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post #1 of 20 (permalink) Old 05-03-2016, 06:12 PM Thread Starter
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Rear End Really High Up? Spinning Out, '07 LS Coupe

Hi,

I was wondering if someone could help with this problem. My '07 LS coupe (FE1) at 86,000 miles is a great car body and drivetrain-wise (very low rust, reliable start, getrag 5-speed), easy to work on, but the past few years I've had some very serious wobbling at highway speeds.

In troubleshooting I've found what I believe were compromised parts that could've resulted in catastrophic failure, but I've still got the wobble. I live in the salt belt and some of these items failed due to rust. Some of the items I've replaced in the past three years are:

- shocks and struts with KYB's at ~50,000 miles (~4 years ago). The rear stock shocks were dripping oil from salt-belt rust holes
- rotors and pads ~3 years ago due to warping. No problems since.

Last year I went nuts replacing parts, and it helped the car a lot with other problems, including :

- entire rack & pinion & all tie rods (was clunking when moving the tire by hand at 9 & 3 o'clock...new parts eliminated the clunk)
- front lower control arm, moog problem solvers (fixed the low-speed bushing clunk)
- KYB upper strut mounts (one OEM mount had torn completely off the rubber, the other looked ready to fail).
- FOUR new tires professionally installed and balanced (old tires were almost 8 years old). New ones are a Michelin brand I think
- stabilizer links
- calipers and hydraulic hoses (was bleeding brakes and the bleeder on both OEM calipers broke flush with the caliper)
- greased and torqued everything (moog stuff has zerks)
- two alignments

This year I replaced the intermediate steering shaft (u-joint had rusted and seized; the car wanted to keep turning after making turns) and also the front bearing and hub assemblies.

After all this I've still got extremely bad high-speed wobble. The car occasionally feels like it's a boat, floating on water sideways and ready to flip sideways especially in strong winds. I can barely get up to 55mph meaning EVERYTHING passes me on the highway.

However, the wobbling has gotten worse. Last November I spun out going up a steep hill / blind-curve in the rain; the rear end wanted to keep going straight, so the back-end of the car swung around and I couldn't believe the car was spinning out. I was only going 25-30mph up the hill. Luckily I only ended up in a ditch and got pulled out.

Looking at the car the rear end seems very high. I did the "bounce test" and it bounces twice. I also put about 400 lbs of items in the back seat and the rear end lowered dramatically. The bounce test on the front barely moves, no bouncing at all.

These KYB excel-G rear shocks barely have 30,000 miles on them and they look like they're covered in oil and road dirt. Has anyone else had KYB's fail on them this quickly? Anyone have success with submitting a claim for the lifetime warranty?

Thanks,
Dan
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post #2 of 20 (permalink) Old 05-04-2016, 04:04 AM
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I resolved this issue with my 2010 by replacing the rear springs and shocks with OEM ACDelco FE5. But it is a lot stiffer and the ride in the city is not as comfortable, very pleasant now at highway speed.

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post #3 of 20 (permalink) Old 05-04-2016, 04:55 AM
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Do you have an image of how the car sits on level ground? The ass on these is usually a touch higher, but I never had any stability issues like this in my Cobalt (or my wifes Cobalt when she had it) when it had stock suspension - and I had it well past the stock limit 110...

1986 Chevrolet Camaro IROC-Z - Wrecked/Sold
1998 Chevrolet Cavalier - Wrecked/Donated
2007 Chevrolet Cobalt LT - M62 Supercharger, Ported Throttle Body, 42 lb/hr Injectors, Intense 2.9" Pulley, Cobra Heat Exchanger, SS/TC Exhaust, TTR Engine and Trans Mounts, Trifecta Tune, ZZP Header and Downpipe, '08+ FE5 Struts/Shocks, SSC Springs, FE5 Control Arms, SS/SC Front Swaybar, Powell Hardcore Rear Swaybar, 18" MSR 045s, Dunlop ZIIs, Nightshaded Tails/Side Markers, Shorty Antenna, Black Bowties, Black Grilles, Black Headlights, Dual JL 12" w1v2 Subs, A/D/S Front/Rear Speakers, G85 Recaros, Leather Rear Seats, 160 MPH Cluster.
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post #4 of 20 (permalink) Old 05-04-2016, 06:47 AM
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Quote:
Originally Posted by WillBeck View Post
KYB
KYB makes aftermarket stock replacements, don't bother.
Now, that's in the "Performance Suspension FAQ/Advice" thread, so maybe it's referring to how they're not an upgrade over stock FE1 shocks/struts, but I took it to mean they're not good quality. Maybe they're blown out already? If so, you can pick up the FE5 struts and shocks and either FE5 springs or some cheap lowering springs to replace them. If you go that route, then make sure you don't use FE1 springs with FE5 struts and shocks. I'd recommend Canuck Motorsport springs because they're very affordable and still give a fairly comfortable ride.

