3 Front Control Arms Replaced at 40K Miles

[Grimmer]

Is this a normal issue for the S550? (2016)

I have had to replace the driver side lower rearward, passenger side rearward and forward control arms at only 40K miles.

The driver side rearward went first. I figured perhaps a marginal part from the factory, but then the passenger sides went too. The odds of just a defective control arm drop significantly when 3 of them are toast. I specifically checked the passenger side when I replaced the driver side... No slop. Within a few months both the passenger side lower control arms went sloppy.

My car has had the issue of sticking unwind when conditions are just right after a left hand turn. Not sure if they are related, but hopefully it won't be eating control arms all its life. I had hoped the first replacement would cure that too but I didn't.

I've used Motorcraft replacement parts, we'll see how well they hold up. If it doesn't go well, any advice on what can be done to cure its hunger for control arms?

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[DansFLHTI]

Thanks for posting this.I never knew how to explain the issue with my 2016 GT Convertible until I read "sticking unwind" in your post.My car does this occasionally on a right turn and I have a slight clunk sometimes which appears to be in the right suspension.

 

[Grimmer]

There have been a few threads about that. Several people have had this issue, although not too widespread. To my knowledge, the cause hasn't been identified. There are a few that said multiple alignments eventually cured it; whereas alignments haven't helped others. Some have had at least one replacement power steering unit to correct it.

I've had mine to the dealership a couple of times and they always said that they couldn't replicate it. Although, it was happening often enough that had they just gone around the block several times always turning left they should have certainly encountered it.

At first I thought (or hoped) that there was simply a burr on the steering gear that would eventually wear in... no such luck; it still does it. Another thought is that the steering and suspension geometry is just a tiny bit off from normal and when the steering is in just the right position with just the right amount of load on (or off) that geometry, there is just enough bind to prevent it from getting started on the self-unwind. If I help it a little bit, it will unwind on its own from there.

I have never had it do that when turning right. And I believe that the majority (if not all) of the cases posted have also had it in only one direction.

 

[Grimmer]

I have driven with the 3 new control arms for a couple of weeks.

When the first one (driver rearward) went out, I don't recall noticing much being off with the handling. I discovered it while checking for wheel bearing / steering slop when putting on the summer tires (I give all 4 wheels a healthy shake left-right and top-bottom when I switch the tires twice each year).

As mentioned previously, I figured it was just a fluke and only replaced that one, I noticed a few months later that whenever the nose settled after a hard pull, it would tweak the car to the left. The farther the nose settled, the more pronounced the jig to the left (even rotated the steering wheel a skosh).

I lifted up the front end and checked for slop again and found both of the passenger side control arms were thumping with the left-right tire shake. For all three of these control arms it was the ball joint end that was loose, floppy, and had up-down play. I didn't see an option to replace just the ball joints. Perhaps I need to look harder for those specific ball joints being sold by themselves? Any body know for sure if they are the same as the other ball joints? Similar to the driver's side, I replaced the whole control arm for both forward and rearward on the passenger side. The leftward tweak when the nose settled was cured by the new control arms.

I am planning to replace the remaining driver's side forward control arm just as a matter of good practice, so I have not had the alignment checked or reset yet. There is a little twitch when pulling hard (nose rising / nose up) which may be from the lack of alignment, but most likely the remaining control arm is starting to loosen up.

Here is where it gets interesting ... and I don't want to jinx it ... but I have not noticed the "left turn sticking unwind" phenomenon occurring since those were replaced. It is unlikely that the control arm wear was the root cause of the sticking unwind since it has been sticking from day one when they were most certainly not worn / loose. In the service manual, it instructs that the control arm frame side bolt should be tightened & torqued with the car's weight on the tires at the normal ride height. So my best guess so far is that some or all of my frame side control arm bolts were initially secured just a little bit off from where they should have been. I could be completely wrong about that, and maybe when the last remaining control arm is replaced and the alignment is set, that sticking unwind might return.

