I have a 2008 C6 with Mag Ride Control (F55) with 89K miles on it and the rear end has essentially collapsed. It started with the left rear sitting really low so I looked under and saw the shock was leaking. I looked at the right side and it too was leaking. I thought it best to just replace both of them, both from a maintenance standpoint and for equal handling and ride quality. Well, by the end of the week, the right side fell. I ordered the shocks and just finished installing them. When I lowered the car back down, it looked perfect. I took it on the test drive around the block and it felt horrible. It was harsh and choppy. Once I got back home and looked at it, both sides were just barely off the tire again.

Looking through the suspension with the car raised, it looks like the leaf spring was touching the diff housing, but I'm thinking this is because of the upward bow caused by lifting both wheels in the air. Once it's on the ground, it's hard to see it, but it looks fine. I couldn't find any obvious cracks or breaks in the leaf, but there's gotta be something that's not allowing the car's weight to be supported.

Any ideas on what to check out next? I'm new to this forum, so I'm guessing I can't post pics until I reach a certain number of posts. I'll attach the pics of the ride height when I can. Thanks in advance.

 

no idea what's wrong. sounds likes springs are wrong somehow. do you use wheel cleaner? I'm no help but others will chime in.

pics are free; just get a host free place like photobucket, post them on there, then hit copy of each pic and put it in your thread.

 

Yeah, you can post pics BUT you have to do it from an internet hosting site like Flickr, Tinypic, photobucket, etc.

Here's the old and new Tutorials for photobucket from our Help Forum:

http://forums.corvetteforum.com/help...es-thread.html

http://forums.corvetteforum.com/c1-a...irections.html


As for your problem, it almost has to be a broken spring as that is what supports the weight of the car.

Here is just one example, does yours look like this?

http://forums.corvetteforum.com/c6-t...ing-today.html

 

Thanks for the help on the pic posting. I'll see what I can do.

Yes, mine looks just like that now. I saw that post while searching, but I can't find any cracks anywhere. I did notice I have a leak from the rear diff and the center of the spring has this fluid residue on the center section. Perhaps this has somehow broken down the fiberglass resin/composite of the leaf spring??? Sounds like a reach, but maybe it's possible.

As you said, it has to be the spring... I can't think of anything else that would support the weight. I was able to get the numbers from the spring: left side is stamped EP-GF72 and the right side is stamped 22208992. I tried to search briefly but couldn't find anything with either of those numbers. I'll look more and see what I come up with.

 

Yeah, chemicals/fluids can do that. Some have damaged them by running exhaust cutouts and aiming them right at the spring.

 

Here is the album in photobucket:

http://s483.photobucket.com/user/cpa...e%20Suspension

hopefully that works

 

Current collapsed status:





Normal:





Differential leak above spring:

 

Perfect, thank you!

 

So, if it's the spring, now the question is do I replace it with like kind, or look to go with Z51 or Z06? If went with something other than stock, I would do both front and rear along with swaybars. I don't really track the car but do like to have fun every now and then. Mostly a daily driver. Been happy with ride and performance of F55, but wouldn't mind slightly stiffer if it meant more stability when pushing the car a little.

 

Well, just FYI, the non-Z51 rear spring rate that you have now is 12 pounds stiffer than the Z51 rear spring, 657 vs 645. Just sayin'.

But you would probably want to go the full Z51 spec if changing.

 

Interesting... Man, you're better than Google! In all seriousness, thank you Rick. I really do appreciate the help. Honestly, I really do enjoy what I have now, but upgrade fever always sets in pretty quickly and the mind gets going. I'm thinking I'll just get the direct replacement and just keep driving it.

 

Let me know if you need a leaf spring. I just removed my base ones today (40k) and would sell you one cheap if you need one.

 

Can you tell me more about it - Base C6, F55, Z51?

 

Instead of replacing the leaf spring... Consider a coil over package from forum vendors for around $1600 to $2k. That is a real upgrade and probably not much more than your two magnetic shocks and a new spring.

 

I considered that, however trying to resale or trade a car with Mag ride control without the mag ride control doesn't fare so well. If I would've had this problem early on, I would've converted.

I've already replaced the two rear shocks so I'm already committed to keeping the F55 system. It actually does its job quite nicely for a non-track car. It doesn't feel like a go-gart and you can dial in stiffness when you want it. And I didn't pay dealership costs for the replacement shocks, not even half that.

If I were building a play car with track time, I'd go coil overs, but for my daily driver, though quite spirited, I'm the limiting factor for performance, not the system.

Another thought: I know many have done what you are recommending, but the shock mounts weren't designed for the load of bearing the weight of the vehicle, much less the shock load of a coil over.

With the homework I've done, it seems my real troubles have stemmed from the diff leak and not the suspension system. Unless you consider the vulnerability of the leaf spring to be a fault. Which I actually do think sucks. But then again that's because I actually have to fix mine.

Thanks for the thoughts though; I've been everywhere on this trying to figure out what I want to do with it.

 

Base C6 which I think is the same as F55. 2005 with 40k

 

Not to steal the OPs thread, but I think Im facing a similar issue. Please see the photos below. Heard a "pop" sound when exiting the driveway last Friday. Thought a shock blew, but its not giving the old Cadillac style bounce that would go with blown shock(s) when you press on the rear quarters. Unfortunately the car is so low in the rear now, I cannot get my jack underneath the car from any angle. Car has 112,000 on it. Mildly modded (engine/exhaust). Still on the stock shocks (06 Base Model Non-Z51).

Thoughts? No Diff leak and No Cutouts.

Driver side


Passenger side:



Driver side w/ tape measure (26" to fender)


Passenger side w/ tapemeasure (26.5" to fender)

 

Well, yeah, probably. Drive up on some boards so you can get the jack under it. That's all you can do, you have to inspect it to diagnose it. Springs do fail, not often, but they do. Please let us know.

 

Regarding the OP's problem, the differential fluid is basically a high quality oil, with some additives. I would be slightly surprised if the oil would cause his spring to fail.

But I've been wrong before, just ask my wife...

 

Ask us too.