Figured I might as well post some pics of this process and talk about it some. This is the fourth time I will have gutted this car's underside, so I feel fairly comfortable with this procedure now. I know a lot of folks would be impressed to see just how straightforward this is, so maybe it will be a "gee-whiz" for some of CF. If not, well, picture write ups are always good for reference. On with it...


First, take one C6:



Then, elevate it with a pair of floor jacks, and a quartet of jack stands. Remove the rear wheels.



Now gather up your tools. In my case, simple hand tools. No baller stuff here. You can use what you like. I'm a po' man.



Enlist the aid of a helper... preferably one who can differentiate between metric and standard:



And your helper's helper:



Ensure they have a solid grasp on the plan, not your gloves... (You're not helping, Egore!):



And that they understand the concept of personal space:



Now that's better. Good Egor, good. Sit.



...more to come, shortly.

 

Now, here's what we're working with:



And here's the rear suspension, which has to be partially disconnected. We're going to remove the upper A-arm bolts at the frame, as well as the upper coilover bolts, which will allow the suspension to separate from the car. (I understand most of you won't have coilovers. Substitute that step for unbolting your shocks, and the leaf springs will be self-explanitory, as they're just held in by a pair of brackets at the bottom of the spring).

The lower A-arms will stay bolted to the suspension cradle (the large, aluminum, square apparatus that holds them [and the diff] in place). When we do this, we will also have to disconnect the parking brake cables, the ABS sensors, and remove the brake calipers from the caliper brackets. The calipers will be secured up and out of the way, with brake lines never needing to be disconnected, preventing extra work. This of course needs to be accomplished at both sides of the vehicle. Be sure to follow each harness up and around the cradle, as there are multiple attachment points to the cradle itself to secure them all. They're often little ribbed pegs that need popped out kind of like interior panels. If you have an F55 car, now is the time to disconnect the ride sensors and associated pigtails.




Alright, now that we looked at how we're going to disconnect the suspension, lets look at what mounts that entire rear suspension cradle in place. About dead center in this first picture, and upper left center in the second picture, is a vertical nut/bolt that fastens the cradle to the frame rail. There are four of these; two at the back of the cradle (first pic) and two more at the front of the cradle (second pic). These need to be loosened, but not removed just yet.






However, before we can drop the cradle, we need to make sure it's not still attached to the differential, which it serves as the support for. Notice in this photo near the upper left of the pic the two nut/bolts protruding downward, and the other similar two off in the background near the bottom of the pic. These four bolts are what secure the differential to the cradle.



...next post coming up in a moment.

 

Since we're under here at the moment, lets take a look ahead and see how the differential attaches to the transmission, and where the transmission attaches to the torque tube. The torque tube is something unique to rear-mount transmissions. It has a "bellhousing" at the front of it which contains the clutch and flywheel, then necks down into a long, one-piece steel tube which contains the driveshaft. At the back of the torque tube is another "bellhousing" facing the opposite direction that bolts up to the transmission. The input shaft of the transmission splines up and slides into the torque tube, and subsequently the female end of the driveshaft therein. First pic will be some of the lower bolts that mount the diff to the tranny, second is a couple of the upper points.





In this picture, at the left, we can see a few of the bolts that secure the transmission to the rear of the torque tube.



Next post soon.

 

Alright, picking up where we left off! Now that we've gone over everything to this point and taken a look at what all needs to be done, we've got our plan thus far, so lets turn some wrenches.

Now, we just dismount the upper a-arms and top end of the shock (or coilover in my case) from the vehicle- two simple bolts for the a-arm, two small ones for the shock:





...we need to get up under there and pull the axles from the differential. These will be staying attached at the hubs for ease of operation. To do this, since now the hubs and suspension can swing down and help tug on the axles, the upper axle cups can slide out from the diff. All it takes is getting up in there with a pry bar and popping them out with a little elbow grease. This is looking directly upward:



And once you do, presto! They slip right out! No clips! PS: Those empty bolt bosses are where the leaf spring straps used to be.



