Subframe Reinforcement

[BavarianZHP]

This is a known issue... But how many of you have dealt with it? How many have you chosen to reinforce the subframe with welds?

I'm worried about mine even though it's fine (inspected 6 months ago). Should I invest in some reinforcement plates? I don't push the car hard, but I am planning on keeping her for a long haul. This rear subframe issue is the most worrisome for me, mainly since it's not like a simple job like the other preventative maintenance ones if something does fail...

[Vas]

It on my bucket list.

[derbo]

I dealt with it from a preventative standpoint with BMW structural foam injection.

BMW 83190445721 foam really is a Henkel Terocore 1401.

I hate to post a link outside here but this is a good description on what was done.
http://forum.e46fanatics.com/showthread.php?t=939044

[danewilson77]

I dealt with it from a preventative standpoint with BMW structural foam injection.

BMW 83190445721 foam really is a Henkel Terocore 1401.

I hate to post a link outside here but this is a good description on what was done.
http://forum.e46fanatics.com/showthread.php?t=939044

It's all good. Cross pollination of knowledge is encouraged.

HTC DNA, Williamsburg, VA

[derbo]

There is another option of epoxying the reinforcements as well. That can also be another option if you don't want to weld.

I think the structural foam is the best bet.

[BavarianZHP]

I'm assuming the foam method is much easier on the wallet as well. If I do this, that looks like the route I'll be taking.

[derbo]

I'm assuming the foam method is much easier on the wallet as well. If I do this, that looks like the route I'll be taking.

I remember the foam being around $100 or so each.

You need the tool that can does double caulking as well.

SIB INFO
Latest SIB for subframe foam FIX
- Update FEB 2009 SIB 41 04 08 (not available in TIS)

Note on repair
- Crack must not exceed 20MM for the Foam repair
Quote
"The following Procedure apply only to cracks at or around the left rear mounting point for the rear axle carrier"

Parts needed
83190445721 - Structural foam pack (includes 2 cartridge pack, enough for one vehicle)
51711906001 - Body Plug - 10mm
07147127539 - Body Plug - 12mm
Locally sourced - 3/8" clear plastic tube ( approx 10" needed)
Art #08901003 - Wurth AdhesiveFlex Seam Sealer ( For more info refer www.wurthusa.com)

The recommended applicator for the structural foam is the MIXPAC pneumatic applicator; model number DP400-85-01. This applicator may be contained from Conveniently Packaged Adhesives (CPA) : website : www.forcpa.com

[derbo]

http://www.m3forum.net/m3forum//showthread.php?t=401979



edit:

best DIY imo for this

http://www.m3forum.net/m3forum/showthread.php?t=421501

[QC_ZHP]

Great info derbo, I'll be looking into this soon

[derbo]

Hope this works.

IMO is the best if you can find the stuff. I barely could get two from my own dealership when I worked there.

[cakM3]

I may opt to do the rear subframe reinforcement for the ///M just to be on the safe side.....

[LivesNearCostco]

Is it possible to do both foam and plates, and if yes, do you have to weld on the plates first because welding will cause the foam to burn if you do the structural foam first? I suppose I could do the foam myself and later pay a shop to drop the subframe, epoxy on the plates, and replace my subframe bushings.

[derbo]

Is it possible to do both foam and plates, and if yes, do you have to weld on the plates first because welding will cause the foam to burn if you do the structural foam first? I suppose I could do the foam myself and later pay a shop to drop the subframe, epoxy on the plates, and replace my subframe bushings.

Definitely do the welding first then foam. Or epoxy the reinforcement whenever before or after the foam.

[BavarianZHP]

Awesome advise Derbo. This is definitely on my to-do list... Now we all know who to contact for any assistance!

[derbo]

I never did the subframe reinforcement beyond the foam method.

[Vas]

I would do the foam but ideally a kit from a place like turner is the best imo.

[SoCalZman]

How many ZHPs have had subframe failure? Anyone on this board?

[BavarianZHP]

How many ZHPs have had subframe failure? Anyone on this board?

Would love to know this as well... Would like to know driving style and miles too.

