Subframe Dropped and cracks found

[jet_dogg]

Agreed Martin.

I've been around a while, and all of the big 3 are overblown. Hell, even the cars with broken vanos exh hub tabs keep plugging along just fine. Intake bolts shearing or working loose is uncommon as well, and only afflicts 05/06s as far as I can tell. Way more 200k cars with original bearings than sub 100k with spun ones. Very very few reports of RACP issues after plates/bushings job - and even then we don't know how well the job was done in those cases. And at this point, it's not a case of "well, not enough time or miles have passed for us to know yet."

It's like people claiming COVID is deadly because the news says so and their over weight, diabetic uncle died. Reality is different than perception.

I think it will eventually affect all cars produced just at different rates. It's also a case of people not knowing about the internal chassis conditions of their cars. I am of the opinion, however, that the root cause of this is failed subframe bushings percussing against the panel with varying load inputs (and no less because of a loosely mounted differential twisting about its carrier).

Though contrary to forum dogma, I have solid diff bushings going in as well. Monoball everything on the street too.

[t3ddftw]

holy hell, at basic shop rates of $100/hr this is sounding more like a $5k job than the $3k I was kinda planning on. curious if others who have had this done have any feedback?

I'm about $2000 into this project doing everything except the welding. This price includes replacement bushings and balljoints for everything in the rear subframe.


My 2006 with 100,040 miles zero cracks and one spot weld failure (located on the topside of the RACP).

I installed the CMP plates along with their "Stage 1.5" plates which similarly to the Redish V3 tie the chassis legs to the RACP without a cross bar.

-Ted

[enjoy_m3]

Well, here is how I found out about my problem.

https://www.youtube.com/c/RedishMotorsportbmw/videos

You'll have to scroll through the older videos which they do explain failure points on the e46 chassis that Vince was also mentioning. They actually say all e46 chassis have this issue. They have a lot of videos with different varying types of failures on the e46. They're the only shop I know of that are doing this kind of extensive repair/restore on RACP.

I had reinforced subframe done by Kevin (kaiv). Took the car a couple of track days and upon pre-track inspection, I found small crack in the seam sealer. That's when I decided to get the vincebar and found the reddish motorsport videos.
And out of curiosity, I took off the seam sealer in the areas Reddish mentioned. There wasn't any visible damage until I took out the seam sealer and found the failed spot welds. I guess the only way to really find out if you have the issue is to remove the seam sealer in your car if you're willing to.

[lemoose]

It's like people claiming COVID is deadly because the news says so and their over weight, diabetic uncle died. Reality is different than perception.

Not sure what news you're watching/reading that is trying to convince you that the virus is definitively going to kill you. The main narrative I've gotten is that we don't have the infrastructure to reliably deal with .1-1% of the entire population being hospitalized for the same thing within a sub-12 month timeframe.

[Tbonem3]

Agreed Martin.

I've been around a while, and all of the big 3 are overblown. Hell, even the cars with broken vanos exh hub tabs keep plugging along just fine. Intake bolts shearing or working loose is uncommon as well, and only afflicts 05/06s as far as I can tell. Way more 200k cars with original bearings than sub 100k with spun ones. Very very few reports of RACP issues after plates/bushings job - and even then we don't know how well the job was done in those cases. And at this point, it's not a case of "well, not enough time or miles have passed for us to know yet."

It's like people claiming COVID is deadly because the news says so and their over weight, diabetic uncle died. Reality is different than perception.

[martin.oconnor]

Although I’ve learnt over the years that sometimes all the facts and evidence in the world is not enough, here’s an old archived thread of mine from m3f that explains this very well.

Sorry - but this is not 'all the evidence in the world'.

The question is not that this type of failure can occur - it is how likely is it to occur.

When I was deciding which subframe strengthening strategy to go with back in 2016-2017 I looked for evidence that this failure mode was common. I found just a smattering of reports (in contrast to reports of mount failures, which are legion). Many of these cars are approaching 20 years old now and if this were a common failure mode E46 forums would be overrun with reports. So I decided to use foam on the four mounts.

The cost/possible-benefit ratio of the above approach seemed well beyond reasonable for me, particularly given the invasive nature of the solution and reliance on the skills of the person installing it.

