U-bolt size on lower control arm shafts ? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

GMCGRANDS · 08-02-2004, 08:25 PM

I ordered some replacement u-bolts for the lower control arm shafts on my 72 GMC. When I recieved them they were 7/16" dia. The orginal ones are 1/2" ? Anyone else run into this? I checked the shafts they are the same. The spread of the ubolts is the same, just the diameter is different and the holes in the crossmember are different when compared to another crossmember I have. I think I remember Phantom Dually having a problem like this one time.

**lolife99** · 08-02-2004, 10:15 PM

I am in the same situation right now. Stock is 1/2 inch. I was told buy a gm parts man, (30 plus years at the same dealership) that they changed to 9/16" in '73, due to the 1/2" ones breaking. He remembers the bulletin on it from back then. I ordered the 9/16" cause that was all that is still available. $3.87 each my cost. I can get you a part number if you need it. He said to open up the holes in the frame brackets. I am going this route because, even sand blasted,... mine look pretty unsafe, from all the rust. Anyone else?

SCOTI · 08-02-2004, 11:32 PM

I believe the size change co-incided w/the change to discs as standard equipment.

MrShelley · 08-03-2004, 12:22 AM

I'd like that part number. My local dealership is full of morons who would rather try to sell me a new truck than take the time to look up the part I need.

64fleetside · 08-03-2004, 01:08 AM

Just replaced them on mine, spent $10 on a drill bit, used a 1/2 inch electric drill & HANG ON! There is about three thicknesses of metal there, a little tough to drill lyiing on your back. Brian

**lolife99** · 08-03-2004, 08:22 AM

I will get it tonight,... after work.

MrShelley · 08-03-2004, 11:57 AM

Thanks lolife

**lolife99** · 08-03-2004, 10:40 PM

MrShelley,... heres your Gm part #(345970). List price was $5.16, and dealer net price is $3.87. This is the u-bolts only! You have to provide your own lock nuts and washers. Sorry it took so long,... I had to work over tonight. Lolife.

phantom dually · 08-04-2004, 06:40 PM

LMC also has these listed in there catalog I beleive.

GMCGRANDS · 08-04-2004, 10:06 PM

So is there three sizes (7/16, 1/2, 9/16)? I have two crossmembers ones 7/16 and the orginal 72' one with disc brakes is 1/2".

**lolife99** · 08-05-2004, 07:54 AM

7/16 for drum brakes, 1/2 for 71-72 discs, and 9/16 for 73-87?

64fleetside · 08-11-2004, 08:44 AM

I have a 64,66,69,70,71, & 72 1/2 tons in my yard right now in various stages of repair/disrepair/parting. All have the same spindly u-bolts. I have seen the larger ones installed on 3/4 & 1 ton trucks. Brian

08-02-2004, 08:25 PM	#1
GMCGRANDS Registered User Join Date: Jan 2001 Location: Franklin , N.C. USA Posts: 105	U-bolt size on lower control arm shafts ? I ordered some replacement u-bolts for the lower control arm shafts on my 72 GMC. When I recieved them they were 7/16" dia. The orginal ones are 1/2" ? Anyone else run into this? I checked the shafts they are the same. The spread of the ubolts is the same, just the diameter is different and the holes in the crossmember are different when compared to another crossmember I have. I think I remember Phantom Dually having a problem like this one time. __________________ Mark 72'GMC Sierra Grande 2wd SWB, Fatman stageV IFS, 6.0 liter LQ4 Gen 3 and 4L80E under construction 05' GMC Sierra Denali LQ9

08-02-2004, 11:32 PM	#3
SCOTI Registered User Join Date: Apr 2001 Location: DALLAS,TX Posts: 22,066	I believe the size change co-incided w/the change to discs as standard equipment. __________________ 67SWB-B.B.RetroRod 64SWB-Recycle 89CCDually-Driver/Tow Truck 99CCSWB Driver All Fleetsides @rattlecankustoms in IG Building a small, high rpm engine with the perfect bore, stroke and rod ratio is very impressive. It's like a highly skilled Morrocan sword fighter with a Damascus Steel Scimitar..... *Cubic inches is like Indiana Jones with a cheap pistol.*

08-03-2004, 12:22 AM	#4
MrShelley Too Many Clubs Club Join Date: Jul 2003 Location: Kilgore, Texas Posts: 443	I'd like that part number. My local dealership is full of morons who would rather try to sell me a new truck than take the time to look up the part I need. __________________ How I installed my air bags...

