bushing lifespan on the shelf
 

Does anyone have any idea or experience with what is an acceptable amount of age for a NOS bushing part sitting around? If I purchase a control arm for example, with the bushings already installed and it's been 5 years, I imagine it's probably ok. Much more than that, who knows.

Genuine MBZ properly stored should be fine for 10 + years. Most last 20 years in reasonable/normal use conditions.

Through the years I've learned two things that have a major impact on bushings:
1.) Their original quality, and
2.) Not being tightened until they are in their normal use position.

Tightening the bushings and then putting them into position with weight causes torsion that will eat the bushings in short order.

Good luck!!!

Just curious, how would they get tightened outside of their normal-use position? I figure in the act of pressing them in, there will be stages of uneven compression until it's sucked in entirely.

The constant torsion on the bushings occurs when parts e.g., control arms are tightened in place without the weight of the car on the wheels.

Do you mean for instance, the final tightening of the eccentric hardware on the front LCA? Otherwise, it seems like standard procedure to get the bushings and end caps flush on the part before final installation. Likewise with trailing arm bushings, getting them fitted evenly and test-fitting to the subframe before final installation on the car.

Bushing bolts/nuts should NOT be torqued to spec until the car is sitting on the ground at normal ride height. With suspension jounce/rebound motion the bushings are strained in torsion, and since cars spend most of their life just sitting on their tires, you DON'T want any torsional strain on the bushings in that state.

This is why storing a car on jackstands is BAD advice. Set to the maximum cold air pressure placarded on the sidewall a decent bead seal should keep the tire from going flat for at least a couple of years, and beyond that it's a lot easier and cheaper to replaced old, damaged tires than damaged suspension bushings.

Duke

So guys, it's just the final tightening of the fasteners once grounded that you're referring to, not the actual installation process of the bushings into the metal cavity?

Correct... all nuts/bolts should be installed "finger tight" or a little more. Torque to spec when the car is back down on the ground and before torqueing roll it back and forth a few times until the suspension settles down to normal ride height.

Duke