Me:

2003 ZHP 6MT sedan. Casual Driver. 67k miles. No subframe issues (inspected by shop).

[LivesNearCostco]

I have a crack in my rear floor pan. It's not right where the subframe bolts are. My mechanic spotted it. It's not that big but it is there. I'll need to get it welded up one of these days. At that time not sure if I will have reinforcement plates welded on or epoxied on. I might even have the plates put on by the shop then later inject the foam myself.

Somebody on m3forum.net had a photo that looked exactly like my floor pan crack. I'll try to find it and post a link later.

[danewilson77]

How many ZHPs have had subframe failure? Anyone on this board?

None that I've heard of.

HTC DNA, Williamsburg, VA

[derbo]

Its been known the most common ones that break are the pre-LCI cars and the E46 M3s. However it definitely doesn't exclude our cars from being potentially damaged. I myself haven't seen any later models get damaged like this beyond the 2003 model. But it doesn't mean it can't happen. :(

[LivesNearCostco]

Here's a photo of somebody else's rear subframe mounting area crack that looks similar to mine. Not sure if mine is in the same place, but it looks something like this, only harder to see because of the undercoating.
http://i1206.photobucket.com/albums/bb444/FrankieJones5/M3/15fddbc3825a51565d452aadc845c3f2.jpg

[DSC-off]

Here's some cracks found on my M3's subframe, had to strip off the undercoat to really see it. They were by no means bad, but clearly some force is being concentrated here.
9621
9622

[JeffSaysThings]

I'm bumping a 2 year old thread, but here goes...

ECS is selling the "structural foam" reinforcement kits right now for a pretty good price. They're about $85 per cartridge I think. I bought two sets and did the installation this weekend. It's remarkably easy to do! I figure it's good preventative maintenance and it should help the chassis get through 150k+ without any problems.

Calling it foam is a stretch though... the stuff does expand a little while it cures, but the final product is pretty hard and dense. As a structural engineer I'm honestly pretty impressed by the concept... as long as it works!

I found several good DIY threads on E46F so I didn't bother making another. However I did buy a big double-barreled caulking gun for the job (worked perfectly!) and I don't need it anymore. If anyone wants to undertake a subframe reinforcement, I'd happily pass the tool along for a low price.

[ELCID86]

^engineer approved! :thumbsup
Thanks for the review.


Thumbs, iPhone, TaT.

[danewilson77]

Did you take any pics? Thanks for the review.

Sent from my SM-G925V using Tapatalk

[slater]

I'm bumping a 2 year old thread, but here goes...

ECS is selling the "structural foam" reinforcement kits right now for a pretty good price. They're about $85 per cartridge I think. I bought two sets and did the installation this weekend. It's remarkably easy to do! I figure it's good preventative maintenance and it should help the chassis get through 150k+ without any problems.

Calling it foam is a stretch though... the stuff does expand a little while it cures, but the final product is pretty hard and dense. As a structural engineer I'm honestly pretty impressed by the concept... as long as it works!

I found several good DIY threads on E46F so I didn't bother making another. However I did buy a big double-barreled caulking gun for the job (worked perfectly!) and I don't need it anymore. If anyone wants to undertake a subframe reinforcement, I'd happily pass the tool along for a low price.

nice, thanks. i'm not a structural engineer, but have done a lot of research of the rear floor and the failures that occur, and the BMW-approved solution of filling that cavity makes the most sense to me as well.

when you say you bought 'two sets', do you mean 4 cartridges? or 2 cartridges?

did you just fill the two rear mounts, or all 4? there seems to be some controversy over whether the fronts are necessary, however i think they are - "while you're in there", you might as well. cheap insurance. i'm filling mine shortly.

peter

[Vas]

So this is the item. http://www.ecstuning.com/BMW-E46-330i-M54_3.0L/ES1898189/

How many are needed per vehicle?

[yura]

I know a local shop in Vancouver does a lot of plate-weld installations on M3s. Have also seen people use the foam. If I had an M3, I would do both methods just to be safe. I don't think there is much potential for this issue to develop on ZHPs, though.

[JeffSaysThings]

Well, each cartridge contains 2 tubes of goop, but you can't detach them or use them separately so I figure the two attached tubes makes for 1 cartridge of epoxy. I bought two cartridges (so $160 total). The BMW service letter says to use one for each side. They also recommend just reinforcing the rear mounts. The left rear appears to be the most critical one, so if you're going to do something, I'd start there. Like I said though, I did both sides. I didn't see any way to get to the front mounts so those were left alone.

