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Discussion Starter #1
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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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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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...
 

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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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Discussion Starter #5 (Edited)
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
 

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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.
 

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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.
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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Yes, FE5 control arms, FE5 front sway bar, Moog end links, SSC springs, later adding the Powell Hardcore rear bar.
 

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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?
 

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Discussion Starter #10 (Edited)
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,
 

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For the love of god don't get those - some members have gotten the Monroes and have gone through multiple sets. Monroe knows there is an issue and will replace them - but you'll get sick of replacing them. I think maybe the issue was more related to the struts, but still.

Just get Delcos (#560-569). Like $50 and they'll last you a nice long time.

Or 560-582 for the FE5 shocks (and they actually are a few bucks cheaper), 506-683 and 506-684 for the L/R FE5 struts, and then you'd need FE5 front/rear springs.
 

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The FE5 shocks are actually down to $45 each right now. The struts are a bit more at $85 a pop, but that's still a steal considering their quality and performance.
 

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Discussion Starter #13
Thanks all for the input. I finally found a very good mechanic who diagnosed it as multiple problems:

- Marginal front struts and definitely failed rear shocks (the KYB's)
- Failing passenger side CV halfshaft (caused major torque-steer on acceleration and deceleration)
- (90% of the problem) two bent rims. One of them because I drove on it while flat.

I had forgotten two years ago I was in a very bad part of a nearby city. I rolled over a glass bottle and the tire went flat. Rather than hanging around a bad part of town I drove 3 miles on the interstate to a police station parking lot and changed to the spare. I got the tire replaced, but the tire store didn't mention anything about a bad rim. To a layman (me) the wheel rim looked fine, but the mechanic said it was trash. Rock auto is almost giving away 15" 4-lug steel wheels so swapping it out was affordable.

The other rim had a somewhat sizeable 3/4 inch dent on the outer rim...didn't seem like a big deal but when I hammered it back into place about half of the wobbling went away (steel rims). Once I replace the passenger side axle the torque-steer should be gone (this is the M86 getrag where one axle is ~3 feet long and the other is only 1-1/2 feet long...no intermediate shaft like the MU3).

I have a question about springs: I went to multiple junkyards and they said there's no such thing as FE5 springs. One place said MAYBE the springs on the front struts are different, but they all agreed the rear springs are identical on all Cobalts. So is there a difference between springs? Or is it just stock versus aftermarket?

Thanks very much
 

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I have rear FE5, one on the right ordered directly from dealer.


And GMpartsgiant has them listed... shocks and springs...


 

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Yeah, FE5 definitely has different springs than FE1. I've had issues with junkyards just assuming things (and also being super pricey for some reason). Lots of professionals don't necessarily know the differences between trim levels of every car, Cobalts included.

If you want to get the springs from a junkyard, just ask if they've got any 2008-2010 Cobalt SS's on the lot.

---------- Post added at 08:25 AM ---------- Previous post was at 08:24 AM ----------

However, I still very much recommend the Canuck Motorsport or SSC springs. They don't slam the car, so clearance isn't an issue, they're cheap, and they provide both a good ride quality and good handling performance.
 

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Yes, FE1, FE3 and FE5 are all very different, spring and strut/shock-wise.
 

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Yeah i switched to fe5 struts and shocks. I like them personally and they are much stiffer than stock obviosly.
 

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SSC springs? Hmmm.

I need to find them
There's speculation that SSC and Canuck Motorsport are the same spring. It also seems like they're different designs, but made by the same company.

I e-mailed Canuck Motorsports and they confirmed that ZZP sold their springs, which makes it seem like SSC is made by Canuck Motorsports.

Anyway, if you want the SSC version, it's available at zzperformance.com for like $220 + shipping. If you want the Canuck Motorsport version, I ordered mine from canuckmotorsports.com for $180 shipped.
 

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So im still a bit confused still, and looking. Is that $180 for all 4 springs?
And would you say they are the same height as LNF FE5 springs?
You would choose them over LNF FE5 springs?

Right now I'm looking at 2008-2010 SS FE5 springs for my 08 LS
These are supose to be LNF FE5 springs
Frt Springs: 25833647. $41.56 each
Rr Springs: 25821162. $39.41 each just shopping on line for these 2 part numbers
As of this post, available from gmpartsheadquarters

Total $167.94 with $20.99 ground shipping
 
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