Is this the infamous actuator wire twist?

Yep

 

You have to take the actuator off to untwist the wire. There's a wire retention clip that has to come off first. After the wire is untwisted, the actuator is replaced. I find it easier to put the retention clip onto the actuator first making sure it's seated correctly in the slots on the actuator, then snapping the actuator into place. Finally, I test to see that it's secure.

 

Or do Dave's mods and never have it be a problem again.

Taz
Terry Phillips

 

John- Do a search for actuator in Tech Q&A and here. Also hyperblock.

Taz
Terry Phillips

 

The front right actuator on my 550 is incredibly twisted, by at least 10 turns. I have untwisted it by a couple of turns by disconnecting the cable, I'm afraid that by unwinding further the cables might break.

However, the front left is in mint condition, untwisted. I was therefore planning on swapping the actuators so that the twisted one doesn't take any further beating.
I understand from reading various threads that they can simply be lifted after the spring clip has been removed, and that they don't have to be put back in any particular angular position as the system resets them every time the engine is started.
Is this correct?

Thanks in advance,
Stefano

 

Yes

 

Us 575M owners miss out on all that actuator fun. Guess Mannesmann-Sachs knew what they were doing. Too bad it would be prohibitively expensive to swap the Bilsteins.

Taz
Terry phillips

 

I just leave my 550 in "sport" mode all the time and I've never had any twisting issues with the actuators.

 

I have pulled both front actuators out to swap them, and found a problem with the front right shock.
The little metal cog which is turned by the (twisted) actuator is partially broken, and that wouldn't be a big deal, as the system would still work.

The big problem is that the cog rotates endlessly in either direction, whereas the one on the left correctly rotates only by about half a turn.
Does this mean that I need a complete new shock absorber??
I'm surprised the suspension light almost never came on....

Stefano

 

Hej,

this little cog can be bought from ricambi america http://www.ricambiamerica.com/advanced_search_result.php?keywords=sag355&osCsid=0t13qmtofhjgsppdn1a0bv7hl1&x=0&y=0

it is the same for the F355, just make sure you mount it in the correct way otherwise the shock will be soft when the actuator think it is hard and so on, basically do not mount it 180 degrees in the wrong direction.

Mvh
Joakim

 

Thanks Joakim,
this is a relief!

The portion which has broken off in my cog is that containing the notch which acts as the end stop, that's why the shaft rotates endlessly.
So it seems I don't need a new shock for 1020 Euros+tax+work

)
Stefano

 

The front right actuator was so twisted that the outer (very stiff) sheath split open, exposing the wires.
All this torque twisted the wires, broke the damper's (cheap) metal cog, but not the plastic gears, how odd...

Stefano
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Update: I just drove my car for the first time after the long winter sleep, and the suspension light never came on.
I have replaced the metal gear on the right front with Ricambi's, and swapped the actuators.


Stefano

 

I keep looking for Dave's post on the actuator twist. Seem his fix is forever. Can anybody pass the link on.
Thanks

 

I've noticed that the metal cup onto which the actuator sits has two small holes at the bottom.
If a metal wire was passed through these holes and fixed to one of the four suspension screws, then the whole assembly should stop rotating.
The wire would sit low enough in the cup so as not to interfere with the metal gear.
This is just a theory though....

Stefano

 

After driving about 1000km the front right actuator has rotated by about 1/4 turn.
This is not much, at this rate I'll just need to untwist it by one turn in 3000km!

Stefano

 

My shock mount modification was never intended to solve the twisting actuator problem. the fact that it does prevent the shock rod/actuator from rotating is just a side benefit.

I never had the twisting problem, I had a ride compliance problem caused by worn shock mounts in the rear which I solved with my modified shock mount.

When I did the same modification to the front shocks I realized that there now was no way for the shock rod to rotate thus curing the twisting problem as well.

When you do some research you find that the bump rubber configuration in the front is different from any other shock bump rubber on any cars except for the 355 Challenge cars. On the 550 front the bump rubber is attached to the shock mount rather than being free to slide on the shock shaft.

I decided that it can't be a coincidence that the only place an actuator turns is also the only place the bump rubber is attached to the mount. Remember that the actuator is positively attached to the shock rod therefore it's the rod turning in the mount's spherical bearing that is the real problem. I believe its the bump rubber configuration that causes the shock rod to turn.

The problem is that it's all but impossible to remove the bump rubber and replace it with a conventional bump rubber (like the rear shocks) without destroying the shock mount bearing which would prove my theory.

Here is the link to the shock mount modification. Its not really that hard to do if you have access to a lathe and some basic machining skills.

http://www.ferrarichat.com/forum/showthread.php?t=244510&highlight=shock+mount

Here is a link to a post from a member I did the modification for.

http://www.ferrarichat.com/forum/showthread.php?t=267473&highlight=ferraridriver