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YOUR RESEARCHForged style coffin arms must be used with thick flanged tuning forks?
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Replace supplier
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Performed · outcome unconfirmed · Original poster
Porsche has changed the supplier for all the parts concerned � previously cast parts, now forged parts.
Forged style coffin arms must be used with thick flanged tuning forks?
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Performed · outcome unconfirmed · Original poster
We have been unable to identify any reason why the new design must be used exclusively for both part numbers.
Forged style coffin arms must be used with thick flanged tuning forks?
Use meyle part made
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Performed · outcome unconfirmed · Original poster
In my refresh, I used the Meyle equivalent of the new forged style, however I didn't know about the new tuning fork, and instead used the Meyle part made with the original flange thickness.
Forged style coffin arms must be used with thick flanged tuning forks?
Use original air ducts
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I fitted the new style LCA and tuning fork (genuine Porsche parts in my case) and re-used the original air ducts.
Forged style coffin arms must be used with thick flanged tuning forks?
Use together
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It's easy: intended pairs of designs of coffin ⚰️ and tuning fork control arms must be used together.
Forged style coffin arms must be used with thick flanged tuning forks?
Use /okay'ing
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Suggestion
The reason for Porsche retrospectively using/okay'ing use of 991 designs for replacement on 9x6 most probably is not an engineering decision but a commercial one.
Forged style coffin arms must be used with thick flanged tuning forks?
Use forged coffin arm
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Suggestion · Original poster
The forged coffin and original style tuning fork installed fine on my car, but now reading the bulletin, it seems to imply that the new style coffin arm and tuning fork need to be used together, ie it would be incorrect to used the forged coffin arm with thin tuning fork (or thick tuning fork with cast coffin arm).
Forged style coffin arms must be used with thick flanged tuning forks?
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I recently did a refresh on my front suspension, but a technical bulletin from Porsche is making me wonder if the parts I used are compatible:
Porsche Bulletin
. Porsche is now making a new forged coffin arm (
99634105320
) plus a front tuning fork with a thicker flange (
99733104302
). In my refresh, I used the Meyle equivalent of the new forged style, however I didn't know about the new tuning fork, and instead used the Meyle part made with the original flange thickness.
The forged coffin and original style tuning fork installed fine on my car, but now reading the bulletin, it seems to imply that the new style coffin arm and tuning fork need to be used together, ie it would be incorrect to used the forged coffin arm with thin tuning fork (or thick tuning fork with cast coffin arm). Does anyone know why these parts would not be compatible?
Yes what you used is fine. The center bushing height did not changed. The updated fork does require a longer bolt regardless of using the newer or older LCA.
Edit: It does seem by reading the TSB that the difference in the bushing could be the need for a beefier fork. So maybe it should be used. Or maybe the outer bushing is in a different place.
You would need to find out whether Meyle advises against your combo or not. Theoretically the Porsche bulletin will have no bearing on your case as you use Meyle parts.
Having said that, the risk of bending/breaking the flanges on the tuning fork, if combined with a coffin arms, of which the height/thickness of the bush in it is too small comes to mind.
The new Meyle parts are copies of the updated Porsche design. The bushing height stayed the same so that's not where the concern comes from. The only difference in the fork could be the strength or if they changed the length to mate with a difference on the LCA.
This doesn't help you as you've already purchased the new style arms but for posterity the Febi coffin arms and Dansk tuning forks are still made in the original design. These are readily available on FCP Euro and if you dig deeper can maybe find them elsewhere and save a few $$. I recently purchased these as I did not like the idea of being locked in to the new design taken from another car which is quite recent and less of a known quantity. As well as needing to replace everything at once and not being able to reuse my originals, even if temporarily, in case of any issues with the replacement parts.
Thanks for your responses everyone. I figured it was all right but wanted to check if I was missing something because of that bulletin. I might try sending Meyle an email just to see if they have any thoughts on the matter.
