Ferrari 412 rear shock absorbers

Having searched what I could find, I remain a little confused and hope the forum might assist my understanding. Apologies in advance if it has been covered - I could not find it.

I am told I need 4 new rear shock absorbers for my 1986 412. These are part number 117722, and all the usual parts sources we all use say they are NLA and unobtainium. KONI North America have also confirmed this, and appear unable to offer a solution. Several members have noted they switched to coil-overs (whatever they are) as the load-levelling versions are not available.

I have found several shops in the US that say they can rebuild the old ones ( between 6 weeks to 4 months to do so). So that's one option. Any recommendations for any specific shops would be welcome.

A second option is to switch to the coil-over type. Example: https://lbilimited.com/wp-content/uploads/2015/10/Suspension-Modification-Details.pdf

And a third option is "apparently" to use new KONI shocks without the load-levelling feature - their part number 82-1825SP2. I am assuming these will be correct dimensions to fit the car, without using the plumbing in place? If the new KONI shock is the NON load-levelling type, what do you do about the oil lines and connectors plumbed for the original shock - remove?, cap and seal? etc?

My question is which way to go? My understanding is that the "central" levelling cylinder (part #117737) was the "driver and controller" for the rear self-levelling - would this still be the case with the outer rear shocks switched to the non-levelling type? Will it function ok?

Not a big consideration, but last, I would assume if the setup becomes non-original, there would be penalties for FCA concours judging!

Apologies for the long post - would appreciate your suggestions! Thanks, Oliver

 

Good day,

This has been discussed before, but for the older cars. I saved the thread, as I found a lot of good info and so hopefully it will answer some questions for you:

https://www.ferrarichat.com/forum/threads/replace-self-leveling-suspension-with-something-modern-need-steps.527434/

I have not got to my car's shocks yet and so I cannot provide any feedback on the options presented. Please post up what you end up doing.

Cheers,

Sam

 

The 412 des not use the same loadleveling unit as featured in the previous models. On the 400i gen 2 and 412 the system is a Citroën patented solution that was also used in Mercedes and RollsRoyce. Unlike the older system, this is not a self contained unit: so it rougly consists in 4 parts:
1) A pump
2) Two pressure accumulators (a.k.a "sphere")
3) Two "Shocks"
4) A sensor (see the lever that's under the spare wheel)

This system is really nice and I would not replace it with coil-overs. Issues with these systems are either related to either the sensor being stuck by dirt, or a "flat" pressure accumulator. Some companies can refill the accumulators (with nitrogen?), but chances these are now porous beyond repair. They are similar to the accumulators used in the old Mercedes (500/560 SEC, SEL), except for the fittings. There are some reported success with Mercedes 500/560 accumulators. No idea if the pressure is correct, but as said some shops can empty/refill the accumulator.

Please note that I have experience with the Mercedes M100, not the 412 or even the Mercedes 560, looking at my cousin's 412 I can say the system are indeed very similar, but I never personally swapped parts from one car to another. Getting in touch with a Citroën specialist is probably your best bet (as we did with the M100).

 

My Citroën mechanic is long gone, but here is a link to a company based in Paris which is dedicated to refurbishing these suspensions. "http://www.hydrosphere91.fr/lasphere.htm" with the corresponding prices "http://www.hydrosphere91.fr/tarifs/cx.htm". These prices are for mainstream Citroën cars, so one can assume that the price for a prancing horse will be more significant.

A mechanic with RollsRoyce experience could probably be of some help. For a U.S based solution, maybe Karl Middelhauve would accept (?) to service the accumulators or provide hints on who could do it: he is a Mercedès M100 die-hard, so our suspensions do look pathetically simple compared to what he is used to...

 

Usually the shock absorbers itself are not the problem. They are not even shock absorbers in the proper sense. If they are not leaking and moving they are probably fine. All damping is done in the spheres or accumulators. I am pretty sure that every accumulator in every Ferrari 412 today is broken when not repaired.

I had mine reproduced by a company in Germany. They checked if the old ones can be refilled but as expected the rubber membrane inside the accumulator was gone.

I refreshed my whole rear suspension and it was really worth the effort. The ride quality has improved dramatically. And even after 3 months in the garage the ride hight on the rear axle is unchanged. The car does not lower itself when time goes by.

Some pics

old accumulator
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new accumulators - bad pic from the manufacturer, my mechanic did install them without taking a pic so this is the only one I have....

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other parts

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installed

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That last photo is absolute art. Someday mine too will look like that.

 

Agreed... Those pics of the restored suspension are fantastic!

Cheers,

Sam

 

Changing the bowls on a 412 was fairly straight forward once the details were worked out. The new bowls are off an old Merc SL. You have to make a new bracket for them as the mounts are different, and block off one of the holes in the bowl itself.

Found a couple of pictures I took.

Any judge would be hard pressed to spot this replacement if the car was on the ground !

Mark

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From an old thread some pictures that show the MB spheres installed and the bracket
https://www.ferrarichat.com/forum/threads/365-400-412-dna.187900/#post-137510862

 

Would you mind sharing the info for the shops that can rebuild the shocks please?

I have a 1984 400i and one of the rear shocks has started to leak a small amount. Figure I should send all four out for rebuilding at once.

