Rear End Loose Feeling

[slow3v]

Hi all,

We have a 2018 Expedition that recently has started to exhibit an odd handling characteristic. The rear of the car is behaving differently, and I can't figure out if it's tires or what. At highway speeds, the car seems VERY eager to turn-in and responds to very little steering input (i.e. when taking a sweeping curve). It seems that the rear end feels loose, or not planted - almost like it wants to wag back and forth. I have noticed this while towing and it seems to feel the same way unloaded, now.

There are no clunks, knocks or creaks - something I'm very in tune with. I am going to have the alignment checked, and the suspension itself feels fine - no floatiness over bumps/rises/dips, but it just feels... off. Has anyone else experienced this?

Thanks
Nick

 

[99WhiteC5Coupe]

Hi all,

We have a 2018 Expedition that recently has started to exhibit an odd handling characteristic. The rear of the car is behaving differently, and I can't figure out if it's tires or what. At highway speeds, the car seems VERY eager to turn-in and responds to very little steering input (i.e. when taking a sweeping curve). It seems that the rear end feels loose, or not planted - almost like it wants to wag back and forth. I have noticed this while towing and it seems to feel the same way unloaded, now.

There are no clunks, knocks or creaks - something I'm very in tune with. I am going to have the alignment checked, and the suspension itself feels fine - no floatiness over bumps/rises/dips, but it just feels... off. Has anyone else experienced this?

Thanks
Nick

Have you checked the tire inflation and is it set to Ford’s cold inflation PSI?

Stock wheels? Stock size tires?

What is the tread depth of the tires?

 

[JasonH]

It's possible the rear struts are done. Find a bump or dip that compresses the rear suspension. If it pops up aggressively then you may need rear struts.

 

[slow3v]

The struts feel fine over dips and dives at highway speeds, though I suppose they could be worn. Visually, all looks OK. I will have to get underneath and pull on some stuff, and have the dealer check the alignment.

It's almost like the initial turn-in is too aggressive. You turn in, then the weight/body shifts, and as the vehicle sets into the corner it almost turns in more.

Stock wheels, stock size Firestone Destination LE3, ~7/32.

 

[DieselMonk]

Sway bar on the rear? Bad shocks?

 

[Moeman]

It seems like you and some others are onto the right things to check - tires (rotate to see if it changes the behavior??), shocks, sway bar bushings and links. Get the rear end raised. Try moving all of your suspension parts by hand at the attachment points - almost certainly a problem if you're able to move anything. Then maybe a pry bar. You should get a bit of flex from the bushings, but not very much. From what you're describing, the vehicle wanting to turn in more as the suspension compresses, can one of the links be bent changing suspension geometry the wrong way is it compresses?

 

[slow3v]

It could be.. I'm almost wondering if I'm just not used to it. All of our vehicles drive so differently, maybe I'm just not used to it, but my F-150 drives a lot better (to me). Granted, its wheelbase is substantially longer.

I'll take the Expy out this weekend sans wife + kids and huck it through some corners hard. I'll know right away if something is truly off, or if it's just me not being used to it. These awful, squishy Firestones have to go, I know that.. the sidewalls are so weak it's ridiculous. That's probably contributing a lot to what I am feeling.

I got underneath and visually inspected + tugged on everything. Sway endlinks freely, they feel nice and new and smooth, bushings look good, nothing visibly swollen or cracked, rear dampers show no signs of fluid seepage.

It hasn't been aligned in probably 4-5 years so next time it's in for service (I bounce back and forth between DIY or dealer, depending on convenience), I'm going to have it realigned.

Thanks for your help so far fellas.. if anyone else has any similar experiences, feel free to post'em.

 

[Fastcar]

Try increaseing tire pressure by 4 or 5 pounds. Just to stiffin' things up a bit and see what happens.

 

[slow3v]

Just to update, new tires greatly improved this. Threw on Continental TerrainContact's and a 4 wheel alignment (though the prev. alignment wasn't out), and she drives a lot nicer.