I torqued them to 59#'s as that is the GM spec and the RC direction said torque to factory spec. The dealership followed the TSB, which states to just torque them to 79ft/lbs. xb``c``90a: X8l8`qTC. If a torque wrench is verified to be within 4%, then it is fit for service. 0000001156 00000 n
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You may be at 85%, you may be at 93%, it's hard to say without measuring the actual strain. I assume they're the same size nuts. 0000001905 00000 n
It's the act of torquing that stretches the bolt not taking it loose. I tightened them to spec, which I believe was 85 and PROBLEM SOLVED! Probably took 2 complete revolutions. Maybe it's just my imagination, but it seems smoother to me. There's no issue with upgrading u-bolts. What happens if you over torque the U Bolt? Im going to get the front side windows tinted. Now to wait for those new tires to wear out so you can get bigger ones! 187 0 obj
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^uX; ^V3'>ryq\\$tD6V-TEBUX G.ZGuB&(qqZ4N'foqH6XX$cqwB`c 2002 Chevy 2500HD CC D/A 4x4 with 3500 springs. 0000111226 00000 n All I know is that is rather have a tight rear-end than a loose one!! 0000108955 00000 n I have a pair of old Craftsman torque wrenches for $100-$150 each. 0000007057 00000 n Looks great!! That being said, a good way to get in trouble would be to lube the bolt up, then use a torque spec for a plain, dry bolt. range, well, as stated above, GM came out with a TSB that stated 79 ft. lbs My point, with my limited knowledge, is that these bolts are made to be stretched, and can withstand far more than assumed. For a better experience, please enable JavaScript in your browser before proceeding. A forum community dedicated to Chevrolet and GMC diesel truck owners and enthusiasts.
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What's with all the super expensive torque wrenches? By using this site, you agree to our Terms of Use. If you take the same dry, unplated bolt and torque up to 100 lb-ft, you are just below 90% of proof load. THEREED, 0000036567 00000 n From buying research to owner support, join 1.5 MILLION GM Truck Enthusiasts every month who use GM-Trucks.com as a daily part of their ownership experience. 145 0 obj <> endobj A forum community dedicated to Chevrolet Silverado and GMC Sierra pickup owners and enthusiasts. 0000015585 00000 n In my situation I retorqued mine to 70#'s and felt uncomfortable knowing that it was a guess on my part. Definitely appreciate that. 0000011197 00000 n By You said you were uncomfortable in the 70 ft. lb. I'm comfortable with the ones I have though. Paste as plain text instead, Your link has been automatically embedded. 0000136931 00000 n startxref
Upload or insert images from URL. And I was uneasy wondering why they came loose from the factory! So while I was under there with the torque wrench I found the lower shock bolts were too loose. I would take them to 79 ft-lb, and while you're there, take note of the bolt size. The GM UBolt is 1/2" but measures close to 5/8" at the threads since they have cold rolled threads. I suppose time will tell. For what it's worth, part of my job here has been to evaluate situations where a torque wrench was found out of calibration and to determine if the applications where it was used need to be re-torqued. I installed Zone spacers this weekend to level the front and replaced the factory block with a 2" GM block. Clear editor. So this has me wondering if I should retorque? They were definitely loose. Everyone has their own solution to having peace of mind. Here at my job, when I need something tightened to a very precise amount, we don't bother with a high-dollar torque wrench we hydraulically stretch the bolt to achieve the exact tension / stress we require, then spin up the nut until it contacts the surface. 0000006020 00000 n 0000021356 00000 n Come join the discussion about performance, modifications, classifieds, troubleshooting, maintenance, and more! 0000009260 00000 n The Fora platform includes forum software by XenForo, VerticalScope Inc., 111 Peter Street, Suite 600, Toronto, Ontario, M5V 2H1, Canada. Still did not solve my problem. In between I had made two dealer visits and they were no help, "no problem found". 0000005630 00000 n I put the 3500 springs on and haven't noticed a big difference in the ride. After learning some tricks it went pretty smooth. Powered by Invision Community. Nice! There's a TSB bulletin somewhere on this very problem that I can't find at the moment that the bolts were undertorqued at the factory. 0000001483 00000 n 0000005820 00000 n The Fora platform includes forum software by XenForo, Duramax First Generation: 2001-2004 (LB7), Duramax Second Generation: 2004.5-2005 (LLY), Fuel System, Air, Exhaust & Emissions Upgrades, VerticalScope Inc., 111 Peter Street, Suite 600, Toronto, Ontario, M5V 2H1, Canada. Metallurgy can vary so some bolts are better than others. Nice truck! %PDF-1.5 % I'm assuming that the loose one was actually the bolt stretching, doubt the nut came loose. 0000008948 00000 n