Anyone else have any experiences RECENTLY with a shop that rebuilt 400i shocks? Many older threads on here, but not many recent. Not interested in converting to coil overs.

Thanks!

 

Hi Jason,
I had Performance Shock in California rebuild all of mine. They were great! I'll try to post some photos.
http://performanceshock.com/index.php?main_page=product_info&cPath=1_765&products_id=3965
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Excellent! Thanks!

What was their turn around time?

 

4 weeks.

 

That's fantastic! Mine are route to Ferrari in Sacramento CA - recommended by a fellow FChat 412 owner whose were done last year. He was also very pleased with their work. Contact there is Doug Axt, very helpful. He's doing the 4 shocks plus the centre hydraulic control arm too for me. I'll try to post when the refurbished parts are installed. Just to also mention, I ordered the rear suspension complete bushings kit from Eurospares in the UK, free shipping, and about half the cost of the same items from Ricambi.

Sent from my BBB100-1 using FerrariChat.com mobile app

 

Should have said Ferrparts, in Sacramento California. Expected turnround time - 4 weeks.

 

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Finally they're finished and in transit as I write this! Thanks to Doug Axt at Ferrparts in Sacramento and Bruce at Performance Shocks at Sonoma.

 

My 412 has the same problem but going a somewhat different route

I am leaving the hydraulic system in place and will connect as if in full use.
In reality use modern shocks including ride height control.

The prototype is already done and drove well but some additional tweaking was done.
The Ferrari Specialist doing this is going to document it in full and provide a complete kit.

Obviously I can place put my experience in here and provide the shop details when done.
Any 412 owners that want to visit the Netherlands can test drive my car to experience the setup.

Expect the car to be ready within next 4 to 6 weeks.

 

Hi guys, me again. So the overhauled shocks are great, but on my last drive recently, I experienced a huge fluid leak from the left rear line (tube) and it seems the fitting to the front (of the rear) shock is not able to fit the shock properly. Part number 117738. Checked with all the normal suspects, and it's unobtainium and no longer available from the factory. Am investigating possible remanufacture of new tubes with the helpful people at Scuderia Rampante and Performance Shock. Also checking on used parts from cars being broken (Eurospares etc). And wondering that if I could instead even find the (shorter) tube 117739 I might be able to use its fittings but replace the shorter tube with the longer required length. Any other suggestions please?

 

Hello,

how did it go and can you share pictures of your setup?

 

SO... the end result is the original system is now up and working well as originally designed.But iIt was completely impossible to find new required hoses to replace the one that was leaking.

The long story - I had searched high and low in Italy, Switzerland, France, the UK, Canada and the US to no avail. My repair shop thought they had found a new NOS one in Switzerland, ordered it and when delivered it was the wrong part. My good friend in the UK (who has had a 308 GTB fibreglass, a series of Daytonas, and presently a 599GTB) has had a relationship for over 40 years with the nice people at Sauro in Bologna Italy, a Ferrari authorised shop https://www.autofficinasauro.com/en-gb I met them when we both went to the factory visit 18 months ago. Even these people, who have intimate long relationships within the factory could not come up with a "mere" hose.

So, I asked Performance Shock (who originally rebuilt all my shocks etc) if they could help. They also could not source the hose, but thought they could design a workaround so the original suspension system would be maintained. And yes, with their access to a (secret to me)vendor in the UK, they came up with banjo bolts and fittings (picture) that would allow me to make up the correct line length and clamps, so that it would substitute for the original. I have bought the entire kit.

Meantime, I continued to search for a used original line - and got lucky! I found one original line at GT Performance Parts in Arizona - and when I asked, they had two "good used" long lines for the leading shock, and one short line for the rear shock. I have bought them all.

I remain frazzled but relieved I was able to sustain the original system design, but my goodness it's getting harder!

BTW, the 412 run sand rides great now - and doesn't sag in the rear when parked and engine switched off.

Long story short - I highly recommend Performance Shock in Sonoma California (Jayme Perreira and Bruce Ritchie) and GT Auto Parts in Phoenix (Bill). Both were life savers!
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Having hoses fabricated is a pretty common thing from cars, aviation, trucking, industrial applications, you name it. Should not be hard to find. I generally do not buy new hoses for a Ferrari even if they are still available.

 

Exactly, it is just a simple hydraulic hose, why all the fuss?

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The hose was never the problem. It was the particular and peculiarly angled fitting.

 

Good day ONSilver,

Why could they not reuse the original fitting when making a new hose? Was the original fitting damaged?

Cheers,

Sam

 

Good day 360modena2003,

For this application I agree. However... just a heads up... if you try and do the same for our oil lines (engine to oil radiator, etc) then it is not so simple for two reasons. First, a lot of (engine) oil rated hoses are not designed to operate at the temperatures our oil can reach. Secondly, these days the majority of the pump fuel contains some level of Ethanol (which does make its way into the oil) and a lot of the oil rated hoses will breakdown when Ethanol is present. I live in an area which eats, lives, and breathes oil and even though we have 50-60 shops that can supply and make pretty much any type of oil line, it was extremely difficult for me to find a shop (I found only one) that could supply hose that could meet the two requirements I mentioned earlier.

Cheers,

Sam