pictures and tips for replacing engine lid struts with SG404018 units

I recently bought a '91 348ts. I'm going to take on the small DIY maintenance items that I can and leave all the important stuff to a shop.

In searching the forums for replacing weak engine lid struts, I couldn't find all the detail I wanted. Here's a writeup that I hope will help the increasingly rare owner out there who still has factory original struts. I'm gonna provide tips that I wish I had while doing this. I'm backing up these pictures on my Google account for long term availability.

The Sachs SG404018 strut is much cheaper than the Ferrari-specific part, and has easier to use ball joint securing clips. If you're going to keep maintaining your car, you might as well switch to the SG404018, even if it pushes up a little strong.
You can get it on RockAuto here: https://www.rockauto.com/catalog/moreinfo.php?pk=576779
I suspect RockAuto will be here even after the bombs drop and only roaches crawl the earth.

Here's a comparison of the factory strut and the Sachs:
https://lh3.googleusercontent.com/-odsWV14JMIw/Vf0Md4diejI/AAAAAAAAMYU/OFIiEciZIFY/s576-Ic42/1%252520-%252520Camera%252520Upload.jpg
I thought I had done a better job of lining up the bottom ball joints, but as you can see, they're very close to the same length. Note that the piston body of the Sachs is wider. This factors in later.

A shot of the 348 engine lid lifted up (with the replaced struts):
https://lh3.googleusercontent.com/-GpFjj17jvwg/Vf0MdyktchI/AAAAAAAAMXs/hNlt7QBbPNk/s800-Ic42/2%252520-%252520Camera%252520Upload.jpg
Anyone looking to DIY should be able to find the struts easily. Note that both struts have their bolts and nuts mounted facing left.

Tip: assuming you're replacing shot struts, you don't need to worry about not scratching up the bodies of the old struts while unmounting them. Be careful not to bang into other stuff in the engine bay, of course, like the hoses and wiring looms all around the struts.

This next series of pictures is what I really wish I had -- a closeup of how the factory ball joint retaining wire works.
https://lh3.googleusercontent.com/-R9C4Y-qA8Eo/Vf0Me8fsf8I/AAAAAAAAMX0/ihJ0g-jdrlU/s576-Ic42/6%252520-%252520Camera%252520Upload.jpg
The wire goes across the face of the cup, holding the ball in place. I bet it'd be possible to pry the cup off the ball, but I didn't feel safe using that kind of force in situ.

More pictures to show you how the wire wraps around the base of the cup:
https://lh3.googleusercontent.com/-rWDjFfBPGqE/Vf0Md_8xcHI/AAAAAAAAMX8/8ALwSHRq1T0/s576-Ic42/3%252520-%252520Camera%252520Upload.jpg
https://lh3.googleusercontent.com/-KHAKIG9lSlU/Vf0MekDNlaI/AAAAAAAAMYE/qUAVz0WlXVI/s576-Ic42/5%252520-%252520Camera%252520Upload.jpg
https://lh3.googleusercontent.com/-cWfToei7I7U/Vf0MeVHLVoI/AAAAAAAAMYM/dyoHqMbVeCQ/s576-Ic42/4%252520-%252520Camera%252520Upload.jpg
In the last two pictures, you can see the end of the wire that you need to grab to undo the wire from the cup.

The needle-nose pliers I was using did not have great grip, and space issues meant I couldn't use certain angles. You'll have to play around to find a way to grab onto the 'cobra head' end of the wire.
Because you don't need to keep the wires or struts, you have same leeway to clamp hard around the C shape of the wire and pull away from the cup. Once you've got the C shape free, you can use your fingers to pull the wire along the axis of the strut away from the cup. This will free the imprisoned ball.

Tip: don't forget to have something propping up your engine lid. A work light or being outside will let you actually see what you're doing.

Recommended unmounting order is:
- right top joint
- right bottom joint
- left top joint
- left bottom joint

I'm right-handed and found it easier to access the space around the cups when leaning on the right side of the car. I figure it's easier to get familiar with the procedure on the easier side first.

When you undo the top ball joint, you can lean the strut against the intake manifold or hosing. It's not very heavy. When you undo the bottom joint, then you can just take it out.

Tip: Leave the two ball joints bolted to the engine lid supports and firewall. You can install the new struts against the old ball joints.

If you got this far, congrats, you're pretty much in the clear. Installing the new struts is a cinch.

Apologies for not having an actual picture of the SG404018's cup. Here's a generic picture:
https://lh3.googleusercontent.com/-tr1YSnG1ANM/Vf3IanrfdAI/AAAAAAAAMa0/Dg2sodfl-JM/s500-Ic42/A4DiliS.jpg
Each cup has a metal C-clip wrapped around the back of the cup opening. The ends of the clip are "teeth" that clench around the ball joint and secure it. The C-clip has gaps under it where you can pry up with a narrow flat blade screwdriver or similar implement. Be careful that you don't push the C-clip off the cup -- it holds itself in place by tension once you pry it far enough open. My cups appeared to be pre-greased.

To put in a Sachs strut, you just need to have the C-clip pulled back as you place the cup over the ball. I did this two-handed -- one hand holds the strut and the other has the screwdriver prying the C-clip open. Maneuver the cup over the ball and press on gently. The C-clip should yield and let you slip the cup into place.

Orientation -- this is what caught me off guard. Other threads have discussed whether to mount the strut with piston body up (factory orientation and probably prefered) or piston down. My Sachs struts have a wider piston body. That body pushes against the engine lid support bracket that the strut installs on. If I mount mine piston up, I can't get the necessary angle to install the other end. So I have no choice to install piston down, even if that's worse for wear and tear. I'm ok with that if they last a couple years.

Recommended mounting order:
- left bottom joint
- left top joint
- right bottom joint
- right top joint

Honestly, this part was a cinch. I did a quick check that the ball joints were bolted in firmly, but popping on the cups was easy once I knew I used the only possible strut orientation.

The engine lid pops up pretty snappily with the new struts. They're about 10% higher force than the factory struts. Some people have suggested replacing just one side at a time to dial back the strength some to reduce whiplashing the engine lid supports and lid itself.
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Long term review update:
Over the last few rides, I've noticed the struts are lifting the engine lid up a couple inches and then stalling. Even a fingertip's worth of help will get them moving, but I can't say I'm thrilled that they're already this weak in a year's time.

Given that when the lid is closed, there's probably not that much of a difference in sealing or how much heat cycling is applied to the strut piston-up or piston-down, I dunno if that's really the major issue. Likely just the quality of the strut itself.

I'll update again when I think these guys have to be replaced again.

 

I wonder if I just got a bad one. It's annoying to test them since they're still not easy to compress by hand. You've got the same model number?

 

Sadly, I don't know where I put my factory struts. On the flip side, with these Sachs, why rebuild when they're $25 for a pair shipped?