I didn't take any pictures, but my procedure followed the link below. Just pretend those pictures are mine... except my car is red. :)

http://www.m3forum.net/m3forum/showthread.php?t=421501


I'll also add, I wouldn't do the plates on a ZHP unless I already had a crack or I was gonna drop the subframe for some reason. Dropping the subframe looks like a pain in the nuts so it's not something I want unless it's getting serious.

[slater]

Well, each cartridge contains 2 tubes of goop, but you can't detach them or use them separately so I figure the two attached tubes makes for 1 cartridge of epoxy. I bought two cartridges (so $160 total). The BMW service letter says to use one for each side. They also recommend just reinforcing the rear mounts. The left rear appears to be the most critical one, so if you're going to do something, I'd start there. Like I said though, I did both sides. I didn't see any way to get to the front mounts so those were left alone.

I didn't take any pictures, but my procedure followed the link below. Just pretend those pictures are mine... except my car is red. :)

http://www.m3forum.net/m3forum/showthread.php?t=421501


I'll also add, I wouldn't do the plates on a ZHP unless I already had a crack or I was gonna drop the subframe for some reason. Dropping the subframe looks like a pain in the nuts so it's not something I want unless it's getting serious.

there is a way to get to the fronts - remove the rear seat, and you can inject through one of the seat belt anchor points. i have diagrams of the cavity somewhere, i should dig them up and post them...

in my opinion, dropping the subframe - and installing flat-faced subframe mounts (a la AKG polyurethane mounts) - should be something you do along with filling the floor cavities. it should not affect ride quality, although it will definitely improve handling and 'feel'.

peter

[dpark]

Bumping an old thread. Did any ZHP owners ever have the subframe failure? Mine was inspected by the dealer in July 2010 and no problems were found.

Just curious if it didn't show in 2010, is it something to worry about xx years down the road?

[sillieidiot]

Bumping an old thread. Did any ZHP owners ever have the subframe failure? Mine was inspected by the dealer in July 2010 and no problems were found.

Just curious if it didn't show in 2010, is it something to worry about xx years down the road?

Yes there are some people. Most people don't even check so it's hard to tell. But it happens on all years. It's a definite that it will crack, it's just a matter of when.

[cornercarver]

Curious if there have been any reported problems relative to the structural foam. One potential issue I see; you can't weld the subframe area once you've 'foamed' it. Presumably the stuff is flammable and/or will degrade if you ever try to weld the metal to which it is adhered, and there's no way to remove it once it's in.

[dpark]

Yes there are some people. Most people don't even check so it's hard to tell. But it happens on all years. It's a definite that it will crack, it's just a matter of when.

So, if I understand the gist of the thread, if it wasn't cracked when they did the inspection (and repaired it), if the subframe cracks down the road, for the original owner, will have to be covered by the owner?

BMW won't pay anything at this point in time, assuming that you are right, and that the subframe failure is a "when" not "if" issue?

[Sockethead]

That is correct. That campaign is over

[BMWM3186]

The only time I've heard of a post 2002 car with a cracked subframe it was when I stumbled upon a 2003 Zhp for sale with like 250k miles. I'm not really going to worry about it too much on mine.

[slater]

Yes there are some people. Most people don't even check so it's hard to tell. But it happens on all years. It's a definite that it will crack, it's just a matter of when.

+1. it's a design flaw. it WILL crack. then the rear floor will start to separate from the unibody.



So, if I understand the gist of the thread, if it wasn't cracked when they did the inspection (and repaired it), if the subframe cracks down the road, for the original owner, will have to be covered by the owner?

BMW won't pay anything at this point in time, assuming that you are right, and that the subframe failure is a "when" not "if" issue?

let's get something straight first - it's not a problem with the SUBFRAME. it's a problem with the RACP (Rear Axle Carrier Panel - aka, the rear floor of the car). the subframe is mounted to the RACP, and not to the frame rails, like it should have been. it's too much load for the RACP, and the sheet metal is quite thin.

the post-10/2004 3-series cars had a 'reinforcement' piece sandwiched into the rear floor cavity, which should help prevent flexing of the RACP - however, ift is my opinion that even those cars can still crack in the normal first cracking spot (at the kink in the floor by the left rear mount), but they will do so much later.