These qualities can be simplified into a single value (called "nut factor"), but it's still an approximation. Very rarely do I need to have them re-done, and so far in the life of this plant we've had no fastener failures or leaks at these connections. This removes the approximation issue completely. I, I have a 2014 CC AT and based on forum feedback decided to check my rear leaf spring u bolts. 0000008822 00000 n Is it about as slick as a plated bolt, or more rough like dry bare metal? Come join the discussion about duramax engines, performance, builds, modifications, classifieds, troubleshooting, maintenance, and more! 0000021426 00000 n Your previous content has been restored. 0000105016 00000 n This resolved my issues for a few months but things began to change back so I attempted to remove the nuts to lube and retorque them since one was loose again. Since you ask, I borrowed a torque wrench from Cal-Tech Calibrations, right next to our fabrication shop, Gulf Coast Fab. <<1E9E5FAB16F87042B06DC2FBEBC853EB>]>> I tightened my U bolts last night to 79 lbs. they are slick, but I recall them being possibly fatter and more heavy duty feeling than the stockers when I made the swap. Throughout this forum, I'm not the only one that torqued the bolts to over 100 ft. lbs. 0000015115 00000 n Doing this is fine, since you are cutting on new thread on the bolt by torquing down more. Thanks for the help guys. That's why torque for a plated bolt is lower than an unplated, the plated has less friction. "New" Chevy owner/college student looking to upgrade one mod at a time. You cannot paste images directly. But when I put on the torque wrench they were not up to spec. Pasted as rich text. In 20 seconds you can become part of the worlds largest and oldest community discussing General Motors, Chevrolet and GMC branded pickups, crossovers, and SUVs. It's customary to add a lubricant to the threads like never seize so that you create less friction.
A 1/2" SAE grade 5 bolt is quite comfortable being used and re-used at 70-85 lb-ft (dry, depending on if it's plated or not). Especially on a half-ton truck 0 This post REALLY made the time slow down, haha. The bolts on mine were way undertorqued to only 35-40ft/lbs, caus, If you've never taken the u-bolts completely off, but simply tightened them more, there's no need to buy new ones IMO. If you were to loosen them and torque, or re-torque to a nut position less than the original position, then I fully agree you should replace the bolts and nuts. If I torque a fastener to 90% or more, I'm going to replace it. Drove it arou. I tightened them to 59# and was amazed at how much I had to tighten a couple of them. 0000014661 00000 n 0000005436 00000 n 0000137121 00000 n I have the 6.2L with larger axle. So I torqued the u bolts to 70 ft-ib as I was still a little concerned to go to 79, although the u bolts are larger and appear to be more heavy duty than stock. I got a new 5th wheel and wanted the extra spring. I get the same kit in on Friday for my 06 1500! Like I alluded to earlier, torque requirements are an approximation for achieving a particular tension and stress in a stud / bolt.
It will likely fail in some way and it may not be apparent and may not happen tomorrow. 0000004263 00000 n If it's a rough finish, you could go even further if you need. Their advice is to always replace since there is no way to know about the bolts integrity once it's been torqued to max. The bolts on mine were way undertorqued to only 35-40ft/lbs, causing clicking and popping on stop and starts. Looks good Ken. Broken u-bolts, ripped threads, stripped nuts Not a word. Larger one is accurate to 4%. 0000012306 00000 n TSB doesn't say anything about replacing them. Thanks to the OP, for posting this topic. Can anyone tell me what the rear axle spring u-bolts are to be torqued to? Friction creates resistance and can distort actual final torque. In the lift kit I just installed, they said 130 ft-lb. I haven't a doubt in my mind that I'll have a failure, although I've been proven wrong before. very small rake, somewhere between 1/2" to 1". Its got a sweet stance now. This is standard advice from any suspension guru. 0000083514 00000 n I still have a little noise on the driver side. The torque for the rear axle u-bolt nuts for the 25/35 series is 110 lb ft.
