New Caprice - Discussion forums

I have gone through replacing almost the entire front end trying to get rid of the shakes at 55-65 mph.
So far I have replaced the steering rack, all lower control arms, tires, brake pads and disc. I have swapped wheels as well. Had an alignment done twice.
I changed each part one at a time to test the results.
Each time a part was replaced the shake went away for around 1000 miles. But it would always come back.
My mechanic thinks the intermediate steering shaft is the culprit. Im wondering if any one has any more advice before I continue to throw money at this front end.
The even stranger part, is that the shake will go away when the front suspension is under load, as in going around a corner on the highway.
I already bought stock front struts and whiteline top strut mounts. I have no idea if these could change anything.
Btw, Its a 2013 with 80k miles.

Are your bearings snugged up? I haven't had mine apart on this car (I have a '13) but I assume you can tighten the castle nut up is not to spec.

Are your rotors okay? I changed a rotor on my Ridgeline today and fixed a shake which only occurred while braking (glazed or burned spot) but while I was putting the new rotor on, I considered how corrosion or debris between the rotor and hub could tilt the rotor(and wheel).

Also, are you running factory wheels? If not, there are many GM wheels that will fit our cars but the lug pattern is off slightly. Many report that this is fine (I ran a set that was "off" for a while and it was fine) but if you don't torque the lug nuts methodically stepping through your torque sequence, you may get one or more lug nuts "centering" in the rim hole better than others thereby making your wheel slightly off (if the center of the rim does not "center the wheel to the rim well").

Good luck. Be sure to let us know what you figure out.

I'm curious what you come up with....... I have the exact same issues and have also replaced everything....and I mean everything in the front end!! Several alignments and 2 sets of tires and still no cure. Last thing to do is a road force balance. I honestly think alot of the issue is in these steel wheels and the sheer weight and mass of them. I have heard hundreds of the same complaint from other Caprice and G8 owners about this issue. GM really dropped the ball on this design apparently. Love everything about the car otherwise.

I think a few people mentioned removing any possible rust or corrosion from the mating surface of the hub where the rotor would sit. Even if the rotor is out .005 of running true you will notice a shake. But if the shake is apparent when applying brakes and you don't have wrapped rotors or hard spots, then sometimes the only cure was turning the rotors while there still mounted on your hubs and if you remove them they need to go back exactly the same way you took them off (same lugnut holes) that worked for me. There a few good brakes shops that have that attachment.
Good luck.