Cadillac CTS-V - Rear end feels like its drifting out on corners. Not the tires. Any ideas??

I posted about this awhile back because i felt it on my old car and a few others claimed to experience the same thing. I honestly assumed the cut springs had something to do with it but this car has stock suspension and does the same thing.

When I'm taking corners aggressively (primarily long sweeping right hand corners), the ass end of the car feels as if it's sliding out slightly on the verge of losing control but then catches and comes back where it should be over and over again. It's a very unstable feeling. I know for a fact it's not the tires. I know it's suspension related but I don't know where to start. And I know since this is my second V and both cars have done it that others have had to experience this and hopefully know the solution.

So what can it be? Bushings or some sort? Bad strut? Sway bar?

Any help will be appreciated. The car runs and drives fine other than this. Slow corners... No issue. It's the longer sweeping corners that I noticed the lack of stability in the rear end.

motor mounts

I've never had this issue and never heard of anyone having it.

The only possible physical explanation I can come up with (other than suggesting that you're jerking the car around or that there's a gentle undulation) is that the mass/damper system formed by your springs and shocks is very nearly unstable under the lateral loading you're throwing at it.

Changing your spring rate, dampening rate, or lowering your car's center of gravity should solve the problem.

wow fuzzy that response gave me a sex boner

No kidding lol... I was thinking maybe the rubber bushings and mounts being overworked

Does it happen in both directions?

Alignment is big... The floating cradle doesn't help. Trailing arm bushings are weak.

Motor mounts suggestion may have merit. I was surprised to see how much a firmer cradle subdued the shutdown shimmy.

You might have a 'loose' bolt too. I found my cradle bolts much looser than the recommended torque when I first removed them. Some have discovered loose trailing arm and control arm bolts in the past.

But NS002 says this is a repetitive thing. Low frequency.

His description is uncharacteristic of busted motor mounts.

wow fuzzy that response gave me a sex boner

Or busted anything...else. Giggity.

Its definitely not the motor mounts. I just swapped those not too long ago with UMI solids so those are good.

I really haven't noticed it much on left turns... primarily right turns where the ass would naturally push to the drivers side. Its definitely repetitive and its gotten worse it seems like. Feels like the tire rolling under and coming back... like a dip feeling. Any sweeping turn even at moderate speed i feel the ass shift like i described. Its weird but its def more prominent on right hand turns like i said. On my old car, I'd even feel is when I'd change lanes over the bumps. It was like a wishy washy feeling back and forth in the rear end.

Ill have to check for loose bolts next time im under the car. When i had my exhaust done not too long ago, i took a look and didnt see anything loose or out of place visually but maybe i need to check them all with a torque wrench.

My old car did this and now this one. I wasnt going to worry about it since i plan to install the map arms and drop springs (either H&R's or GC) very soon but figured id post up and see if someone else experienced this same feeling and knew a solution off the top of their head. I was thinking maybe bad bushings of some sort or maybe a bad drivers rear shock. I really would think so though because it drives and handles fine other than in this particular cornering instance.

If you had something loose, I'd expect that you'd hear a click / clunk / clatter.

Me too. But it never makes any noise which is why I have no clue where to start on it...

Check the motor mounts dude www.cadillacforums.com/only-thing-wrong-with-CTS-V-is-motor-mounts-spun-rod-bearing-check-motor-mounts.html

Im going to check those anyway since its been a couple thousand miles just to ensure its all nice and tight but im sure thats not the issue in the rear... lol

I'll give the same response I gave last time - alignment (http://ls1tech.com/forums/16198231-post6.html). Have you gotten it aligned in the past few months? And if so, what are the numbers?

I haven't gotten it aligned. Its stock height and drives straight. On my old car it might have been a possibility because it was lowered and was never aligned. This car is all factory suspension wise.

I'd like to see the numbers on an alignment too. My car would do something similar to that, but it went away with alignment. My rear was toed out slightly though.

Fill your cradle bushings with polyurathane. It will fix your problem. ;-)

Im a cadillac tech, let me tell you alignment on you v-is not easy to set up
correctly so make them give you a print out were it shows you a before and after any good shop will give you this print out, also the cradle bushing can also give you this condition but start with alignment.

Another thing to consider is that these cars are very rigid... It's insane to see it up on three jack stands and perfectly level. So, there will be very little give under stress... the weak rubber bushings will stretch first. I get the same strange feeling when I take hard turns or my car catches a rut in the road... feels like the rear end wants to go a separate direction. It certainly can be the alignment as per the Caddy tech, but I'm betting it's the rubber cradle bushings, control arm bushings, trailing arm bushings, etc... especially if you have a wider tire in back

I haven't gotten it aligned. Its stock height and drives straight. On my old car it might have been a possibility because it was lowered and was never aligned. This car is all factory suspension wise.
Stock suspension and drives straight doesn't mean your alignment isn't off, as I also told you in the last thread (http://ls1tech.com/forums/16218019-post16.html).

I'm 95% sure it's in the alignment or 5% it's something loose. I had the same thing happen when my alignment was done the toe was just a hair off. When I went over 75 and would change lanes it would wiggle real bad and on a long sweeping turn it would feel like it was coming out from underneath me.

I nearly ate the median on I45 driving through conroe, and all that construction when I decided to pass a big rig, and it started to come out from underneath me. I hadn't been that scared in a long time :eek2:

Another thing to consider is that these cars are very rigid... It's insane to see it up on three jack stands and perfectly level. So, there will be very little give under stress... the weak rubber bushings will stretch first. I get the same strange feeling when I take hard turns or my car catches a rut in the road... feels like the rear end wants to go a separate direction. It certainly can be the alignment as per the Caddy tech, but I'm betting it's the rubber cradle bushings, control arm bushings, trailing arm bushings, etc... especially if you have a wider tire in back

My thoughts exactly. I would definitely think one of those would be the culprit.

I'm 95% sure it's in the alignment or 5% it's something loose. I had the same thing happen when my alignment was done the toe was just a hair off. When I went over 75 and would change lanes it would wiggle real bad and on a long sweeping turn it would feel like it was coming out from underneath me.

I nearly ate the median on I45 driving through conroe, and all that construction when I decided to pass a big rig, and it started to come out from underneath me. I hadn't been that scared in a long time :eek2:

Sounds like the exact feeling i get. Well... If its alignment related, ill wait until i install the ground control kit before i go spend money to align it. No sense aligning it twice.

UPDATE***

While installing my brakemotive rotors and pads last night, I discovered the likely culprit to my problem. The tie rod bolt near the rotor on the drivers rear wasn't even hand tight. I torqued it down nice and snug and it seems to have cured that feeling so far. Glad I caught it when I did!!