I have the Rough Country Ubolts that came with the 2.5 leveling kit. Display as a link instead, 0000007975 00000 n If you have an account, sign in now to post with your account. It's your truck and you can do what you want but take some time to research torque and U bolts. $900? 0000013478 00000 n There's a TSB bulletin somewhere on this very problem that I can't find at the moment that the bolts were undertorqued at the factory. To calculate a torque that gives you the proper preload / tension on a bolt, you have to assume a value for the friction between threads (including the pitch of the thread) and even the bolt head / nut against the mating surface. My dealer has a Snap On Digital wrench-they are very accurate, measure torque and angle and cost about $975. There is some bad advice posted in some of these responses. This appears to have taken care of my slight spring clanking that I've been experiencing. Pulling Rage'n RVT-27P or 1991 Sundowner Rancher Sport! 0000104245 00000 n 0000089183 00000 n Agreed, everyone has a solution, and at least people are leaning towards conservatism. LOL. It's what I'd be doing if I ever had to take the rear end apart! (Outside of a lab) I had mine replaced for less than $40 so why gamble??? 0000136057 00000 n They told me that a bolt stretched beyond spec will eventually break. You could be adding 30% more bolt stress than you think you are. I went to a suspension shop and had them replace with a larger diameter UBolt and have a few thousand miles with no issues. 0000108983 00000 n I'll give it a shot this weekend. 145 43 If they are stock diameter, you should have no trouble going up to 79 ft-lb per GM TSB. The bolt torque spec is based on a 1/2" bolt and 100 lbs is way over max. Well I got the lift installed yesterday and got it aligned today. HdT +RuK-dzi'SL 0000111254 00000 n trailer The threads on one had galled and I could not remove without using my impact wrench. K0\6te`F\G&5e5q]9(0Q+ *tBPupPcQE@FQ{!P:cA2.#3QNPa@'ki'Lb0 0000104966 00000 n And how accurate is your torque wrench? 0000010205 00000 n Not to loose to be visually noticeable or noticeable if I was looking under and had someone bounce on the bumper, or noticeable if I grabbed the shock. 0000089113 00000 n You can post now and register later. 0000000016 00000 n JavaScript is disabled. Does your truck still have any rake? Does anyone know the thread size so I can get the right socket to tighten, thanks! 0000083320 00000 n For a better experience, please enable JavaScript in your browser before proceeding. I've not found anyone yet with any complaints or new issues afterwards either. I don't know about thread size, but if you're asking about the nut size mine were 21mm. Yv _w\BVUCdLCpnJ(N&LbK0 )/ ZZ6*+yD lRt|u6X`@ Ex=E7=#4. Metallurgy is what we do, calibration to spec is what they do. The dealership followed the TSB, which states to just torque them to 79ft/lbs. Now that I have installed one I bet I can do a full install in about 2 1/2 hours. Looks good, ken. I know this is an older thread, but has anyone else tightened their u bolts and gotten positive results? Fullsize Truck & SUV - 2014-2019 K2XX Platform, 2015 Chevrolet Silverado 2500HD LTZ Duramax, 2015 GMC Sierra SLE Double cab 4x4 5.3L Onyx Black, Silikhan Publishing Group & GM-Trucks.com, 1999-2013 Silverado & Sierra (GMT-800/900), Breaking News - UAW and GM Reach Tentative Agreement, Costco Kicks Off Season of Values With Great GM Vehicle Deals, "Silverado Race Truck" Previews Future Silverado ZRX, New Face For 2021 Chevy Colorado Debuts On Hall Racing ZR2, Following a Hopeful Stretch UAW Now Says Strike Deal Moving Backwards.
In my mind, I'm not gambling. I'd upgrade if I were replacing, but I wouldn't replace just to torque-up. If you notice any issues driving, check again to see if they have slipped any, and you could re-torque based on the previously verified bolt size. endstream endobj 113 0 obj <>stream What is the finish on the RC u-bolts? July 21, 2016 in 2014 - 2019 Silverado & Sierra. At my first service appt, I had them torque the u-bolts and now the tiny shudder that I once had on upshifts seems to be gone. Silikhan Publishing Group & GM-Trucks.com 0000003086 00000 n Not a member of the "club", not a self appointed "this or that", not a legend in my own mind. %%EOF This I would go ahead and replace if you had to loosen, but only because torque values are imprecise. My u-bolts were under torqued from factory. 0000015757 00000 n The GM spec is intended to maximize clamping force and if done correctly stretches the bolt so that it should not be used again.
