Huge Suspension Damage from High Tire Pressure?

Remember that this may be an ebay part. It may have been on the edge of failure when it came out of the box. But, you are right. Tire pressure is not a factor in any sway bar link.

 

The first step on removal of the sway bar or end links in the Haynes manual available at all major auto parts stores is jack up and support the front of the vehicle and remove both front wheels. I stand by my method. So the only thing left to do is agree to disagree.

 

Just an example, where suspension is supposed to be under load before bolts are torqued:

FWIW, from the Repair Manual instruction for 3rd gen Prius lower control arms:


I'm unclear as all heck as to what they mean by "temporarily tighten". Is that maybe a euphimism for "finger-tight", or "snugged"?? But anyway, they definitely want the car on the ground (and bounced a few times) before the full torque.

 

I see this in another Toyota doc:



Again, maybe finger-tight, or hand-tight?

 

The goal in situations like this is to allow any rubber bushings to be finally torqued while they are in their nominal position, so there is no constant pre-load on them that may prematurely cause the rubber to tear or to skew the alignment.

So in the pre-tightening step, you want thing tight enough to hold things in place while the fully assembled suspension is loaded so it takes on its nominal geometry. But loose enough so that the bushings will be able to freely rotate into their stress free position during that process. Hence the bouncing - to encourage stuck things to break free and move.

If you can easily put the car on a lift with its wheels on, that's one way to do this pretty easily. Do the work, do the pre-tightening, put the wheels on, lower it to the ground, bounce it a few times, drive it onto the lift, up in the air for final torquing.

Not having a lift, what I do as an alternative is to jack the wheel up before final torquing (*). For example, car jacked up in front, front wheels off, both sides on jack stands ... with a screwdriver or two stuck into the brake rotor slots to prevent rotation, wheel still off, I jack up the underside of the brake rotor. You can do that until the hub-to-fender distance exactly matches the meaurement you took before you started this job, or you could jack until the car barely lifts off the jack stand - either way, it will be just about exactly the same point. And that point gives you the same geometry as you have when sitting on the ground, which is what matters.

Many joints have no sense of a zero / home / rest position (e.g., ball joints). So those don't matter. Rubber bushings, where the inner sleeve is clamped in place by the torquing process, the outer sleeve is fixed in the suspension part, and rubber is in between, are the other common type, and those definitely do have a zero / home / rest position. As long as you understand this concept, it's usually pretty easy to figure out whether a particular joint needs to be geometrically zeroed before final torquing. If you're not sure, then zero things.

(*) not wanting to get it too complicated up there, but for situations where a sway bar may be a significant asymmetric issue, that can be addressed as well by jacking the other wheel, or by torquing without the sway bar attached.

 

Yeah that's what I'm thinking. Maybe they need some more English editorial oversight, expressions like "temporarily tighten" is probably enshrined as the translation to use, but I would think it leaves the typical English reader scratching their head. "Hand tighten only" or something like that might clue readers in.

And if all this text wasn't behind a paywall, maybe shops would stand a better chance of getting it right...

Regarding the method for loading the suspension AND having enough room to torque the bolt: how about setting it down onto ramps, or would that throw it off-level enough to matter? I guess the other end could be jacked up and onto jack stands. Or onto a second set of ramps.

 

Ramps should be just fine. The fore-aft level does not matter here. Sometimes though, having the wheel off gives better access, even when you can do the ramps or lift thing with wheels on.