Suspension Question

[dug-mac]

I have a base model 07 XLR that I bought with 37K miles. It now has 53K and the both front shocks are leaking oil. My question to you guys is does this seem like a reasonable time at which the shocks might be worn out or does it signal hard use by the previous owner? If the front shocks are gone does this mean the rears must be on their way out, too? After all, they've had the same exposure to roads/elements as the fronts.

Thanks for your help in advance.

 

[ccclarke]

Since you're in the NE, I'd venture to guess you drive on some of the same Third-World roads I'm exposed to. I'm surprised your shocks have lasted as long as they have. If the previous owner drove the car in this area, then I'm really surprised the shocks are still functioning at 53K miles.

If you haven't done so already, check under the rear shock boots for oil residue. A little weeping is normal, but a lot isn't and could indicate they need replacement, depending on severity. As you probably already know, the MRC shocks are not cheap. If you want a newish car ride, replace all four.

CC

 

[dug-mac]

The previous owner lived in RI and I am in Mass. You really think 53K is decent longevity? Do you know the least expensive place to buy the shocks?

 

[rexster314]

cc, correct me if I'm wrong, but I read in one of the older threads here that it's possible to take the XLR to an established Corvette shop and get the adapters so you can install regular shocks instead of the high dollar stock shocks with little to no loss in ride quality. It might be something I'll look at when the time comes for me

 

[dug-mac]

So I'm finally getting around to dealing with my bad front shocks (car has been sitting inside all winter). My question is whether this job is fairly straightforward or not. I don't intend to do it myself but I don't like the local GM dealers and I know a mechanic that has worked on other cars of mine. Is there some reason that I should go to a GM dealer for this that I don't know about? Typically when they replace the shocks is it just the shock body itself that needs replacing or are there other parts as well?

Thanks for the help...

 

[rexster314]

From Chilton's DIY manual. See attachment. I have a very good local mechanic but when I take the XLR to him I usually print the corresponding "how to" for him, although he has access to the same information.

 

[dug-mac]

Thanks for that post! Much appreciated!

Doug

 

[dug-mac]

CC,

You mention to replace all 4 shocks if I want to restore it to new ride quality. I kind of thought shocks were an all or nothing proposition, meaning that they work until they fail? Are you saying that there might be a long period of reduced performance before an outright failure is observed?

Doug

 

[lextoy]

i think what he is saying is that if one is bad the others are probably close as well.
my opinion is that shocks can deteriorate over time. they dont always fail catastrophically.
it can be a slow deterioration, you only really notice once they are really bad.
but if you did replace all 4 you would realize how poor the ride was, and how much better new shocks work.
i would say if one is definitely bad, i would replace in pairs, like both rears, or both fronts.
in your case both fronts sound like they need to be done.
53 k and 9 yrs old isnt out of the norm for being worn out. its a function of use and age.
seals dry out, dirt gets in, leaks occur. hard use can accelerate the process.
i drove my benz 14 yrs on the same shocks, they didnt actually last that long
the ride got slowly worse about 5 yrs ago!! was waiting for HD bilsteins to become available in the US.

 

[lextoy]

the shock replacement looks pretty run of the mill, any mechanic can do it. probably only takes 15min per wheel, including the time to jack it up!!

 

[ccclarke]

Dug-mac,

Lextoy's explanation hit the nail on the head. When brand-new, the XLR has a very comfortable ride --in direct contrast to a similar year C6 Corvette. From your description, your front shocks sound like they're due for replacement. If your tires are in good shape, (to help evaluate the difference) and the rear shocks pass inspection, see how the car rides before deciding to replace the rears. All shocks are not created equal and will wear differently.

If you haven't already done so and the car isn't equipped, this would be a great time to upgrade your suspension and install the rear stabilizer bar, using the information provided in the appropriate thread here. It's inexpensive, simple to do and makes a world of difference in the XLR's handling.

While you're inspecting the suspension components, this might be a good time to take the opportunity and eyeball the transverse composite leaf spring adjusters and pads (which can wear and fall off.)

CC

 

[dug-mac]

Thanks lextoy and CC for the good information. I will definitely do the fronts as they are leaking. Not sure about the rears. I think they may be weeping as the shock body has some residue on it that I once thought was probably road grime but might be fluid. Next time I drive it I will look for oil under the boot. Incidentally, is this how the dealership would make a determination on the status of the shocks or is there some other test that they use? My tires might also be an issue in terms of ride quality. I have the Michelin run-flats that have about 30K on them but age might be more of the issue, being 6-8 years old. When I bought the car in 2012 with 37k on the odometer the ride was very smooth. The front shocks are definitely gone but at this point I can't tell how much the old tires are affecting ride quality.

Doug

 

[dug-mac]

CC,

I do have the rear stabilizer bar installed on my car. I had that done when it was purchased. Thanks for the advice about inspecting other components. Can you show me what specifically to look for? I'm not that good at this kind of thing.

Doug

 

[lextoy]

spring adjusters

across the front and read of the car are transverse springs. instead of coil springs like most people are familiar with.
under each transverse spring (at each end) is a large bolt with a rubber pad on the end.
this lets owners adjust the spring tension to adjust ride height ride quality etc.
usually nobody messes with these except the dealer and maybe a performance shop.
over time the rubber boot part can wear or snap off, resulting in quite a noticeable change in ride quality or stance.
example one wheel is much lower in the wheel well than the other 3... probably broken off the rubber end.
here is the thread that discusses the rubber adjusters, how to replace them, etc.
https://www.xlr-net.com/forums/cadi...lt-replacement.html?highlight=spring+adjuster

 

[lextoy]

here is a pic of the underside of a corvette. front end.
the parts look the same even though its a different car.
see the transverse spring yellow arrow.
then above each red circle , above the lower control arm, is where the leaf spring presses the rubber adjuster down against the control arm to give the suspension the spring tension.

 

[SJP]

Ok after all the talk of the advantage of the rear suspension bar, i finally ordered one. i got all the part numbers from posts, Im not sure if GM parts direct has all the parts on hand but t hey accepted order for a total of $189.04 with shipping. I generally dont drive hard, but I will give update on installation and handling results. If someone has a picture of completed installation that would be great...Thanks Steve

 

[lextoy]

this thread has really good pic.
shop can install in 15 minutes. probably charge 1/2 hr.
you can install also if you have ramps... super easy.
any one have advice on getting an alignment after the install??
since its the rear i'm not sure its really necessary.
if you havent had an alignment in 4 yrs i guess get one after you install the parts.
https://www.xlr-net.com/forums/cadi...n/2624-rear-swaybar-parts-list-04-09-a-5.html

 

[dug-mac]

Thanks lextoy for your help in answering my questions. For the record, I have the rear sway on my car and it does improve the handling overall. One final question: can you think of any other way for me to diagnose the rear shocks other than looking under the boots for moisture after driving?

 

[ccclarke]

If the rear trim height is within specs, and no oil is evident on the shock body, there are two checks that can be performed with a Tech 2 to command the shock solenoid to move and there's a voltage it can read.

CC

 

[dug-mac]

Great info CC. Can you tell me what the rear trim height should be?