Bilsteins both going into and coming out of MacPherson struts...
a) 1st Screen-shot details some notes and explanations from the Bilstein catalog (I've high-lighted the requirement for no tension on the top-mount prior to removal). We are here (below) going to expand our understanding of that warning.
b) A cautionary tale about a UrS-sized yellow Bilstein damper half as projectile we should all be aware of...
https://www.s2forum.com/forum/techni...em#post2111150
c) A listed caution from Bilstein.com (although the subject damper construction details, configuration and specific eject-able part name may differ from the example shown in Bilstein's photo (1st screen-shot below), this factory warning is still applicable here), see note regarding risk of piston-rod ejection (clearly a factory known possible hazard, we simply have failed to pick up on their long pre-existing instruction), and Igor's experience (albeit an UrS one) above is a very lucky example. What comes to mind is that if you don't know whether your dampers were always installed (or particularly removed I would think!) using the approved two-tools by hand only factory method, you may want to proceed as if someone did use an impact-gun in the past.
While still on the car, B-series car's struts would (fortunately) only be able to blow-out downward, as they are constrained by the small hole diameter of the fender-turret receiver for the top-mount et al, while C-series cars strut's top-mounts appear to be remove-able from the top of the still installed strut, posing the possible hazard outlined above. In either case we now see that it may be wise to always remove all weight from the wheels, allowing the suspension to fully extend, so that tension against the top-mount can be checked as absent; prior to strut and top-mount removal.
Understanding that both ends of the the skinny and hidden internal piston rod are threaded, one into the base of the yellow tube and then staked in place to help prevent exactly this issue (see photo in post 15 above), the other is fastened to the piston with a nut (3rd, 4th and 5th screen-shots). and that the possible undoing of which (and the factory's unhappy experience) is likely the cause for the warning.
We must therefore always key the internal hex of the damper shaft to prevent it turning during top nut install and removal. Although somewhat counter-intuitive, it may also be that even during improper nut installation (with the use of an impact-gun for instance) that the factory thread-locking (at the piston to piston rod connection) is weakened or undone to the extent that, the damper becomes 'armed' for a possible future explosion at some point; if we are not watchful for something amiss during dis-assembly.
d) 6th Screen-shot below (from the excellent https://s2-audi.co.uk/tech_articles/front_shocks.htm) shows the factory method re the top nut.
e) 7th Screen-shot details (from) Koni top-nut torque targets and approved method, but also echoes an anti-impact gun warning / prohibition for this location.
Bilstein notes and explanations Screen Shot 2022-01-05 at 08.44.01.png Blstein install : removal tip Screen Shot 2021-11-13 at 12.50.50.png Bilstein piston attchmnt 1a Screen Shot 2022-01-05 at 12.45.45.png Bilstein piston attchmnt 2 Screen Shot 2022-01-05 at 11.56.43.png
Bilstein Mono tube piston to rod attachment cut away Screen Shot 2022-01-05 at 12.19.15.png https:::s2-audi.co.uk:tech_articles:front_shocks.htm Screen Shot 2021-11-13 at 13.47.58.png Koni top nut torques, method and warning Screen Shot 2021-11-19 at 11.08.46.png
a) 1st Screen-shot details some notes and explanations from the Bilstein catalog (I've high-lighted the requirement for no tension on the top-mount prior to removal). We are here (below) going to expand our understanding of that warning.
b) A cautionary tale about a UrS-sized yellow Bilstein damper half as projectile we should all be aware of...
https://www.s2forum.com/forum/techni...em#post2111150
c) A listed caution from Bilstein.com (although the subject damper construction details, configuration and specific eject-able part name may differ from the example shown in Bilstein's photo (1st screen-shot below), this factory warning is still applicable here), see note regarding risk of piston-rod ejection (clearly a factory known possible hazard, we simply have failed to pick up on their long pre-existing instruction), and Igor's experience (albeit an UrS one) above is a very lucky example. What comes to mind is that if you don't know whether your dampers were always installed (or particularly removed I would think!) using the approved two-tools by hand only factory method, you may want to proceed as if someone did use an impact-gun in the past.
While still on the car, B-series car's struts would (fortunately) only be able to blow-out downward, as they are constrained by the small hole diameter of the fender-turret receiver for the top-mount et al, while C-series cars strut's top-mounts appear to be remove-able from the top of the still installed strut, posing the possible hazard outlined above. In either case we now see that it may be wise to always remove all weight from the wheels, allowing the suspension to fully extend, so that tension against the top-mount can be checked as absent; prior to strut and top-mount removal.
Understanding that both ends of the the skinny and hidden internal piston rod are threaded, one into the base of the yellow tube and then staked in place to help prevent exactly this issue (see photo in post 15 above), the other is fastened to the piston with a nut (3rd, 4th and 5th screen-shots). and that the possible undoing of which (and the factory's unhappy experience) is likely the cause for the warning.
We must therefore always key the internal hex of the damper shaft to prevent it turning during top nut install and removal. Although somewhat counter-intuitive, it may also be that even during improper nut installation (with the use of an impact-gun for instance) that the factory thread-locking (at the piston to piston rod connection) is weakened or undone to the extent that, the damper becomes 'armed' for a possible future explosion at some point; if we are not watchful for something amiss during dis-assembly.
d) 6th Screen-shot below (from the excellent https://s2-audi.co.uk/tech_articles/front_shocks.htm) shows the factory method re the top nut.
e) 7th Screen-shot details (from) Koni top-nut torque targets and approved method, but also echoes an anti-impact gun warning / prohibition for this location.
Bilstein notes and explanations Screen Shot 2022-01-05 at 08.44.01.png Blstein install : removal tip Screen Shot 2021-11-13 at 12.50.50.png Bilstein piston attchmnt 1a Screen Shot 2022-01-05 at 12.45.45.png Bilstein piston attchmnt 2 Screen Shot 2022-01-05 at 11.56.43.png
Bilstein Mono tube piston to rod attachment cut away Screen Shot 2022-01-05 at 12.19.15.png https:::s2-audi.co.uk:tech_articles:front_shocks.htm Screen Shot 2021-11-13 at 13.47.58.png Koni top nut torques, method and warning Screen Shot 2021-11-19 at 11.08.46.png
Comment