^uX; ^V3'>ryq\\$tD6V-TEBUX G.ZGuB&(qqZ4N'foqH6XX$cqwB`c 2002 Chevy 2500HD CC D/A 4x4 with 3500 springs. 0000111226 00000 n All I know is that is rather have a tight rear-end than a loose one!! 0000108955 00000 n I have a pair of old Craftsman torque wrenches for $100-$150 each. 0000007057 00000 n Looks great!! That being said, a good way to get in trouble would be to lube the bolt up, then use a torque spec for a plain, dry bolt. range, well, as stated above, GM came out with a TSB that stated 79 ft. lbs My point, with my limited knowledge, is that these bolts are made to be stretched, and can withstand far more than assumed. For a better experience, please enable JavaScript in your browser before proceeding. A forum community dedicated to Chevrolet and GMC diesel truck owners and enthusiasts.
xref 0000011509 00000 n
What's with all the super expensive torque wrenches? By using this site, you agree to our Terms of Use. If you take the same dry, unplated bolt and torque up to 100 lb-ft, you are just below 90% of proof load. THEREED, 0000036567 00000 n From buying research to owner support, join 1.5 MILLION GM Truck Enthusiasts every month who use GM-Trucks.com as a daily part of their ownership experience. 145 0 obj <> endobj A forum community dedicated to Chevrolet Silverado and GMC Sierra pickup owners and enthusiasts. 0000015585 00000 n In my situation I retorqued mine to 70#'s and felt uncomfortable knowing that it was a guess on my part. Definitely appreciate that. 0000011197 00000 n By You said you were uncomfortable in the 70 ft. lb. I'm comfortable with the ones I have though. Paste as plain text instead, Your link has been automatically embedded. 0000136931 00000 n startxref
Upload or insert images from URL. And I was uneasy wondering why they came loose from the factory! So while I was under there with the torque wrench I found the lower shock bolts were too loose. I would take them to 79 ft-lb, and while you're there, take note of the bolt size. The GM UBolt is 1/2" but measures close to 5/8" at the threads since they have cold rolled threads. I suppose time will tell. For what it's worth, part of my job here has been to evaluate situations where a torque wrench was found out of calibration and to determine if the applications where it was used need to be re-torqued. I installed Zone spacers this weekend to level the front and replaced the factory block with a 2" GM block. Clear editor. So this has me wondering if I should retorque? They were definitely loose. Everyone has their own solution to having peace of mind. Here at my job, when I need something tightened to a very precise amount, we don't bother with a high-dollar torque wrench we hydraulically stretch the bolt to achieve the exact tension / stress we require, then spin up the nut until it contacts the surface. 0000006020 00000 n 0000021356 00000 n Come join the discussion about performance, modifications, classifieds, troubleshooting, maintenance, and more! 0000009260 00000 n The Fora platform includes forum software by XenForo, VerticalScope Inc., 111 Peter Street, Suite 600, Toronto, Ontario, M5V 2H1, Canada. Still did not solve my problem. In between I had made two dealer visits and they were no help, "no problem found". 0000005630 00000 n I put the 3500 springs on and haven't noticed a big difference in the ride. After learning some tricks it went pretty smooth. Powered by Invision Community. Nice! There's a TSB bulletin somewhere on this very problem that I can't find at the moment that the bolts were undertorqued at the factory. 0000001483 00000 n 0000005820 00000 n The Fora platform includes forum software by XenForo, Duramax First Generation: 2001-2004 (LB7), Duramax Second Generation: 2004.5-2005 (LLY), Fuel System, Air, Exhaust & Emissions Upgrades, VerticalScope Inc., 111 Peter Street, Suite 600, Toronto, Ontario, M5V 2H1, Canada. Metallurgy can vary so some bolts are better than others. Nice truck! %PDF-1.5 % I'm assuming that the loose one was actually the bolt stretching, doubt the nut came loose. 0000008948 00000 n
