suspension bolt torquing question

[Mr. V]

The manual says when working on the front suspension of my 740 to not fully torque the bolts for the radius rod and control arm bushings.

It says to put the bolts in not fully torqued, then put the car on the ground, push it sideways a few times, then torque the bolts to spec.

I understand this is to let the bushings find their sweet spot before tightening.

My question: when I do finally torque them, must the suspension be fully compressed, i.e. with the full weight of the car pressing down, or is it OK to first put it on the ground, push it sideways, then jack up the car and put it on jack stands with the front suspension dangling down and then tighten to spec?

Not sure how a home mechanic without a lift or ramps could do it otherwise.

[cwdodson88]

I feel like you want them fully weighted. I always use stacked 2x4 wheel cradles. Lift the car a corner or end at a time until all for are up in the air. Then do what you need to.

[toms_elleck]

You can usually weasel a wrench up there to tighten them up with the car on ramps.

[Harlard]

You can also load up the suspension with jacks or carefully set it down on stands with the jack in the middle as a safety measure, tighten, put wheels on, drop.

Ramps or stands are the better solution but can be inconvenient to store.

[gsellstr]

You absolutely should tighten them with full vehicle weight on them, IF you are using rubber bushings. Poly isn't affected by this as the bushings can pivot.
The reasoning is the rubber bushings are bonded to the inner and outer shells.If you tighten them with no weight on the suspension, when you lower it, you've now rotated the parts, putting a significant stress on the rubber as the inner and outer shells twist in opposite directions. If you tighten with normal weight on the suspension, the bushings only see the normal up/down movement of driving, with the exception of being the occasions when the vehicle is lifted off the ground.

[Harlard]

Originally Posted by gsellstr

You absolutely should tighten them with full vehicle weight on them, IF you are using rubber bushings. Poly isn't affected by this as the bushings can pivot.
The reasoning is the rubber bushings are bonded to the inner and outer shells.If you tighten them with no weight on the suspension, when you lower it, you've now rotated the parts, putting a significant stress on the rubber as the inner and outer shells twist in opposite directions. If you tighten with normal weight on the suspension, the bushings only see the normal up/down movement of driving, with the exception of being the occasions when the vehicle is lifted off the ground.

Correct, they will tear up in no time.

[Mr. V]

Thanks.

I don't have ramps, so will probably ask the guys doing the alignment in their shop to tighten to spec while they have it fully weithted on a lift.