The notion that all E46 M3s are ticking timebombs that will eventually exhibit this failure model seems to go well beyond the empirical evidence.

[pawelgawel]

Thank YOU! appreciate all this info

[VinceSE2]

Tried pasting the content from the archive here, but no pictures come through.

But here’s one I copied to show you where the foam goes. And hopefully you’ll understand why it makes no difference




And here are two pictures that clearly show cracks and chassis separation on two different cars that where plated

[VinceSE2]

Mybe Im playing devil's advocate here, id like to see the extent of damage after plates are done and foam. I haven't been able to pull up any examples mysefd, maybe someone can post some links?

Although I’ve learnt over the years that sometimes all the facts and evidence in the world is not enough, here’s an old archived thread of mine from m3f that explains this very well.

It contains at least 5 examples of cars that, even though they have been plated (foam makes no technical difference as it strengthens the same area as plates), have failed just like I have described.

Please be aware though that this takes a while to load as it’s in some sort of archive.
So anyone interested in reading it, PLEASE BE PATIENT
Also, it won’t open inside of Tapatalk

https://web.archive.org/web/20170731214304/http%3A//www.m3forum.net/m3forum/showthread.php?t=555302

Sent from my iPhone using Tapatalk

[lemoose]

Mybe Im playing devil's advocate here, id like to see the extent of damage after plates are done and foam. I haven't been able to pull up any examples mysefd, maybe someone can post some links?

I had the welds in my wheel arches completely fail on me after installing plates and the entire RACP was pulling itself out. the root cause has already been well explained to you so i have no idea how anyone would arrive to the conclusion that plates address the issue but you do you boo

[martin.oconnor]

Mybe Im playing devil's advocate here, id like to see the extent of damage after plates are done and foam. I haven't been able to pull up any examples mysefd, maybe someone can post some links?

I'm also deeply skeptical of the need for such elaborate solutions. When doing my car I decided to foam all four mounts and leave it at that. (You can find my write-up here: https://nam3forum.com/forums/filedata/fetch?id=78463.)

I do not think any post-foam mount failures have been reported.

However, the theory seems to be that foaming the mounts simply moves the failure points to the RACP-chassis attachment points - and that the RACP will eventually separate from the chassis. I could not find any convincing evidence that this happens with any regularity in the real world.

[pawelgawel]

As Poss explains in his response above, the structural foam does nothing to address the underlying design flaw. It’s simply a bandaid (similar to just welding on traditional plates) that addresses one of the symptoms of the design flaw.

Simply put, the RACP will still pull away from the rest of the chassis when foamed. So the lifespan of the foam really is not of any great significance.

The foam was a cheap way for BMW to push the problem in front of them long enough to get out of the class action lawsuit. Nothing more, nothing less.


Sent from my iPhone using Tapatalk

Mybe Im playing devil's advocate here, id like to see the extent of damage after plates are done and foam. I haven't been able to pull up any examples mysefd, maybe someone can post some links?

[heinzboehmer]

I have received my rivet/epoxy VinceBar and VinceSkinz. I am now gathering the rest of the parts to refresh the entire rear suspension while it is apart.

The previous owner did the BMW foam injection. How much trouble is the foam going to cause for me when installing the bar and skinz?

Jesse

Not much. Just don't light it on fire when cutting up the trunk floor.

[D-O]

I have received my rivet/epoxy VinceBar and VinceSkinz. I am now gathering the rest of the parts to refresh the entire rear suspension while it is apart.

The previous owner did the BMW foam injection. How much trouble is the foam going to cause for me when installing the bar and skinz?

Jesse

[poss]

I would like to see a solution that can be added without making such extreme modifications to the existing sheet metal, other than maybe a few drill holes. Is it possible?

You could try pumping epoxy foam into every cavity - but I wouldn't recommend it

I wouldn't class this as an extreme mod. It's less effort than doing the bottom-side reinforcement - you're only cutting away a strip of non-structural boot floor sheet metal to fit the bar in. If you use Vince's epoxy solution it only requires a few drill holes and rivets plus glue after that.

If you want the car to last this is a mandatory op unfortunately. As both Vince and CMP say, its not a matter of if but when...