Spring Clamps Reduce Rear Vibration

BO TIE 1 · June 17, 2016

This will probably be my last post here.

Here's the end of my story. Dealer two couldn't get GM to do anything but gave me the name of a local shop that specializes in suspension and "lifts". (Boise Spring Works). They make their own U bolts, cold rolled. So quick trip to see what they thought and while talking to them they said that they didn't have access to stock for grade 8 bolts below 5/8" but that they torque their 9/16" grade 5 to 125#'s. Perfect!!! Thinking I would get hosed I told them to do mine, they had me back into the shop and went to work.. They removed the existing U bolts to find that the 9/16" would fit without any modifications. I also had them remove the spring clamps noted in a previous post. One guy built the U bolts while another removed the existing.15 minutes later they gave me a bill for less than $40. About like stopping for gas and far less $$ installed than I could buy anywhere. Not often that cost and service both exceed expectations in my world.

So thinking I would go back to them next week for new shocks, I did some quick testing. My suspension works the way it should now. RR tracks and other bumps are so much smoother, best riding truck I have ever owned. And now my drivetrain has tightened up. I was getting some slop on and off the gas and that is almost completely gone. I assume the loose U bolts were allowing "axel roll".

I'm so happy with my truck now that I ordered a tune from Black Bear.

And for those guys switching to Ford..... The shop guys told me several stories about Ford aluminum panels tearing, bed damage on a couple with $3000 repair tab. You don't fix aluminum, just replace it. According to them, GM is bad but Fords are worse and very costly to repair. And they have been adding another leaf spring to some Fords because they built them too light. I always take these kind of discussions lightly but just sayin!!!

Anyone that wants to try heavier U bolts-look for a local "spring works" business that specializes in lifts and builds springs and suspension parts for classic cars. Even if it cost triple it's worth it, IMO.

Have you had it up to the magical 70 mph limit yet? Any vibes?

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Ron.s · June 18, 2016

Have you had it up to the magical 70 mph limit yet? Any vibes?

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Yes, no vibes. Actually mine only vibrated on rough roads at 75-85. But I could fell it kind of "quiver" at lower speeds and Magneride shocks weren't working. The rougher the road the worse it got but no vibe on smoother roads. I call it suspension failure vibe vs rotational out of balance vibe.

j13smiley · June 18, 2016

Can they build more u bolts and ship them?

Ron.s · June 18, 2016

Can they build more u bolts and ship them?

I don't know but here's the contact info:

Boise Spring Works

800-585-5332

boisespringworks.com

The bolts are 9/16" X 8 1/2" X 2 1/2". The price was $9.69 each.

They wrote up the invoice 9/16" X 20" U bolts 2 1/2" and something I can't read, maybe 54. I assume that 20" is the total bolt length. If any confusion I'd be happy to drop back by, but tell them I had the red 2016 GMC on Friday about noon.

JimmyJ_123 · June 18, 2016

I put the Pro comp 2 in blocks with there U bolts. The bolts are heavier grade. The vibration at any speed is gone.

BO TIE 1 · June 19, 2016

I put the Pro comp 2 in blocks with there U bolts. The bolts are heavier grade. The vibration at any speed is gone.

How many foot lbs. Of torque did you tighten them to?

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Jeff5347 · June 23, 2016

I'm amazed. I just added the spring clamps you guys mentioned from advance auto and the ride is..smoother. How the heck is that. It was bad before as a full frame vehicle is stiffer than a unibody so I know it wouldn't ride like a caddy or anything..but added the clamps and wow. Only got to drive about five miles but the set of train tracks I usually hit proved it. Much softer going over them. Tomorrow is the hiway test. Def hope this helps the vibs at 70 I get

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jagabom (Esquire) · June 27, 2016

Ron.s, are the bolts still at 25 lbs final torque?

Jim

Ron.s · June 28, 2016

Ron.s, are the bolts still at 25 lbs final torque?

Jim

They torqued mine to 125# and I haven't checked them again.

