Step Side. In process of frame off restoration __________________ 1971 C10 Stepside. LSx 6.0 with BTR Stage IV, Speed Engineering Headers, 4L80e transmission w/3200 Circle-D Stall. 3.73. Posi. Purchased this truck when I was 17. I started the rebuild (or take apart) in 1993. I have drug it around all over the country in pieces. Finally back on the road in 2021. "I can't complain, but sometimes I still do. Life's been good to me so far."

05-03-2002, 11:25 PM	#8
sevenwonder Registered User Join Date: Mar 2002 Location: Shady Spring,WV Posts: 37	Lug bolts sounds like a good ideal. I'm going to cheak that out myself. If using bolts be sure to use grade 8. __________________ 70 short,step on a 72 frame.

05-06-2002, 08:24 AM	#9
MOTHERTRUCKERS Registered User Join Date: Dec 1999 Location: BRADENTON FLA Posts: 3,269	grade 8 has a better clamping strength but a lower shear strength, grade 5 is the recommended bolt to use for frames that flex. ------------------ www.mothertruckers.net __________________ Rest in Peace Ed. Thanks for all the good times.



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