I’d fixed some rattling of the trunkback on our 2002 and while it didn’t change the ride it greatly changed the perception of the ride. Less rattling equals the sensation of a smoother ride.
But reality is, it’s a very stiff rear suspension given it is what’s been called a swinging gate. Basically 3 pivot points on the chassis and the rest is welded stiff rear end structure. Newer versions use 2 bushinged arms from each side of the chassis to the straight rear axle on each side of the vehicle so all those bushings provide some give for single wheel movement.
(referring to 99-04 rear suspension design)
Study what is going on back there. The spring/shock package is one thing, but what everyone seems to be ignoring is the other elephant in the room.
Its like a gate on a hinge. The trailing arms are welded to the axle as well as the diagonal track bars. If you put jackstands on the frame, remove both shocks and you can see what I am describing. If you lift up on one wheel, the other comes up with it. There is no articulation/independence in the back axle. The only time it begins to loosen up is when the welds break. And that is exactly why it is breaking back there. The only thing this gate style suspension is good for is if you wanted to Rally race between the cones or mountain curves. The thing will make corners like a train.
Looking at the later model cars(05-13) one begins to understand why they ride nicer every year they make improvements. All connections (at the frame and on the axle) are rubber mounted and allows a little bit of flex.
For comparison, the 10 s6/el/elxd seems to have an upgraded HD version of the 09.
Let me see what else I can dig up for study purposes.
I’ll take some pictures tomorrow. My 02 is definitely different with it’s 4 rear shocks. Still swings in the same useless way but dampens differently. Also seems to have dodged the cracking because of different mounts.
I thought my 10 didn’t match the picture either, but I’ll have to look again. Now I’m not sure.
For the uninitiated, NEVA sells replacement bushings. Not expensive, like $10 each iirc. But holy schnikes… Getting the old out and new in is difficult. Even more so on the older (pre-05) ones
Suspension arms on older gems are really large and only pivot on one side so fitting them in a press is difficult at best.
10 ton press, oxy-acetylene and dry ice, still a goddamn unsafe workout. Was afraid I was going to shoot parts across the shop at 100mph the whole time.
I read somewhere about the round tubing being used on some models and speculation it was easier to bend round tubing. Odd diagram in how it shows the parts since it does not look like the chassis mounts are side-by-side but instead of over-under which would mean rotation of the axle.
Hard to believe they thought the original 2002 ‘swinging gate’ was a good way to go. As was mentioned, that thing is so stiff and ridged the rubber bushings on the chassis mounts are pretty worthless.
I’d mentioned in the other thread I ran across a version of the GEM rear suspension where the center “V” was still welded to the axle and one bushing on the chassis but the 2 straight arms were with bushings at both the chassis and the axle. The final upgrade was to have 2 arms on each side so 4 bushing mounts on the chassis.
I would like to find any info on how well that intermediate option worked. ie the one where the bushings were added to the straight arms at the axle and all else was the same.
That looks like some heavy metal support there and can’t imagine that breaking loose or cracking.
Seeing he moved the shock mounts inward some I wonder if he was looking for a little bit more clearance under the vehicle or what. This also has me wondering if changing the angle of the shock can effect the ride. As in, what would happen if the shock mounts where turned 90deg, the upper mount points fabricated to be closer together so the shocks angled inward 15-20 deg? No doubt there are a gazillion papers in the mechanical engineering books on suspension system geometry.
That looks like some heavy metal support there and can’t imagine that breaking loose or cracking.
I have seen some where the crack sometimes just moves up the arm and breaks right at the weld.
Interesting things happen when you start moving shock mounts around. As you stand the spring/shock package up (in the direction of travel), the spring rate goes up. Also the dampening becomes 1 to 1. For every inch of travel the shock also travels the same distance.
When you move one end or the other (or both?) towards the pivot, the trailing arm starts to act like a lever and you are compressing the same spring with less force but dampening is also less because there is less movement of the shock. You also start putting more stresses on the pivot bolt too.
Ya, I’ve ran across a post or two long ago in here and where they were talking about welding the rear suspension tubing. I made a check of mine and it wasn’t broken or cracking and periodically check any time I’m looking under there. And with a 2002, I’m always looking under things. LOL
Thanks for the description of things which happen when you move the shock/spring angles and it is those types of things which peek my interest in ways to deal with the fact I no longer have 4 lead batteries back there so weakening the spring and shock effect some could be useful.
I have not driven it much since having the suspension fixed as I am still tinkering with my Lithium setup…
The shocks lower mounts were kept in the stock location.
Here it is on the car
