Smart Strut Update
Thread Starter
Team Owner
Joined: Jun 2001
Posts: 23,367
Likes: 1,061
From: Virginia USA
Smart Strut Update
With all the treads about Smart Strut jamb nuts coming loose I decided to e-mail VBP and ask what they recommend to keep this from happening. I am sure that they have heard about this before but want to know what they say. I'll keep you guys/gals posted on what they recommend and if they plan on fixing it. This seems to be a major design flaw to me.
Instructor
Joined: Dec 2001
Posts: 196
Likes: 0
From: Dry Ridge Kentucky
I'm definately interested. I've been the originator of some of the threads.
Readjusted mine yesterday and smoked the jam nuts down with some locktite. Gonna drive it today for a while and see what happens.
Readjusted mine yesterday and smoked the jam nuts down with some locktite. Gonna drive it today for a while and see what happens.
Team Owner
Joined: Jul 2004
Posts: 40,352
Likes: 787
From: Redondo Beach, California
Me too! I wonder if just something like a lock washer between the nuts and the strut rod would work. I've read comments about just really torquing the nut down really tight. I'd like to know if there's a torque (foot-pounds) recommendation. To measure torque, you're going to need a crow's foot wrench end for your torque wrench. With the size of the nut, the crow's foot wrench fitting will be a little pricey.
..About torqueing things down really tight. When I was perhaps 20 years old, I got a job working as a lab technician at Aeroquip Corp in Jackson Michigan. One of my first jobs was to take assembly line produced aircraft stainless steel hydralic lines, torque them into a manifold and pressure/temperature cycle test them. If tight was good, extra tight is better ..right? As a beginning technician, I tighten my first assignment of hoses up as hard as I could. It was a little bit later that I found out that I had destroyed them all by overtorquing them. I don't know what the dollar amount really was , but I think it was a lot of money. I've been a little bit gunshy about overtorqueing ever since then.
..About torqueing things down really tight. When I was perhaps 20 years old, I got a job working as a lab technician at Aeroquip Corp in Jackson Michigan. One of my first jobs was to take assembly line produced aircraft stainless steel hydralic lines, torque them into a manifold and pressure/temperature cycle test them. If tight was good, extra tight is better ..right? As a beginning technician, I tighten my first assignment of hoses up as hard as I could. It was a little bit later that I found out that I had destroyed them all by overtorquing them. I don't know what the dollar amount really was , but I think it was a lot of money. I've been a little bit gunshy about overtorqueing ever since then.
Melting Slicks
Joined: Apr 1999
Posts: 2,010
Likes: 3
From: Moon Twp. PA USA
Is it really the jam nuts coming loose? I had mine aligned this past fall. Watched the mechanic put loc-tite on the nuts, per my instructions. After a couple of drives, I noticed the top of one rear tire was tilted in. Crawled under to check and found the nuts were still loc-tited in position. The sleeve itself had worked its way loose. Since the nuts were still tight, I cleaned the exposed threads between the nuts and the sleeve and applied loc-tite to these threads.
I've only had it out a couple of times before winter storage, but that seems to have done the trick.
I've only had it out a couple of times before winter storage, but that seems to have done the trick.
Melting Slicks
Joined: Oct 2004
Posts: 2,662
Likes: 8
From: Knoxville Tennessee
As this is one of the upgrades I plan on doing, it worries me that this should be such a problem. Could you possibly take the nuts, drill a couple small holes in the sides and lockwire them in place once the adjustments are complete? I have done this thousands of times on airplane engines.
Instructor
Joined: Jul 2004
Posts: 189
Likes: 0
From: Orlando Florida
i would like to suggest if using Loctite , first use the primer.also what # are you using 242 is good for general thread locking, but it is designed for the part to be removed easily. if you are sure of your adjustments and need no more tweeking i recommend #'s 620 or 680.they are identified by a green color(242 is blue, thread sealers are red). once applied they will definately stay put. the 620 sometimes takes a bit of heat to help break it loose.
My 02
My 02
Le Mans Master
Joined: Nov 2004
Posts: 7,186
Likes: 45
From: detroit area
if you really think about it, the sleeve could untwist from the nuts..... vision it.... in order to camber in/out the wheels it takes either a clockwise or a counter clock wise motion....now once the nuts are tightened, the sleeve will technically only stay put in one of the motions...clock or counter clock...... is is very possible for the sleeve to work itself from the nuts and untwist the rods therefore having the tires bow out at the bottom....... also with the weight, vibration, and cornering of the car this will also help in working the sleeve loose.... it would almost be pratical to set screw the sleeve to the threads...that's an idea.......maybe that would help.....weld a nut or just tap a hole in the sleeve and use a machine screw to lock it in place.......
b
b
Thread Starter
Team Owner
Joined: Jun 2001
Posts: 23,367
Likes: 1,061
From: Virginia USA
Originally Posted by BerniesVette
As this is one of the upgrades I plan on doing, it worries me that this should be such a problem. Could you possibly take the nuts, drill a couple small holes in the sides and lockwire them in place once the adjustments are complete? I have done this thousands of times on airplane engines.
Bernies
I am an A&P also and thought about safety wiring the too. I know you have seen the rod end washers with the small safety wire tabs. I asked VBP why they don't machine a groove in the treaded part of the rod end so it will accept these kind of washers. I am changing my front springs this weekend then getting a 4-wheel alignment so I am hoping for a solution before my alignment. Lock tite is an option but I would still worry about them and would constantly check them regardless. Safety wire is the only option that I would not worry about.
