914Driver
914Driver MegaDork
8/23/19 3:27 p.m.

2009 Jetta with progressive springs, lowered 2".  Tires are 245-45-17.   This is a new phenomenon; when you hit any kind of bump in the road, the back end of the car bounces off to the right.  Not much, but not normal.  Hitting a curved exit ramp at speed, accelerating to match traffic, any tarmac burble is work.

The suspension was done 100,000 miles ago, so it's not that.  Nothing shakes, rattles or clangs when up in the air.  (my Saab 900 made noise every 5,000 miles when the shock bushings went south) .  The wheels  don't shimmy or shake in the air.

Again, this is a new thing, not a horrible thing, just new.  It jumps to the right also hitting a bump in a straight line at 45-ish MPH.  Alignment is according to Hoyle.

Thanks, Dan

NOHOME
NOHOME MegaDork
8/23/19 3:47 p.m.

Bad rear suspension link bushing.

jimbbski
jimbbski SuperDork
8/23/19 3:58 p.m.

I would have to agree. Something is worn or loose.  Sometimes something doesn't have to squeek or rattle to be worn out.

Ransom
Ransom UltimaDork
8/23/19 4:03 p.m.
914Driver said:

The suspension was done 100,000 miles ago, so it's not that.

I know that's short for the expected lifetime of a well-treated bunch of suspension bits, but still, you're killing me...

Dr. Hess
Dr. Hess MegaDork
8/23/19 4:29 p.m.
Ransom said:
914Driver said:

The suspension was done 100,000 miles ago, so it's not that.

I know that's short for the expected lifetime of a well-treated bunch of suspension bits, but still, you're killing me...

He did clearly say it was a Funny suspension issue.

Knurled.
Knurled. MegaDork
8/23/19 5:41 p.m.

Zero your toe-in and check your dampers.

 

Volvo S60/R/V70Rs are known for/bad for doing this, people call it "side hop".  Volvo lowered them from the factory, and it puts the rear suspension into a region where the toe change in suspension travel really ramps up.  Zeroing the toe helps, as does installing a stiffer rear stabilizer bar (reduces relative change in ride height)

 

You shoulda seen my '89 Golf when it blew a rear shock.  Because of the high amount of toe in VW engineered into the rear beam, you'd hit a bump with that wheel and the back of the car would want to se what was going on in the next lane.  Right shock died, so that wheel would lose traction (tires don't grip when they are bouncing) and the left rear would shove the tail end over.

914Driver
914Driver MegaDork
8/23/19 6:12 p.m.
Dr. Hess said:
Ransom said:
914Driver said:

The suspension was done 100,000 miles ago, so it's not that.

I know that's short for the expected lifetime of a well-treated bunch of suspension bits, but still, you're killing me...

He did clearly say it was a Funny suspension issue.

Oh come on, I can’t know EVERYTHING.

Thanks for the advise, will have it looked at.

 

Dan

iceracer
iceracer UltimaDork
8/23/19 6:32 p.m.

Sounds like it could be a bad shock.   Car bounces ?

Streetwiseguy
Streetwiseguy MegaDork
8/23/19 7:51 p.m.

I once drove an XC90 with one dead rear shock.  Scared the poo out.

Appleseed
Appleseed MegaDork
8/23/19 10:38 p.m.

Funny how? 

It it a clown? 

Does it amuse you? 

jimbbski
jimbbski SuperDork
8/24/19 8:17 a.m.

Now that some have mentioned a bad shock for the cause I can attest to the fact that one bad one can cause this. My friend's Ford Focus wagon did that for a while and I kept telling him to get it fixed.  Finally we went and ordered all new shocks and struts and problem fixed!

Curtis
Curtis UltimaDork
8/24/19 9:51 a.m.

I have a similar issue on my [insert any piece of junk car I have ever owned]

Right now on my truck, the front alignment is off and it pulls right.  That plus a little bit of slop in the steering box means I have the same thing going on.  When I go down the highway, I'm every so slightly holding a tiny bit of left pressure on the wheel.  Hitting a big bump allows the front tires to turn a fraction of an inch against that pressure.  The result is a bit of rotation on big bumps.

It is also possible your lowering setup as put you into bump steer.  Unlikely since things are pretty symmetrical on those cars, but something to consider.

Also ^^^ what they said.  Bushing.

GameboyRMH
GameboyRMH MegaDork
8/24/19 9:55 a.m.
NOHOME said:

Bad rear suspension link bushing.

Was thinking the same thing, although this should show as one corner of the suspension being more "flexible" on a lift.

Vigo
Vigo MegaDork
8/24/19 2:36 p.m.

I just want to point out that when you say "I just replaced that!" and it turns out it was 100,000 miles ago, a mechanic has to work hard to keep a straight face. Sounds like a rear control arm bushing to me. 

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