Rear Sway Bar End-Link

[Scorpion8]

My 2006 has a broken rear sway bar end link. No problem, easy fix. But I look in Rock Auto's catalog and there are about 5-6 different "Styles", everything from what looks to be a long bolt with a sleeve to space the bushing off top and bottom, to some really fancy links. The Motorcraft ones are reasonably priced, but not sure they match what is currently installed.

What's the preferred end link from the group? Or is this a part where it's best just to go to NAPA or O'Reilly's and grab what they have?

 

[swshawaii]

Use the newer design Moog K700539 for the rear. Easier to install and much more durable poly bushings.
Moog will likely discontinue the older style shortly. Replace both, center sleeves must be the same length.

http://www.moogparts.com/pdf/proble...letin_213006_Sway_Bar_Link_Eng.pdf?download=1

 

[Scorpion8]

How about the Motorcraft MEF-139, as it looks more substantial than the Moog part? I don't like the way the Moog cinches-up with that screw-on top cap, as the thin walls would be under a lot of stress vertically during suspension action. What I can't tell is how the top nut on the Motorcraft unit attaches since it isn't shown. Just a high-strength nut?

 

[swshawaii]

You're replacing a broken OEM rear end link, correct? Ask most owners here,

I'd guess 9 out of 10 would use aftermarket. Explanation in the pdf above. GL

 

[Explorer_PL]

OEM lasted 75k miles on mine, Moog another 150k and still looks good.

 

[edwx]

Two of my original links broke....one front, and one rear. I just went with the cheap Advance Auto replacement, about 10 bucks or so.

 

[thebrakeman]

Use the newer design Moog K700539 for the rear. Easier to install and much more durable poly bushings.
Moog will likely discontinue the older style shortly. Replace both, center sleeves must be the same length.

http://www.moogparts.com/pdf/proble...letin_213006_Sway_Bar_Link_Eng.pdf?download=1

I noticed several years ago that I had 3 out of 4 broken (!), and replaced all 4 with these Moog problem solvers (purchased from RockAuto). Lifetime Warranty, with any needed replacements handled thru RockAuto as well.

The only issue is that they do not give good clear instruction (with the parts) on how to properly install. I had used a torque that I found in a shop manual (I forget, which turned out to be way too much. Within a few months, 1 of the fronts broke. The reason is that when you torque any endlink too much, it can no longer swivel as it's supposed to. It's locked to the swaybar, and ends up simply bending the rod itself, and the rod breaks. I called customer service (at Moog/Federal-Mogul) and they gave me the preferred method (see below). Installed free replacement and adjusted the others, and all is well.

Proper Installation:
1. Install with the wheels on the ground or equal size ramps, so the bar is in neutral position. If you must remove the wheels, be sure the jackstands keep both sides at the same height.
2. Install with the barrel-nut on the bottom. It does not matter for operation, but this will allow you to inspect periodically for loosening, and you can easily tighten if needed.
3. After components are loosely assembled, tighten the nut until you can no longer turn the center sleeve by hand.
4. Tighten the barrel nut 1 more complete 360-deg revolution. You're done. Do not worry about a specific torque.
5. The design of the nut will prevent loosening. But if you installed with the nut at the bottom, you can easily watch for loosening. Mine have stayed put, and a bit of corrosion probably has them locked in place by now.

 

[Scorpion8]

Yea, thanks. I got mine replaced, albeit without those directions above. Easy enough, and it rides a lot better. I did tighten the barrel nuts to an equal height on the thru-bolt. No "thunks" anymore.

 

[Scorpion8]

I would disagree with one part of Brakeman's instructions, which is how tight to adjust the barrel nut of the end link. A "single-turn" on mine wouldn't even have made contact with the poly bushings and thus would have allowed the swap bar to slap around on the end link. That's gotta lead to more premature failure than what I did, which was to tighten mine down until the poly bushings were snugly captured, but not to the point where the end link was going to be stretched under tension. Too loose and you stand the possibility of that barrel nut loosening under vibration.

 

[swshawaii]

The reason is that when you torque any endlink too much, it can no longer swivel as it's supposed to. It's locked to the swaybar, and ends up simply bending the rod itself, and the rod breaks.

This too. Bayonet or stem type end links should NOT swivel. Sway bar twists and puts opposing up or down force on the end links. As a test, mark the end links and LCA's and see if they "swivel" after some driving. Ideally, and if tightened properly, both end links shouldn't move or rotate at all.

the front suspension member of the outside of the turn gets pushed upward. The arm of the sway bar gets pushed upward, and this applies torsion to the rod. The torsion them moves the arm at the other end of the rod, and this causes the suspension on the other side of the car to compress as well.

How do stabilizer bars work?

 

[thebrakeman]

I would disagree with one part of Brakeman's instructions, which is how tight to adjust the barrel nut of the end link. A "single-turn" on mine wouldn't even have made contact with the poly bushings and thus would have allowed the swap bar to slap around on the end link. That's gotta lead to more premature failure than what I did, which was to tighten mine down until the poly bushings were snugly captured, but not to the point where the end link was going to be stretched under tension. Too loose and you stand the possibility of that barrel nut loosening under vibration.

Scorpion,
I suspect that we have done pretty much the same thing. But I think you misunderstood my step #3? Did you think I was talking about the barrel nut being hand-tight, then 1 more rev? Read again.
3. After components are loosely assembled, tighten the nut until you can no longer turn the center sleeve by hand.
4. Tighten the barrel nut 1 more complete 360-deg revolution. You're done. Do not worry about a specific torque.

You tighten the barrel nut into the bushings, while your other hand is monitoring the center sleeve. As long as you can still turn that sleeve, you are not tight enough. Once the components have clamped down enough, so that the center sleeve can't be turned with a gloved hand, THEN you turn the barrel nut 1 more rev, and you're done.

 

[thebrakeman]

This too. Bayonet or stem type end links should NOT swivel. Sway bar twists and puts opposing up or down force on the end links. As a test, mark the end links and LCA's and see if they "swivel" after some driving. Ideally, and if tightened properly, both end links shouldn't move or rotate at all.

Well, I disagree. There must be some angular motion between the link/bar and/or the link/arm (or whatever it attaches to on other vehicles. If there is no need for relative angular motion between these components (I called it "pivoting"), there would be a solid connection, with no need for bushings.

With the softer stock rubber bushings, it's the rubber itself that can easily compress, allowing for some relative motion, but that rubber will break down relatively quickly. But when you harden the bushing material, then clamp down too tight, that hard material can not "give". The slight angular motion that the link needs is directly transferred to the rod. The rod is very strong in tension and compression. But under this bending-fatigue load, it will break at 1 end or the other, which is exactly what happened with my 1st replacement.

When I spoke to the engineer at Moog/Federal-Mogul, he confirmed this, and gave me the recommended procedure. Perhaps the word "pivot" is not the right word. But the point is to prevent putting that rod into bending loading. To me, that means allowing the angle between the rod and the bar to change slightly as needed. With a stiff bushing like this, that means making the joint tight enough so that there is no clunking when 1 tire moves more than the other side. A strait load is directly transferred by the rod. But not so tight that it can not allow for small necessary rotations.

Going by torque alone is not reliable, since there are too many factors that could be affecting the torque. Using torque alone can end up having you too loose or too tight. The recommended procedure (like most joints in any industry these days) gives a sort of "torque and angle" procedure. The initial loading settles all of the components to a minimum compression (can't turn the sleeve anymore). Then the 1 rotation is a very controlled compression on the bushings (tension on the rod), equal to the thread pitch of the rod.