I tightened them to 59# and was amazed at how much I had to tighten a couple of them. Yv _w\BVUCdLCpnJ(N&LbK0 )/ ZZ6*+yD lRt|u6X`@ Ex=E7=#4. trailer I'm assuming that the loose one was actually the bolt stretching, doubt the nut came loose. JavaScript is disabled. Paste as plain text instead, And how accurate is your torque wrench? I'll give it a shot this weekend. 0000009260 00000 n The GM UBolt is 1/2" but measures close to 5/8" at the threads since they have cold rolled threads. 0000005820 00000 n I'd upgrade if I were replacing, but I wouldn't replace just to torque-up. 0000104245 00000 n 0000021356 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. After learning some tricks it went pretty smooth. My dealer has a Snap On Digital wrench-they are very accurate, measure torque and angle and cost about $975. I installed Zone spacers this weekend to level the front and replaced the factory block with a 2" GM block. 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. There is some bad advice posted in some of these responses. Definitely appreciate that. This removes the approximation issue completely. What happens if you over torque the U Bolt? 0000105016 00000 n 0000013478 00000 n I assume they're the same size nuts. HdT +RuK-dzi'SL 0000006020 00000 n (Outside of a lab) I had mine replaced for less than $40 so why gamble??? %%EOF These qualities can be simplified into a single value (called "nut factor"), but it's still an approximation. But when I put on the torque wrench they were not up to spec. That's why torque for a plated bolt is lower than an unplated, the plated has less friction. What is the finish on the RC u-bolts? 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. 0000004263 00000 n 0000021426 00000 n I've not found anyone yet with any complaints or new issues afterwards either. Their advice is to always replace since there is no way to know about the bolts integrity once it's been torqued to max. I don't know about thread size, but if you're asking about the nut size mine were 21mm. Now to wait for those new tires to wear out so you can get bigger ones! Larger one is accurate to 4%. 0000083320 00000 n LOL. I went to a suspension shop and had them replace with a larger diameter UBolt and have a few thousand miles with no issues. 0000001549 00000 n very small rake, somewhere between 1/2" to 1". 0000007057 00000 n 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 20 seconds you can become part of the worlds largest and oldest community discussing General Motors, Chevrolet and GMC branded pickups, crossovers, and SUVs. Pulling Rage'n RVT-27P or 1991 Sundowner Rancher Sport! Broken u-bolts, ripped threads, stripped nuts Not a word. If I torque a fastener to 90% or more, I'm going to replace it. 0000108983 00000 n Nice! 145 43 0000007975 00000 n 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. 0000015115 00000 n You cannot paste images directly. <<1E9E5FAB16F87042B06DC2FBEBC853EB>]>> You could be adding 30% more bolt stress than you think you are. 0000000016 00000 n Is it about as slick as a plated bolt, or more rough like dry bare metal? "New" Chevy owner/college student looking to upgrade one mod at a time. They were definitely loose. I got a new 5th wheel and wanted the extra spring. TSB doesn't say anything about replacing them. endstream endobj 113 0 obj <>stream July 21, 2016 in 2014 - 2019 Silverado & Sierra. It's what I'd be doing if I ever had to take the rear end apart! By using this site, you agree to our Terms of Use. Its got a sweet stance now. Everyone has their own solution to having peace of mind. 0000001483 00000 n 0000003086 00000 n By This I would go ahead and replace if you had to loosen, but only because torque values are imprecise. In my situation I retorqued mine to 70#'s and felt uncomfortable knowing that it was a guess on my part. 0000036567 00000 n 0000001156 00000 n So this has me wondering if I should retorque? xref Thanks to the OP, for posting this topic. 0000001905 00000 n 0000015585 00000 n The bolt torque spec is based on a 1/2" bolt and 100 lbs is way over max. 0000011197 00000 n 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. The threads on one had galled and I could not remove without using my impact wrench. Upload or insert images from URL. What's with all the super expensive torque wrenches? 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. 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 have a pair of old Craftsman torque wrenches for $100-$150 each. $900? 2002 Chevy 2500HD CC D/A 4x4 with 3500 springs. All I know is that is rather have a tight rear-end than a loose one!! 0000011066 00000 n It's customary to add a lubricant to the threads like never seize so that you create less friction. Throughout this forum, I'm not the only one that torqued the bolts to over 100 ft. lbs. Well I got the lift installed yesterday and got it aligned today. A forum community dedicated to Chevrolet and GMC diesel truck owners and enthusiasts. 0000008948 00000 n Looks good Ken. In my mind, I'm not gambling. Looks great!! 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. 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. There's no issue with upgrading u-bolts. You can post now and register later. It's the act of torquing that stretches the bolt not taking it loose. I would take them to 79 ft-lb, and while you're there, take note of the bolt size. 0000108955 00000 n 0000104966 00000 n The Fora platform includes forum software by XenForo, VerticalScope Inc., 111 Peter Street, Suite 600, Toronto, Ontario, M5V 2H1, Canada. Maybe it's just my imagination, but it seems smoother to me. If they are stock diameter, you should have no trouble going up to 79 ft-lb per GM TSB. 0000011509 00000 n Does anyone know the thread size so I can get the right socket to tighten, thanks! 