At this point, we can prepare for the dropping of the cradle by ensuring we get a bottle jack under the transmission and differential assembly, and getting it supported nice and snug. Once you've got it stable, completely remove the four nuts that secure the diff to the cradle, leaving the studs hanging. This is pictured in the photo below. They're attached to the urethane diff mounts on the diff itself. The cradle will slide down off of them once the cradle is loose. Your jack positioning will look like this (wrench for reference as to necessary jack size):



Next step is to get your two hydraulic floor jacks underneath the cradle itself and make sure you've got it nice and supported at both sides. It's a large chunk, it's heavy, and it's weighted in an awkward manner. Two jacks are best, trust me. I'm sure it can be done with one, but I wouldn't try it without a helper. While I did enlist a pair of them, neither of my helpers have opposable thumbs. So much for that.



Now with the cradle supported, we can begin loosening the four major bolts that mount the cradle to the frame. In this next photo, ignore the coilover in the center of the pic and focus on the left and right edges of it. At each, you'll see the fore and aft bolts/nuts that we've begun to loosen. Obviously, repeat for the other side.



Once all four bolts are off, you can now begin slowly and carefully lowering the cradle away from the frame. Be sure to stop after a couple inches of travel and check for any obstructions that may be in the way, such as harnesses, brake lines, wires, loom, cables, whathaveyou. If they're caught on or under, or are still attached to the diff/cradle, they will be ripped from the car. USE CAUTION and GO SLOW. Now go ahead and continue lowering the assembly, one jack at a time, left/right, left/right, until it's clear.



Once you've got it down and away, simply roll the jacks back out from behind the car and admire your naked suspension, and better yet, your handywork!



This is what you'll be left with up to this point.



...that's it for now. Shortly we'll be removing the differential and transmission, all harnesses and sensors, bolts, fasteners, and shift linkage, etc. Stay tuned.

 

Wow, outstanding write up. Why are you doing it?

 

I've done this several time for myself and friends, and it still amazes me how easy it is
But I've never taken pictures, Kudos for a nice written thread.

 

Thanks, Gents.

Les, this particular time it's for a blown clutch slave cylinder. The new one showed up this morning on a big brown truck, so after this here sandwich break, I'm pushing through into the afternoon to see how much I can knock out. I'm not a fast-mover though. I often lose motivation for a bit and just lay on my back staring at the undercarriage awhile .

 

So, I'm on the edge of my seat.....get the rest of the story posted before I fall off please. And I have to know what happens to Egor in the end.

 

i am getting ready to do this exact thing! hoping to swap in a new fuel pump while im in there.

 

Perfect time to do it

 

It's ashame it's such a big job for such a simple item.

 

Very cool!

 

Which pump are you going to put in. I just got an email form Brian at Hinson Super Cars and he says he has the new high flow Aeromotive 34xs
in and they are working on which one will be best for the C5 and C6.

BJK

 

Great write up. I just finished up doing the coiler conversion myself so I can identify with what you are taking about and the pictures make it real easy to be confident if I need to go further in the future.

BJK

 

Great write up!!! Thanks for taking the time. Funny too!

Since you went with coil overs, you must appreciate fine handling. I can report that when I went from base sway bars to z06 bars on my c5 it was a Great mod. I think it would be for you as well. Really tightened up the cars's handling.

P.s. Phil I didn't know you did these.......and you think they are easy! I'll remember that!

 

That made me literally laugh out loud. To the point my wife and the friends she has over stopped talking to ask me if I was OK.

My buddy and I call this a "safety inspection"

 

It says "central Coast" in your profile- where are you located? I wouldn't mind seeing this in person as I'm going to be doing the same sometime. You work at Vendenberg?

 

You made someone with a lift envy you. Kinda hard to daydream off when you have to stand.

 

Nice write up. Looks "fun" but I don't want to be doing all that. I do love the coilovers and would like to buy some and install them in the future. I'll have my car up on the stands in the next few weekends to install my headers. I can't wait.

 

I'm enjoyin this thread! Thanks for takin the time to post it.