ToesonTheNose · June 28, 2016

https://www.facebook.com/groups/1511758879066581/permalink/1765114533731013/?comment_id=1765145130394620&reply_comment_id=1765172030391930&notif_t=group_comment_reply&notif_id=1467132445714986

This guy is saying he's a tech and that doing level kit 1.5 inches is fixing the shakes. Any thoughts

Vic15 · June 29, 2016

https://www.facebook.com/groups/1511758879066581/permalink/1765114533731013/?comment_id=1765145130394620&reply_comment_id=1765172030391930&notif_t=group_comment_reply&notif_id=1467132445714986

This guy is saying he's a tech and that doing level kit 1.5 inches is fixing the shakes. Any thoughts

Geometry?

afireinside7444 · July 8, 2016

I tourqed my factory u bolts to 70lbs last night (were about 40) drove on a 1 week old brand new concrete freeway I 275 SB here in Michigan. It is 80% better instead of 70 to 85mph its around 75 to 79 and reduced quite a bit in intensity. When i got to work i tourqued them to 80lbs. Lets see if i have more change.

Edited July 8, 2016 by afireinside7444

NH_Silverado_6.2 · August 20, 2016

This will probably be my last post here.

Here's the end of my story. Dealer two couldn't get GM to do anything but gave me the name of a local shop that specializes in suspension and "lifts". (Boise Spring Works). They make their own U bolts, cold rolled. So quick trip to see what they thought and while talking to them they said that they didn't have access to stock for grade 8 bolts below 5/8" but that they torque their 9/16" grade 5 to 125#'s. Perfect!!! Thinking I would get hosed I told them to do mine, they had me back into the shop and went to work.. They removed the existing U bolts to find that the 9/16" would fit without any modifications. I also had them remove the spring clamps noted in a previous post. One guy built the U bolts while another removed the existing.15 minutes later they gave me a bill for less than $40. About like stopping for gas and far less $$ installed than I could buy anywhere. Not often that cost and service both exceed expectations in my world.

So thinking I would go back to them next week for new shocks, I did some quick testing. My suspension works the way it should now. RR tracks and other bumps are so much smoother, best riding truck I have ever owned. And now my drivetrain has tightened up. I was getting some slop on and off the gas and that is almost completely gone. I assume the loose U bolts were allowing "axel roll".

I'm so happy with my truck now that I ordered a tune from Black Bear.

And for those guys switching to Ford..... The shop guys told me several stories about Ford aluminum panels tearing, bed damage on a couple with $3000 repair tab. You don't fix aluminum, just replace it. According to them, GM is bad but Fords are worse and very costly to repair. And they have been adding another leaf spring to some Fords because they built them too light. I always take these kind of discussions lightly but just sayin!!!

Anyone that wants to try heavier U bolts-look for a local "spring works" business that specializes in lifts and builds springs and suspension parts for classic cars. Even if it cost triple it's worth it, IMO.

Hey guys, I just bought a 2016 LTZ Midnight (Z71). 40 to 80MPH vibe issues. Had the roadforce balancing which helped, but still randomly vibrating 40-80. Also have horrible roadhop around this corner that my 2011 would take no problem.

I'm curious about the missing rear spring clamp. I just checked mine and it does not have rear spring clamps either. I'm wondering if this is causing a slapping vibration. Did anyone try adding those extra clamps in where a rear clamp would typically be?

Does anyone with a 2014-2017 Silverado/Sierra have rear spring clamps installed from the factory?

NH_Silverado_6.2 · August 22, 2016

So I did some more research at the dealer. I looked at a bunch of 2016 Silverado's and one 2017 Denali. None of them were max trailering. None of them have a rear spring clip. I still think this could allow spring slap. But could that cause a resonance?

Also found this really good site on springs and clips. It says that your spring clip should have a gap above the spring and on sides to allow the springs to slide. Maybe it is less critical to slide if clamp is located near the U-bolts.

http://www.suspensionspecialists.com/tech0004.html#9

No spring clips yet and my vibes seem to be less when Duratrac tires are at 35PSI on hot day (85-90F).

Sir Dan · August 30, 2016

Reluctantly, I'm joining this thread since I just returned from my first long interstate trip and the shaking was un-mistakable above 70mph. Grrrr! Apparently, it's such a common problem that it's known as the "Chevy Shake" all over the internet!

http://news.pickuptrucks.com/2016/06/mysterious-chevy-shake-brings-much-frustration-few-solutions.html

Hoped I hadn't gotten a vibrator but alas, here we go. Had the dealer check tire balance and did find all 4 were off by .5 -.75 oz Somewhat smoother but still does that weird constant wobble/hop thing on any mildly uneven pavement over 70 mph. Ubolts maybe a little loose? Tq'ed to 79 ft/lbs ..no change. Are people that have upgraded the stock Ubolts to heavier ones still having good results?

Edited August 30, 2016 by Sir Dan