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I'm thinking maybe a tab washer and also .32 safety wire, your box is on it's way.. seeya
Instructor
Joined: Apr 2004
Posts: 161
Likes: 0
From: Grand Island NY
Posted this on the other thread. I have the complete VB suspension package and am worried about this situation happening. I’m going to saw a slot in the female adjuster and install a clamp like a stock steering tie rod end. The force of a jam nut on VB system only contacts the small area at the end of adjusting sleeve. A tie rod end type clamp has much more area to clamp on to the adjusting threads, and has worked well for many years on steering systems.
C6 the C5 of tomorrow
Joined: Nov 2000
Posts: 6,665
Likes: 2
From: Twin Cities Minnesota
I don't understand.
I don't have the smartstruts, I have Guldstrands Heim jointed rods. When I lock them down they don't move. Not in like 5 years. Torqued to 100 ft lbs, I don't see how they could loosen on their own...
I don't have the smartstruts, I have Guldstrands Heim jointed rods. When I lock them down they don't move. Not in like 5 years. Torqued to 100 ft lbs, I don't see how they could loosen on their own...
Melting Slicks
Joined: Feb 2001
Posts: 3,330
Likes: 13
From: Europe , Luxembourg
Hi
When I installed them first, one nut came loose, so no misadjustment happend as the other side's nut was still preventing the sleeve rod from turning.
I retorqued all ( as hard as possible ) and OK for last 2 years now.
I guess, due to grease and other stuff on the threads, the first torquing might not be sufficient. I suggest to drive a bit to get the whole car's weight to settle the threads, than retorque again.
Of course, safety wire should do, but again, you will not notice a loose nut untill the wire gives up.
The same counts for spreader bars etc. First torque is not good enough as final.
Rgds. Gunther
When I installed them first, one nut came loose, so no misadjustment happend as the other side's nut was still preventing the sleeve rod from turning.
I retorqued all ( as hard as possible ) and OK for last 2 years now.
I guess, due to grease and other stuff on the threads, the first torquing might not be sufficient. I suggest to drive a bit to get the whole car's weight to settle the threads, than retorque again.
Of course, safety wire should do, but again, you will not notice a loose nut untill the wire gives up.
The same counts for spreader bars etc. First torque is not good enough as final.
Rgds. Gunther
Tech Contributor
Joined: Aug 1999
Posts: 15,154
Likes: 3,959
From: Connecticut, USA
ok so where is the advantage over the stock rods with a rebuilt rear suspension? I install new rubber bushings in straight rods and have the rear aligned, no problems? I think we over engineer things sometimes, buy hey what do I know 
Gary
Gary
Melting Slicks
Joined: Mar 1999
Posts: 2,845
Likes: 2
From: Apex NC
Originally Posted by gtr1999
ok so where is the advantage over the stock rods with a rebuilt rear suspension? I install new rubber bushings in straight rods and have the rear aligned, no problems? I think we over engineer things sometimes, buy hey what do I know
Gary
Gary
Melting Slicks
Joined: Feb 2000
Posts: 3,050
Likes: 9
From: Fairport NY
Originally Posted by sb69coupe
Gary, I couldn't agree more. With all the rear end components within spec, why does anyone need this additional complicated piece? I have read the claims of "increased range of adjustment" and such, but I just don't see any advantage os using them on a street driven Corvette.
Le Mans Master
Joined: Oct 2004
Posts: 5,269
Likes: 54
From: Orlando Florida
St. Jude Donor '05
Originally Posted by sb69coupe
Gary, I couldn't agree more. With all the rear end components within spec, why does anyone need this additional complicated piece? I have read the claims of "increased range of adjustment" and such, but I just don't see any advantage os using them on a street driven Corvette.
When upgrading to poly bushings - why leave the old strut rods installed ? The adjustable rods are less than $100 including the bushings... they seem to be stronger and look nice and shiny
The nuts must be torqued and glued with Locktite or similar product, otherwise they will come loose....
Team Owner
Joined: Apr 1999
Posts: 21,953
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From: Reno Nevada
2024 C3 of the Year Finalist- Modified
Smart struts limit camber change over the full verticle travel of the wheel.
they also do a good job of holding the trailing arm in place if you have to drive home with only one half shaft.
they also do a good job of holding the trailing arm in place if you have to drive home with only one half shaft.
Safety Car
Joined: Oct 1999
Posts: 4,101
Likes: 10
From: NorCal
Improved geometry...
Originally Posted by gtr1999
ok so where is the advantage over the stock rods with a rebuilt rear suspension? I install new rubber bushings in straight rods and have the rear aligned, no problems? I think we over engineer things sometimes, buy hey what do I know
Gary
Gary
I was also considering safety wire. I believe it's the lateral loads that are somehow loosening the sleave. I'm no engineer, but I'm guessing it has something to do with thread pitch? I tightened the bejesus out of mine and it seems to be OK, but I check them often!
Hans
Race Director
Joined: Dec 1999
Posts: 16,945
Likes: 9
bump steer? There's no bump steer affected by the revised bracket, toe is not changed, the toe change curve is a result of the trailing arm hinge point and the 1/2 shaft, all that is affected by the smart strut + bracket is the camber curve,
Race Director
Joined: Mar 2001
Posts: 11,322
Likes: 1
From: Living in the Hartland
I think Zwede came up with the reason why the loose, he posted in another thread http://forums.corvetteforum.com/showthread.php?t=968987 the struts twist as they travel through the trailing arms motion, this twisting must break them loose over time unless realy torq'd down. Wonder if a heim joint (as 427V8 mentioned) can be added to one end to eliminate the stress from the twisting? I have a set and might look into it before I install them.
Edit Guess he was referring to the TA twisting but I think the strut would also twist as the TA moves since it moves in an arc.
Edit Guess he was referring to the TA twisting but I think the strut would also twist as the TA moves since it moves in an arc.
Last edited by Fevre; Dec 14, 2004 at 04:53 PM.