Broken swaybar sleeve bolts

SixBanger · May 14, 2019

Hi,

After driving for a while with the new polyurethane sway-bar bushings the steering performance is better than before.
But there is an problem with that after a speedbump one of the sleeve connection bolt just has broken off.
The bolts are 307A, grade 1, quality. So it is not the strongest bolt.

I get some grade 5 5/17 bolts. But am thinking why the bolts just broken after a while driving over speed bumps?

Can that be that the connection in the retainer link (to K-body) give to much friction? These are also new and have fit them with some silicone grease.
Or there is something wrong with the retainer link units.

Thanks!

Opticon77 · May 14, 2019

Those stock swaybars don't have end links to accommodate extreme control arm articulation (like over a speedbump) so the twist puts direct and uneven tensile pressure on the end bushings and bolts. If you upgraded the bushings that means more tensile pressure went into the bolt head.

Upgraded bolts should do the trick. Grade 5 will have double the tensile strength of your current 307a.

SixBanger · May 14, 2019

Okay good to see that mounting grade 5 bolts should fix the problem. Why didn't they sell in the first place 5 grade bolts? I mean, I am not the only one where the bolt has been broken?

Opticon77 · May 14, 2019

Factory bolts with the rubber bushings would never have seen that kind of load because the rubber end bushings soak up the slight changes in angle as the control arms reach its extents.

Or were the bolts new with the polyurethane kit? If so what brand?

Opticon77 · May 14, 2019

Look at how much angle that eyelet on the end of the bar has in between the two endlink washers (right side of photo)...

If you push that control arm any higher (lower the car and/or hit a bump) that eyelet is going to be spreading/prying at the washers. Stiffer bushings would only help it pop the head of that bolt off like a bottle cap. This is why aftermarket sway bar kits add a proper end link.

SixBanger · May 22, 2019

Thanks Opticon77.

I had to say that I first replaced the worn rubber with an poly set of ENERGY SUSPENSION. Bolts were also supplied with this kit (I have checked, grade 5).
But after a few months, one apparently broke. In the first instance I assumed that it had been come lose.

Then I have replaced for the left side with an Moog set (307A bolt).

Now I can image that the stiffer poly bushings can stress the bolts more.
But with the fresh poly bushings I did have some 'issues' to install the new bolt. First I did install the retainer links to the K-frame and Then the the sleeves. Doing this way I only get sleeve on one side install easy, the other side (right) give some problem. I had to push the sway bar up to the torsion bar to install the other bolt (2 inch ish).

I did check and measure the different mounting places. It seems like that were no big difference.

But the strange the next thing did result in a better installation.

Now I did install and torque down the sleeves before I mount and torque the retainer links. The strange thing was that it was now installed without any difficulty. And probably there should now less tension on the bolts. But we'll just see it.

SixBanger · Nov 7, 2019

Yesterday the confirmation of the left sway bar with the front suspension failed. The bolt with rectangular nut is torn through the piece of steel from the front suspension (torsion bar mount).
Maybe the steel is to thin. I think this could be the the bad roads I rode last summer. If possible I can weld this again and reinforce it with a thicker plate.

But has anyone had this before in combination with poly bushings?

volare 77 · Nov 7, 2019

how much are you really gaining with poly bushings. I would put rubber back in and be done with it.

SixBanger · Nov 7, 2019

Ehm that is not a bad idea. Rubber ones are gone and was a very lose old ones. I would see if there are rubber 1" ones for sell.

volare 77 · Nov 7, 2019

moog-k7087

Duke5A · Nov 7, 2019

SixBanger said:
Yesterday the confirmation of the left sway bar with the front suspension failed. The bolt with rectangular nut is torn through the piece of steel from the front suspension (torsion bar mount).
Maybe the steel is to thin. I think this could be the the bad roads I rode last summer. If possible I can weld this again and reinforce it with a thicker plate.

But has anyone had this before in combination with poly bushings?

Do you mean this part is trashed?

If so, you're not going to be able to fix that - at least not with the torsion bar in the car. Even then you'll most likely damage the bushing applying any heat to that to fix the shell. You're going to have to replace the torsion bar bushing.

Or did that flat piece of threaded steel that slips into the pocket that the end link bolt threads into just brake? That's easy and those damn things break all the time.

I hope I read that wrong.

AJ/FormS · Nov 8, 2019

If you split the Poly bushings, Either something is amiss in the install or;
the front ride height is too low,
the shocks are cooked,
or you're a heck of a corner-stuffer, and in need of bigger T-bars;
and I want a ride.

If your ride height is too low,then in the corner, the outside LCA will sit on the bumpstop, and turn pretty good. But the inside wheel will drop down and twist thechit out of the anti-roll bar, and put a huge force on the links, both ends. Oh do I feel sorry for them if you hit a bump midturn, cuz there is no suspension left on the outside wheel, and the inside wheel is just sorta hanging there, catching some Zs.
I used to be set-up like that, cuz it really does corner pretty good; rough as heck but turns real nice. But it was just too hard on parts.

SixBanger · Nov 11, 2019

The broken part is what Duke showed in the picture.
Front ride height is on spec or some higher. Shocks are replaced last year. Only thing I can think of are the bad roads that I did drive last summer, and a round across the Nurburgring Nordschleife ... And on a usual trip here I have to take some corners. And speed bump country here.

Duke5A · Nov 11, 2019

Well, the piece in the photo is a spare I have and I only have one. Kinda useless... If you can't find one that side of the pond I can ship this to you for the cost of the ride. Last time I shipped something to Europe it was a quarter class for a 78 Diplomat. I was able to declare it a gift since I didn't charge the guy and he got out of having to pay VAT.

SixBanger · Nov 12, 2019

Thanks for the offer. First I will try to spot weld it with some coolant. Replacing would be necessary anyway if bushing get to hot. Other I would just weld the entire swaybar construction to the torsion bar mount, don with the prone of failure bolt mount construction.. If I remember me, the left one, not the broken one, has been replaced before with some bigger sheet metal.

BudW · Nov 12, 2019

Can you take some pictures of your breakage.
I hear what you are saying but just can't picture what you said did break.

SixBanger · Nov 13, 2019

Here a picture of the broken connection.

However, I wonder why the swaybar has such a great distance when it is not mounted. So when you mount it, it is already on some pre-tension (car is on both sides with a flat road).

Duke5A · Nov 13, 2019

It honestly doesn't look like there is anything wrong with it. It's just assembled incorrectly. That piece of flat stock steel that the bolt threads into is supposed to slide into the pocket on the torsion bar bushing and then the bolt gets threaded in.

This all is to be done with both wheels on the ground.

SixBanger · Nov 13, 2019

Ah right. Maybe it is not good to see on picture. But the steel between flat stock steel is just gone. I assume torn off.

Perhaps it is an option to increase the area of the mounting position. Given that he only clamps a little bit with the current torsionbar mount and square plate. In addition, there is a large hole at the position of the bolt.

Duke5A · Nov 13, 2019

That is crazy...the pocket is made up of some very thick steel for what it is. I would think the threads would give way before anything else.

Well, that torsion bar end is yours if you want it. Good luck.

Broken swaybar sleeve bolts

Well-Known Member

Well-Known Member

Well-Known Member

Well-Known Member

Well-Known Member

Well-Known Member

Well-Known Member

Well-Known Member

Well-Known Member

Well-Known Member

Well-Known Member

Well-Known Member

Well-Known Member

Well-Known Member

Well-Known Member

Moderator

Well-Known Member

Well-Known Member

Well-Known Member

Well-Known Member