These qualities can be simplified into a single value (called "nut factor"), but it's still an approximation. Very rarely do I need to have them re-done, and so far in the life of this plant we've had no fastener failures or leaks at these connections. This removes the approximation issue completely. I, I have a 2014 CC AT and based on forum feedback decided to check my rear leaf spring u bolts. 0000008822 00000 n Is it about as slick as a plated bolt, or more rough like dry bare metal? Come join the discussion about duramax engines, performance, builds, modifications, classifieds, troubleshooting, maintenance, and more! 0000021426 00000 n Your previous content has been restored. 0000105016 00000 n This resolved my issues for a few months but things began to change back so I attempted to remove the nuts to lube and retorque them since one was loose again. Since you ask, I borrowed a torque wrench from Cal-Tech Calibrations, right next to our fabrication shop, Gulf Coast Fab. <<1E9E5FAB16F87042B06DC2FBEBC853EB>]>> I tightened my U bolts last night to 79 lbs. they are slick, but I recall them being possibly fatter and more heavy duty feeling than the stockers when I made the swap. Throughout this forum, I'm not the only one that torqued the bolts to over 100 ft. lbs. 0000015115 00000 n Doing this is fine, since you are cutting on new thread on the bolt by torquing down more. Thanks for the help guys. That's why torque for a plated bolt is lower than an unplated, the plated has less friction. "New" Chevy owner/college student looking to upgrade one mod at a time. You cannot paste images directly. But when I put on the torque wrench they were not up to spec. Pasted as rich text. In 20 seconds you can become part of the worlds largest and oldest community discussing General Motors, Chevrolet and GMC branded pickups, crossovers, and SUVs. It's customary to add a lubricant to the threads like never seize so that you create less friction.
A 1/2" SAE grade 5 bolt is quite comfortable being used and re-used at 70-85 lb-ft (dry, depending on if it's plated or not). Especially on a half-ton truck 0 This post REALLY made the time slow down, haha. The bolts on mine were way undertorqued to only 35-40ft/lbs, caus, If you've never taken the u-bolts completely off, but simply tightened them more, there's no need to buy new ones IMO. If you were to loosen them and torque, or re-torque to a nut position less than the original position, then I fully agree you should replace the bolts and nuts. If I torque a fastener to 90% or more, I'm going to replace it. Drove it arou. I tightened them to 59# and was amazed at how much I had to tighten a couple of them. 0000014661 00000 n 0000005436 00000 n 0000137121 00000 n I have the 6.2L with larger axle. So I torqued the u bolts to 70 ft-ib as I was still a little concerned to go to 79, although the u bolts are larger and appear to be more heavy duty than stock. I got a new 5th wheel and wanted the extra spring. I get the same kit in on Friday for my 06 1500! Like I alluded to earlier, torque requirements are an approximation for achieving a particular tension and stress in a stud / bolt.
It will likely fail in some way and it may not be apparent and may not happen tomorrow. 0000004263 00000 n If it's a rough finish, you could go even further if you need. Their advice is to always replace since there is no way to know about the bolts integrity once it's been torqued to max. The bolts on mine were way undertorqued to only 35-40ft/lbs, causing clicking and popping on stop and starts. Looks good Ken. Broken u-bolts, ripped threads, stripped nuts Not a word. Larger one is accurate to 4%. 0000012306 00000 n TSB doesn't say anything about replacing them. Thanks to the OP, for posting this topic. Can anyone tell me what the rear axle spring u-bolts are to be torqued to? Friction creates resistance and can distort actual final torque. In the lift kit I just installed, they said 130 ft-lb. I haven't a doubt in my mind that I'll have a failure, although I've been proven wrong before. very small rake, somewhere between 1/2" to 1". Its got a sweet stance now. This is standard advice from any suspension guru. 0000083514 00000 n I still have a little noise on the driver side. The torque for the rear axle u-bolt nuts for the 25/35 series is 110 lb ft.
