Tighten suspension components with load on them?

Getting ready to install a RC leveling kit on my truck today. I’m pretty mechanically competent and judging by the videos I’ve watched, the install looks pretty easy.

One thing I don’t see many people in videos doing - but I keep hearing is important - is to give a final tighten to spec on everything AFTER it’s back down and has a load on it.

What’s the reason for this, and which parts do I need to make sure I re tighten in this manner? I would assume just anything with a rubber bushing?

 

Roger on the Rubber bushings and I can see a good reason other fasteners as well. If there's any play you'd want it out in the normal position. May keep the alignment closer to specs longer.

 

I will be getting it re aligned Saturday, but I guess I understand the load taking out and play before tightening.

 

Don’t fully tighten the suspension components until they are on the ground in the normal load position. If you tighten them while on Jack stands at full droop, when you let it down, the bushings will have a twisting force applied to them constantly and wear out fast. You want them tightened at load so they will be in the normal position all the time and only twist when the suspension travels up or down.

 

Doing the final tightening & torqueing down of suspension components on the ground is pretty common. Suspension components under load are essentially in their natural "resting place", if that makes sense.

In addition to what @KNABORES said above about rubber bushings: If you tighten suspension components while the suspension is hanging in the air...you'll be tightening / torqueing against the downward weight of the suspension components themselves. That means you won't actually be hitting really accurate torque numbers. At least, this what I was taught when I worked in a shop ages ago. It has stuck with me and I've done it ever since.

 

In addition to what others have said, you may also get noises if you tighten in the air. Its was super common on the Jeep Liberty forums I was on. Someone would install a lift, then they would post about all the creaking they were getting. Then they would get 10 replies asking if they tightened it on the ground.

I actually think that when I had my F150 aligned recently they might not have tightened under load because the thing creaks like an MF'r ever since.

 

Agreed. I always *try* to get a torque wrench on suspension components that have bushings with tires on the ground. UCA's are a problem, hence why they have bushing lube for the install I guess.