0000089113 00000 n It will likely fail in some way and it may not be apparent and may not happen tomorrow. Now that I have installed one I bet I can do a full install in about 2 1/2 hours. Since you ask, I borrowed a torque wrench from Cal-Tech Calibrations, right next to our fabrication shop, Gulf Coast Fab. 0000005630 00000 n The bolts on mine were way undertorqued to only 35-40ft/lbs, causing clicking and popping on stop and starts. For a better experience, please enable JavaScript in your browser before proceeding. This is standard advice from any suspension guru. THEREED, I tightened them to spec, which I believe was 85 and PROBLEM SOLVED! In the lift kit I just installed, they said 130 ft-lb. ^uX; ^V3'>ryq\\$tD6V-TEBUX G.ZGuB&(qqZ4N'foqH6XX$cqwB`c I have the Rough Country Ubolts that came with the 2.5 leveling kit. 0000111254 00000 n Im going to get the front side windows tinted. 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. This appears to have taken care of my slight spring clanking that I've been experiencing. Powered by Invision Community. Pasted as rich text. Especially on a half-ton truck Friction creates resistance and can distort actual final torque. Display as a link instead, 0000137121 00000 n Can anyone tell me what the rear axle spring u-bolts are to be torqued to? I suppose time will tell. The dealership followed the TSB, which states to just torque them to 79ft/lbs. JavaScript is disabled. Looks good, ken. %PDF-1.5 % 0000008822 00000 n If it's a rough finish, you could go even further if you need. I have the 6.2L with larger axle. Does your truck still have any rake? 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. 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. Nice truck! If a torque wrench is verified to be within 4%, then it is fit for service. 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. xb``c``90a: X8l8`qTC. I still have a little noise on the driver side. And I was uneasy wondering why they came loose from the factory! The GM spec is intended to maximize clamping force and if done correctly stretches the bolt so that it should not be used again. In between I had made two dealer visits and they were no help, "no problem found". The torque for the rear axle u-bolt nuts for the 25/35 series is 110 lb ft. 0000089183 00000 n Come join the discussion about performance, modifications, classifieds, troubleshooting, maintenance, and more! 0000111226 00000 n This post REALLY made the time slow down, haha. they are slick, but I recall them being possibly fatter and more heavy duty feeling than the stockers when I made the swap. Doing this is fine, since you are cutting on new thread on the bolt by torquing down more. Clear editor. Drove it arou. A forum community dedicated to Chevrolet Silverado and GMC Sierra pickup owners and enthusiasts. 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. So while I was under there with the torque wrench I found the lower shock bolts were too loose. I know this is an older thread, but has anyone else tightened their u bolts and gotten positive results? 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. K0\6te`F\G&5e5q]9(0Q+ *tBPupPcQE@FQ{!P:cA2.#3QNPa@'ki'Lb0 The dealership followed the TSB, which states to just torque them to 79ft/lbs. 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. If you have an account, sign in now to post with your account. Your link has been automatically embedded. You may be at 85%, you may be at 93%, it's hard to say without measuring the actual strain. I torqued them to 59#'s as that is the GM spec and the RC direction said torque to factory spec. 0000136931 00000 n startxref Thanks for the help guys. It's your truck and you can do what you want but take some time to research torque and U bolts. Probably took 2 complete revolutions. They told me that a bolt stretched beyond spec will eventually break. Your previous content has been restored. Metallurgy can vary so some bolts are better than others. 0000010205 00000 n 0000005436 00000 n I haven't a doubt in my mind that I'll have a failure, although I've been proven wrong before. 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). For a better experience, please enable JavaScript in your browser before proceeding. 0000083514 00000 n 187 0 obj <>stream 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. If you take the same dry, unplated bolt and torque up to 100 lb-ft, you are just below 90% of proof load. I, I have a 2014 CC AT and based on forum feedback decided to check my rear leaf spring u bolts. Silikhan Publishing Group & GM-Trucks.com 0000015757 00000 n You said you were uncomfortable in the 70 ft. lb. Still did not solve my problem. 145 0 obj <> endobj 0000136057 00000 n My u-bolts were under torqued from factory. Metallurgy is what we do, calibration to spec is what they do. 0 Agreed, everyone has a solution, and at least people are leaning towards conservatism. 0000012306 00000 n I tightened my U bolts last night to 79 lbs. I get the same kit in on Friday for my 06 1500! I put the 3500 springs on and haven't noticed a big difference in the ride. Come join the discussion about duramax engines, performance, builds, modifications, classifieds, troubleshooting, maintenance, and more! I'm comfortable with the ones I have though. Like I alluded to earlier, torque requirements are an approximation for achieving a particular tension and stress in a stud / bolt. 0000014661 00000 n Not a member of the "club", not a self appointed "this or that", not a legend in my own mind.