I have the Rough Country Ubolts that came with the 2.5 leveling kit. Display as a link instead, 0000007975 00000 n If you have an account, sign in now to post with your account. It's your truck and you can do what you want but take some time to research torque and U bolts. $900? 0000013478 00000 n There's a TSB bulletin somewhere on this very problem that I can't find at the moment that the bolts were undertorqued at the factory. To calculate a torque that gives you the proper preload / tension on a bolt, you have to assume a value for the friction between threads (including the pitch of the thread) and even the bolt head / nut against the mating surface. My dealer has a Snap On Digital wrench-they are very accurate, measure torque and angle and cost about $975. There is some bad advice posted in some of these responses. This appears to have taken care of my slight spring clanking that I've been experiencing. Pulling Rage'n RVT-27P or 1991 Sundowner Rancher Sport! 0000104245 00000 n 0000089183 00000 n Agreed, everyone has a solution, and at least people are leaning towards conservatism. LOL. It's what I'd be doing if I ever had to take the rear end apart! (Outside of a lab) I had mine replaced for less than $40 so why gamble??? 0000136057 00000 n They told me that a bolt stretched beyond spec will eventually break. You could be adding 30% more bolt stress than you think you are. I went to a suspension shop and had them replace with a larger diameter UBolt and have a few thousand miles with no issues. 0000108983 00000 n I'll give it a shot this weekend. 145 43 If they are stock diameter, you should have no trouble going up to 79 ft-lb per GM TSB. The bolt torque spec is based on a 1/2" bolt and 100 lbs is way over max. Well I got the lift installed yesterday and got it aligned today. HdT +RuK-dzi'SL 0000111254 00000 n trailer The threads on one had galled and I could not remove without using my impact wrench. K0\6te`F\G&5e5q]9(0Q+ *tBPupPcQE@FQ{!P:cA2.#3QNPa@'ki'Lb0 0000104966 00000 n And how accurate is your torque wrench? 0000010205 00000 n Not to loose to be visually noticeable or noticeable if I was looking under and had someone bounce on the bumper, or noticeable if I grabbed the shock. 0000089113 00000 n You can post now and register later. 0000000016 00000 n JavaScript is disabled. Does your truck still have any rake? Does anyone know the thread size so I can get the right socket to tighten, thanks! 0000083320 00000 n For a better experience, please enable JavaScript in your browser before proceeding. I've not found anyone yet with any complaints or new issues afterwards either. I don't know about thread size, but if you're asking about the nut size mine were 21mm. Yv _w\BVUCdLCpnJ(N&LbK0 )/ ZZ6*+yD lRt|u6X`@ Ex=E7=#4. Metallurgy is what we do, calibration to spec is what they do. The dealership followed the TSB, which states to just torque them to 79ft/lbs. Now that I have installed one I bet I can do a full install in about 2 1/2 hours. Looks good, ken. I know this is an older thread, but has anyone else tightened their u bolts and gotten positive results? Fullsize Truck & SUV - 2014-2019 K2XX Platform, 2015 Chevrolet Silverado 2500HD LTZ Duramax, 2015 GMC Sierra SLE Double cab 4x4 5.3L Onyx Black, Silikhan Publishing Group & GM-Trucks.com, 1999-2013 Silverado & Sierra (GMT-800/900), Breaking News - UAW and GM Reach Tentative Agreement, Costco Kicks Off Season of Values With Great GM Vehicle Deals, "Silverado Race Truck" Previews Future Silverado ZRX, New Face For 2021 Chevy Colorado Debuts On Hall Racing ZR2, Following a Hopeful Stretch UAW Now Says Strike Deal Moving Backwards.
In my mind, I'm not gambling. I'd upgrade if I were replacing, but I wouldn't replace just to torque-up. If you notice any issues driving, check again to see if they have slipped any, and you could re-torque based on the previously verified bolt size. endstream endobj 113 0 obj <>stream What is the finish on the RC u-bolts? July 21, 2016 in 2014 - 2019 Silverado & Sierra. At my first service appt, I had them torque the u-bolts and now the tiny shudder that I once had on upshifts seems to be gone. Silikhan Publishing Group & GM-Trucks.com 0000003086 00000 n Not a member of the "club", not a self appointed "this or that", not a legend in my own mind. %%EOF This I would go ahead and replace if you had to loosen, but only because torque values are imprecise. My u-bolts were under torqued from factory. 0000015757 00000 n The GM spec is intended to maximize clamping force and if done correctly stretches the bolt so that it should not be used again.