I also had to cheat a little bit to follow that instruction. I cannot get the car off the ground high enough, and still have its weight on the tires, to swing my long 250 lb-ft torque wrench, or even my shorter 150 lb-ft one without hitting the ground or frame or something. For the driver's side I had the car lifted high with the tire removed and used a bottle jack on the knuckle to pre-load the strut to what I estimated was the normal ride height. For the passenger side I used drive-on ramps but had to tighten the frame side bolts as much as possible with a shorter tool, then lift the car high off the tires to finish the final 184 lb-ft torque with the long torque wrench. Wouldn't it be nice to have a portable lift! I could even use it to get the car up to a more manageable height for washing and waxing instead of groveling around on the ground at ankle height.

One other thing to note...
The service manual also instructs that the control arm nuts and bolts should be discarded and not reused. I didn't have any on-hand and the new Motorcraft control arms didn't come with them (if new ones are required, shouldn't they be supplied?), so I did the "unthinkable" and reused them (at least temporarily). The ball joint nuts are only torqued to 84 lb-ft, so I don't see why they would need to be replaced. The frame side bolts are 184 lb-ft, so perhaps they are legit stretching and really do need to be replaced. Although they are large diameter bolts (14mm+ but I didn't measure) and should be able to handle that much torque). Any opinions on the need to replace them? Funny thing... RockAuto sells the nuts, but not the bolts. I'll probably have to get the bolts from the dealer parts counter - assuming I can find them in-stock around town. Preliminary searches showed the bolts at around $17 each and the nuts around $6 each.

Edit: a complete set of nuts and bolts (2x forward bolt, 2x rearward bolt, and 4x nuts) was only $25 at the local parts counter.

 

[ChiTownStang26]

Having the same issue on my 16, control arm passenger side rearward. Car off the ground has a good amount of wiggle in the wheel plus certain angle banked turns causes wheel whobble so I bought the steeda ones.

Was it easy to get off? No ball joint press or special tools needed?

I'm building a wheel cradle out of 2x6s to clock those bushings

 

[Grimmer]

My standard kit of suspension tools worked fine to press the ball joint taper out of the hub for the rearward control arm. However, on the forward one none of them were big enough to reach over the bolt and the claw type had nowhere to grab. I couldn't find any suspension tools locally that were any bigger and the Ford tool is quite pricey. So I had to use one of those wretched fork tools and a hammer to get the forward ones out.

I haven't been able to find a replacent ball joint for those control arms. As far as I can tell the bushing side (which are sold separately at RockAuto) were just fine. Would have been nice to press out the ball joint and press in a new one. It would have saved a bunch of $$$. The dealer parts diagram doesn't list the ball joints separately. Maybe there is a way to confidently match them to other ball joints that Ford uses and does sell separately.

I did get the alignment done this weekend. It feels nice and straight again. So far no wiggles or twitches. Also seems to have cured the left turn sticking unwind issue, although it may be too soon to tell. Hopefully that is gone and hopefully took the early control arm wear with it.

 

[ChiTownStang26]

Well luckily I'm doing the rearward (lateral link) then and by standard sus kit I hope your referring to a mini 9lb sledge with a sideorder of brute force otherwise I'm going to need some clarification lol

I didn't give much look into replacing just the ball joint because I've been wanting to replace them with the Steeda's Lateral Link (555 4906) for some time now. Try asking BmacIL about that, dudes a suspension guru IMO

 

[Grimmer]

This type of thing...

https://www.summitracing.com/parts/pwb-648626

Basically boils down to a ball joint or other type remover / puller that can grab onto the hub and press on the "bolt".

The Ford tool looks kind of like the one on the bottom but is quite a bit longer.

 

[MidnightStars]

Looks like I'm not alone. Went for an alignment after having wheels installed, and they noticed that my front two (lower?) control arms are shot at 50k miles.

Thinking of getting the Ford Performance options. I've seen people online replace them with just a breaker bar and an impact. Not sure how well I'd be able to replace the bushings alone, never ever did anything like that before

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