Driver Side Strut
Passenger Side Strut
Shocks
Canuck Motorsport Springs


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Believe me, these cars have a habit of growing on their owners. Your feelings will only strengthen over time...
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post #5 of 20 (permalink) Old 05-04-2016, 10:54 AM Thread Starter
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Thanks for all the replies. I think going the FE5 route on struts/shocks/springs is a good idea, I'm just worried it might interfere with other parts. I don't mind a stiffer ride if it means the car stays straight and doesn't float and wobble. The car was awesome when new, I'd like to get it back to that condition.

I'll try to get before and after pics of the car with ~400 lbs in the backseat/trunk and then empty again, plus measure the difference in rear height changes.

Last month I had someone test-drive the car (on local roads) and he said the car felt great, and I admit the car runs great on local roads and low-speed highway (construction areas, etc.); it's when things open up and people start doing 65 mph in the slow lane that I get into trouble, especially on pothole-patched overpasses and strong winds. Getting 42mpg on the highway is nice, but it's not worth the stress wondering if I'm gonna end up flipping or rear-ended.

I'm thinking about it a little more, and I wanted to add the wobbling started about 8-10 months after replacing the shocks and struts (looked up the records, struts/shocks replaced July 2013, minor wobbling started around April 2014). The car was awesome for those months, it got bad so quickly I never thought it would be the KYB's that failed. I didn't use vice-grips on the struts, and I *definitely* didn't abuse the shocks; they're just two bolts torqued to spec (81 ft-lb lower 66 ft-lb upper).

When replacing the struts I cleaned and heavily greased the stock front-strut tower bearings and re-used them, but I got a slight ticking when turning out of parking lots. I didn't get quick-struts at the time; I don't mind using manual spring compressors, but I think next time I'm just gonna get quick-struts...that way I get all new parts included. Replacing one strut-part at a time is a waste.

Dan

Last edited by gbreadman; 05-04-2016 at 11:19 AM.
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post #6 of 20 (permalink) Old 05-04-2016, 11:02 AM
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FE5 parts won't interfere with anything. It's the go-to swap because of it's excellent results and low all-around price. I've been on FE5 shocks/struts since the summer of 09.

1986 Chevrolet Camaro IROC-Z - Wrecked/Sold
1998 Chevrolet Cavalier - Wrecked/Donated
2007 Chevrolet Cobalt LT - M62 Supercharger, Ported Throttle Body, 42 lb/hr Injectors, Intense 2.9" Pulley, Cobra Heat Exchanger, SS/TC Exhaust, TTR Engine and Trans Mounts, Trifecta Tune, ZZP Header and Downpipe, '08+ FE5 Struts/Shocks, SSC Springs, FE5 Control Arms, SS/SC Front Swaybar, Powell Hardcore Rear Swaybar, 18" MSR 045s, Dunlop ZIIs, Nightshaded Tails/Side Markers, Shorty Antenna, Black Bowties, Black Grilles, Black Headlights, Dual JL 12" w1v2 Subs, A/D/S Front/Rear Speakers, G85 Recaros, Leather Rear Seats, 160 MPH Cluster.
2014 Chevrolet Cruze Diesel - 17" MSR 013s
1981 Chevrolet Camaro Z28 - JVC Ribbon Tweeters, SEAS Mids, Pyle Woofers, Kenwood Tape Deck, Zapco Amp/Equilizer, Ceramic-Coated Longtubes
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post #7 of 20 (permalink) Old 05-04-2016, 11:15 AM
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Quote:
Originally Posted by MP81 View Post
FE5 parts won't interfere with anything. It's the go-to swap because of it's excellent results and low all-around price. I've been on FE5 shocks/struts since the summer of 09.
Well, you also went ahead and did FE5 control arms and maybe some other stuff if I remember right.

