Strut failing?

[Geodudes550]

I think my front passenger side strut is going bad but I can’t convince myself either way. I’ve been getting a bit of a vibration at 85mph and above from the front passy side.

All stock suspension with 32k miles on a 2018 GT premium.

I swapped the front wheels to make sure it wasn’t a wheel or tire issue and the vibration didn’t move so I’m confident I can rule that out. Next I put the car in stands and had a look. I don’t see anything obviously bent or out of sorts. I checked the strut and I don’t see any oil leaks. However, when I go over a speed bump with the windows down, I can clearly hear a hiss from the front right. Maybe it’s possible I don’t see any oil leaks because maybe that strut is bone dry? I dunno.

My old man suggested I do the push test, y’know push down on the car at the strut on both sides but I can’t really tell if there’s a difference. I can say that if I’m in the twisties, left turns don’t feel planted but right turns do which further leads me to strut city. If I turn left at speed, it feels like the car is diving to the right but if I turn right at speed, there is no feeling like that.

It’s been a while since I had an alignment so it’s possible the vibration is that, but I wanted to get some second opinions. My tires don’t look like they’re experiencing uneven wear so I’m further inclined to think it’s not alignment.

Ford dealer says it make take a week or two for them to get to it and of course I have to leave it there for some reason so I’d like to avoid a cycle of fixing this then fixing that and being without a car for weeks.

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[S550HPP]

Check that wheel tire pressure and the inside of rim to see if any weights have come off.as first step.

Any alignment shop incl the tire shop can check alignment as well as front control arms that have been known to wear out around 30K miles.

I would say the strut is the last thing that would cause vibrations unless the bearing I totally destroyed which is highly unlikely.

 

[robvas]

If you're not under warranty, don't bother going to the dealer

Go to a shop that does tires and suspensions and have them take a look

 

[Geodudes550]

Check that wheel tire pressure and the inside of rim to see if any weights have come off.as first step.

Any alignment shop incl the tire shop can check alignment as well as front control arms that have been known to wear out around 30K miles.

I would say the strut is the last thing that would cause vibrations unless the bearing I totally destroyed which is highly unlikely.

I know the tire pressures are good all around. I didn’t see anything that leads me to believe a weight fell off like an adhesive patch but it’s possible. The vibration thing hasn’t been a slow process getting worse, it came on suddenly so you might be right. I can have a look later and see if I missed anything.

as far as control arms go, what would I look for to know if they’re going bad?

Thanks for the reply.

If you're not under warranty, don't bother going to the dealer

Go to a shop that does tires and suspensions and have them take a look

I’m still under warranty with ESP so that’s why I want the dealer to look. If they say everything looks fine to them (to avoid paying for work) then I’ll have an independent shop have a look. Thanks for the reply.

 

[S550HPP]

The gradual onset is definitely key.

Might have a degrading tire structure...hit any holes or see any side wall inconsistency?

Retorqued wheel nuts?

To check control arms need to have it on a lift with a huge pry bar and check for play.

Easiest is to disconnect the ball joint end of the arms from knuckle and see if it moves freely and if some play (they are stiff when new). You will need some loctite and torque wrench to put it back to 85lb.

 

[Cobra Jet]

Upper strut mount can be going bad. It’s not unheard of and is pretty common with the S550’s.

When you had the car up on stands - did you test to see if a wheel bearing was bad? This is another very common failure point on the S550. People have even had failures with less than 3k miles on a new car…. If you didn’t test, put the car back up on stands - grasp the wheel at the 12 and 6 and rock it. Do the same at the 3 and 9, rock it again. Did you get any wiggle/wobble or great amount of movement? If so, it’s a bad wheel bearing.

Also with wheel bearing assemblies - they will groan or vibe more as speed increases and when the car leans into a curve/turn on the side that is bad.

 

[Geodudes550]

The gradual onset is definitely key.

Might have a degrading tire structure...hit any holes or see any side wall inconsistency?

Retorqued wheel nuts?

To check control arms need to have it on a lift with a huge pry bar and check for play.

Easiest is to disconnect the ball joint end of the arms from knuckle and see if it moves freely and if some play (they are stiff when new). You will need some loctite and torque wrench to put it back to 85lb.

It’s possible the tires are going bad. I’ve had them for a couple of years and there’s been a lot of driving over bad roads. Nothing huge comes to mind recently but the weather has been cold and I got lazy and parked it outside a few times so yeah, it could be a tire thing. I don’t have a lift to check the control arm like that but I’m headed to the tire and wheel shop in a bit to check balance so maybe they can give it a wiggle.

Upper strut mount can be going bad. It’s not unheard of and is pretty common with the S550’s.

When you had the car up on stands - did you test to see if a wheel bearing was bad? This is another very common failure point on the S550. People have even had failures with less than 3k miles on a new car…. If you didn’t test, put the car back up on stands - grasp the wheel at the 12 and 6 and rock it. Do the same at the 3 and 9, rock it again. Did you get any wiggle/wobble or great amount of movement? If so, it’s a bad wheel bearing.

Also with wheel bearing assemblies - they will groan or vibe more as speed increases and when the car leans into a curve/turn on the side that is bad.

I checked the wheel bearing a few months back and it was nice and solid but admittedly didn’t check when I had it up the other day. I’ll ask the tire shop guys to check it. Funny you mention wheel bearing. I bought a spare a few years ago when a new OEM one was on sale for $40 just in case after reading people on the forum talk about them going out. If it’s the wheel bearing, that would be cool because I already have the part at least.
Thanks for the reply.

 

[S550HPP]

Could just be tire flat spotting ....especially if frequency increases especially to speed.....

 

[Geodudes550]

Just jacked it up and there’s no wheel play. The strut boot cover though isn’t attached at top or bottom, just loosely sliding up and down. The strut rod is bone dry and I don’t see any oil leak. The yellow thing on the strut rod was also loose but I have no idea what that means. When I lowered the car, I heard a faint hiss not from the jack.

 

[Geodudes550]

Could just be tire flat spotting ....especially if frequency increases especially to speed.....

Maybe but I’ve been dailying the car for 18 months now. Before that it sat but I feel like a flat spot would’ve worn out by now. I have no idea if a flat spot is permanent.

 

[S550HPP]

That's a normal strut...probably a tire

 

[1 old racer]

The yellow thing on your strut is called a bump stop and it is normal

 

[Geodudes550]

Thanks for the help guys. Back from the wheel and tire shop and the verdict is the front tires need to be replaced due to separating. Alignment is good and they didn’t see anything wrong anywhere else.

 

[S550HPP]

Best possible outcome!!

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