Maybe the bushing being stiffer? Or a different material that impacts the stress differently. The fork only connects to the bushing on that end so it seems it would have to be related. I use the old version with solid bushings and a lot of track use without issues.
I did contact Meyle, and they did confirm that, at least as far as they are concerned, the two revisions are compatible:
Porsche has changed the supplier for all the parts concerned � previously cast parts, now forged parts. We have also updated the design for both control arms [phone removed] and [phone removed]) accordingly. We have been unable to identify any reason why the new design must be used exclusively for both part numbers.
From a technical point of view, you can use either [phone removed] or [phone removed].
Did Meyle reveal whether their revised design of the coffin arm is forged or cast?
Just curious if they have invested in the much more expensive tooling for a forged part.
it�s good to know my initial thought of compatibility seems to be correct. The new bushing is 43 mm which is the same height as the old bushing. I do agree if you�re going to replace one side of the axle, replace the other with the same part.
I will say that most of those parts even the old ones seem to be fairly durable.
I recently refreshed my suspension with the new style tuning forks and old style coffin arms (bought when FCP Euro had a discount on the arms). Everything came together fine and I have been driving the car without any issues.
The center gap distance between both style tuning forks are the same. The only thing to note is you have to buy new bolts with the new tuning forks. The old bolt will not be long enough due to the thicker ends on the new design.
That explains my recent experience, but on the plus side FCP Meyle kits come with some, but not all, bolts and nuts. I ended up with extras at the end.
This does explain alot when I ordered kits from FCP last year to do my suspension I assumed they sent me the wrong forks for the 996. I returned them and purchased the thinner ones. Both the ones they sent me and the replacements I ended up installing were Meyle.
I initiallly received
MEY-4160500029 coffin arms with
MEY-4160500038 control arms. When I noted these control arms were thicker and the original bolts would not go through i exchanged for the thinner version.
I do hope that the older style Meyle control arms are ok because after a very short time I did develop a creak in one of the fronts that was coming from the coffin arm . Replacing the coffin arm solved that, for now. I cant see how using the thinner forked control arms would be a problem as it matches the original design I guess time will tell
You won't have a problem.
On another note regarding design updates on the tuning fork. The update through the 997 version meant that the 996 plastic air duct to cool the brake disk would no longer fit without cutting.
Is that also the case with the latest version of tuning fork?
I hope your right
How does this read to you
https://www.fcpeuro.com/products/por...yle-4160500024
This updated control arm from Meyle closely resembles the factory redesigned fork arm from Genuine Porsche. This updated arm is an excellent upgrade and refresh option for your Porsche Use with arm MEY-4160500029 for 996/986 applications. Please see TI 44/17 for more information
https://static.nhtsa.gov/odi/tsbs/20...037-0001.pdf**
I may be overreading it but it seems to suggest if you are using the new Myele design you also must use the newer fork that is thicker?
You're not overreading it, you understand the message.
It's easy: intended pairs of designs of coffin ⚰️ and tuning fork control arms must be used together.
There must be no gap between the fork and the bushing (in coffin arm).
Your chosen pair of the original designs works.
The reason for Porsche retrospectively using/okay'ing use of 991 designs for replacement on 9x6 most probably is not an engineering decision but a commercial one. Reducing the number of different p/n's in stock and the ability to place orders with greater volume with their supplier all lowers cost per part.
I'm probably the only person here who thinks this but it appears to me as though the new forged LCA requires the thicker tuning fork. They're meant to work together.
Having been through this during my suspension refresh I will also add that the longer bolt required is 95mm (versus the old 75mm bolt).
I do appreciate what everyone is trying to explain to me ,and im sure people want to kill me for this, but I get what you are saying. The bottom line though is the thinner fork fit perfectly on the newer coffin arm and others have verified even the busing is the same thickness as the earlier one so I do trust im good.
I just had some pause because it is interesting that after my refresh with correct install, etc. I developed a creek right over the union between the fork and the coffin arm on 1 side. Replacing the coffin arm solvd it. Could be a coincidence and even new parts can be defective.