I did just the FE5 struts, shocks, and CM springs, nothing else, and no complaints here. I'd wager that it's the perfect trade-off between price and performance. Plus, it's nice that it bolts in with no modification, and doesn't negatively affect anything.


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Believe me, these cars have a habit of growing on their owners. Your feelings will only strengthen over time...
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post #8 of 20 (permalink) Old 05-04-2016, 11:21 AM
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Yes, FE5 control arms, FE5 front sway bar, Moog end links, SSC springs, later adding the Powell Hardcore rear bar.

1986 Chevrolet Camaro IROC-Z - Wrecked/Sold
1998 Chevrolet Cavalier - Wrecked/Donated
2007 Chevrolet Cobalt LT - M62 Supercharger, Ported Throttle Body, 42 lb/hr Injectors, Intense 2.9" Pulley, Cobra Heat Exchanger, SS/TC Exhaust, TTR Engine and Trans Mounts, Trifecta Tune, ZZP Header and Downpipe, '08+ FE5 Struts/Shocks, SSC Springs, FE5 Control Arms, SS/SC Front Swaybar, Powell Hardcore Rear Swaybar, 18" MSR 045s, Dunlop ZIIs, Nightshaded Tails/Side Markers, Shorty Antenna, Black Bowties, Black Grilles, Black Headlights, Dual JL 12" w1v2 Subs, A/D/S Front/Rear Speakers, G85 Recaros, Leather Rear Seats, 160 MPH Cluster.
2014 Chevrolet Cruze Diesel - 17" MSR 013s
1981 Chevrolet Camaro Z28 - JVC Ribbon Tweeters, SEAS Mids, Pyle Woofers, Kenwood Tape Deck, Zapco Amp/Equilizer, Ceramic-Coated Longtubes
2017 Chevrolet Volt LT - New DD
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post #9 of 20 (permalink) Old 05-04-2016, 11:23 AM
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I've been thinking about switching to the Moog end links, but my current ones don't have any problems so far. Think it'd be worth it?


Quote:
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Believe me, these cars have a habit of growing on their owners. Your feelings will only strengthen over time...
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post #10 of 20 (permalink) Old 05-10-2016, 08:46 AM Thread Starter
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Hi again,

I got pics of before and after. I also took the KYB's off the car. They were in horrible condition. One refused to expand and didn't have oil anywhere, so it must've dried up and failed long ago. The photo was taken 12 hours after removal and pushing in the piston; no movement in all that time.

The other shock was still functioning (barely) and leaking badly, corroded near the piston base. These shocks are less than 3 years old and the problems started less than a year after purchase. I believe Parthros is correct in saying, "Not good quality".

With 250 lbs loaded in the back:


Empty just before removing shocks:


The KYB shocks:


Rock Auto said a return is "authorized" then double-spoke and said they don't accept returns after 1 year but the manuf. warranty is still valid so they said go through the manufacturer...but the manufacturer says go through the retailer. Typical "lifetime warranty" car-part B.S. runaround. I'm gonna ship them direct to KYB regardless and I'll let you know either way if they honor the warranty or not.

The bounce-test did nothing...with the failed shocks the car bounced twice, after removing the shocks the car bounces 10 or 11 times. It was funny seeing the car bounce like a 30 year old lincoln continental.

For now I'm gonna get Monroes, I can't afford anything more after all this failing junk. I accept they'll only last two years tops and I'm going to junkyards for other stuff so I'll look for the FE5 springs. Finding intact REAR stuff on Cobalts is easy...I've seen a half dozen cobalts and the front end is always crushed. These cars are dying violent deaths.

Thanks again,

Last edited by gbreadman; 05-10-2016 at 08:51 AM.
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