Join Date: Apr 2000
Location: Danville, CA USA
The reason Bilstein says to not use an impact gun is due to the internal friction they can cause in the dampers inner seals. In the Vorshlag video, note that Terry holds the strut shaft so that it can not spin while the impact is tightening the nut. This is really important.
If you can't hold the shaft to keep it from spinning, then do this.
Have the full weight of the car on the tires. This will cause the strut shaft shoulder to push up against the bottom of the c/c plate bearing. This adds a lot of friction to help keep the shaft from spinning.
Hold the center of the strut shaft with an allen wrench. Use a box end wrench to tighten the nut until it stops (no clearance between the bottom of the nut and the shaft spacer below it).
In most cases, you can then use a torque wrench on the crow's foot. There will be enough friction in the system. It is very important to push down as hard as possible on the allen wrench so that it doesn't climb out of the hex hole in the strut stub.
If the allen wrench does start to rotate in the hole, use an impact gun on the nut, but only pull the trigger for 1 second max. Since the nut only has to rotate maybe 5-10 degrees at most, holding the gun for longer will only heat up the seals inside the strut.
If you are installing struts which are adjustable, they will probably have a hollow shaft for the . If you use an impact gun on them, there is a very good chance that the top of the shaft will shear off. Don't do it.
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