08-03-2004, 11:57 AM	#7
MrShelley Too Many Clubs Club Join Date: Jul 2003 Location: Kilgore, Texas Posts: 443	Thanks lolife __________________ How I installed my air bags...

08-03-2004, 10:40 PM	#8
lolife99 67-72 parts collector,… Join Date: Nov 2002 Location: Mid-MO Posts: 22,700	GM part number,... MrShelley,... heres your Gm part #(345970). List price was $5.16, and dealer net price is $3.87. This is the u-bolts only! You have to provide your own lock nuts and washers. Sorry it took so long,... I had to work over tonight. Lolife.

08-02-2004, 10:15 PM	#2
lolife99 67-72 parts collector,… Join Date: Nov 2002 Location: Mid-MO Posts: 22,700	I am in the same situation right now. Stock is 1/2 inch. I was told buy a gm parts man, (30 plus years at the same dealership) that they changed to 9/16" in '73, due to the 1/2" ones breaking. He remembers the bulletin on it from back then. I ordered the 9/16" cause that was all that is still available. $3.87 each my cost. I can get you a part number if you need it. He said to open up the holes in the frame brackets. I am going this route because, even sand blasted,... mine look pretty unsafe, from all the rust. Anyone else?

08-03-2004, 01:08 AM	#5
64fleetside Registered User Join Date: Apr 2004 Location: arkieland Posts: 1,070	Just replaced them on mine, spent $10 on a drill bit, used a 1/2 inch electric drill & HANG ON! There is about three thicknesses of metal there, a little tough to drill lyiing on your back. Brian

08-03-2004, 08:22 AM	#6
lolife99 67-72 parts collector,… Join Date: Nov 2002 Location: Mid-MO Posts: 22,700	I will get it tonight,... after work.

08-04-2004, 06:40 PM	#9
phantom dually Project92 SWB stepside Join Date: Feb 2003 Location: Louisville KY Posts: 4,792	LMC also has these listed in there catalog I beleive. __________________ 92 C1500 stepside 496 Stroker Competiton Engineering Ladder bars/QA1 coilovers. Dana 60 rear with 4.10 gear and posi. Bonspeed Palisade 20x12 in rear w/335/30/20 and 20x8.5 front w/245/40/20. 5/8 drop with Belltech springs/DJM spindles/drop shocks. WWS Progress thread http://67-72chevytrucks.com/vboard/s...d.php?t=140448

08-04-2004, 10:06 PM	#10
GMCGRANDS Registered User Join Date: Jan 2001 Location: Franklin , N.C. USA Posts: 105	So is there three sizes (7/16, 1/2, 9/16)? I have two crossmembers ones 7/16 and the orginal 72' one with disc brakes is 1/2". __________________ Mark 72'GMC Sierra Grande 2wd SWB, Fatman stageV IFS, 6.0 liter LQ4 Gen 3 and 4L80E under construction 05' GMC Sierra Denali LQ9

08-05-2004, 07:54 AM	#11
lolife99 67-72 parts collector,… Join Date: Nov 2002 Location: Mid-MO Posts: 22,700	7/16 for drum brakes, 1/2 for 71-72 discs, and 9/16 for 73-87?

08-11-2004, 08:44 AM	#12
64fleetside Registered User Join Date: Apr 2004 Location: arkieland Posts: 1,070	I have a 64,66,69,70,71, & 72 1/2 tons in my yard right now in various stages of repair/disrepair/parting. All have the same spindly u-bolts. I have seen the larger ones installed on 3/4 & 1 ton trucks. Brian

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