Elms subframe crack

[Neil M]

I recently posted on then other thread (Technical Area) regarding a BMW internal memo that I found in my history file. Some of you lads will now be familiar with it, having asked for a copy.

What I did find surprising when I sat down and took the time to read it, was the date the document was first circulated: 12/03 which is easily overlooked.
BMW knew about the likelihood of this defect occurring, as the CSL's were coming off the production line. (July 03 - December 03)

That being the case, this must have shown up during testing/proofing of the car, which was supposedly carried out at the Nurburgring.
BMW obviously found that the chassis couldn't cope with high degrees of lateral torsional stress/stain as in high speed cornering.

Good will gesture, or complete recall - no contest.
Not good for their image as the CSL was promoted as a race car for the road. I'm more inclined to think it's more a get out of jail free card.

This fault applies to all of the E46 model range, however as the CSL was marketed it will be predisposed to this fault occurring much sooner than on other models.
Bottom line: It is an inherent design defect.

[dave wilkinson]

[QUOTE=portlandgrey;n429652]I've read that the replacement floor is modified for greater support. After fitting, its then resin injected.

BMW have looked at the problem & provided an expensive, labour intensive fix - given the repair is 40 odd hours in labour alone.
If it was possible to sort the issue with a localised repair, costing far less, then i'm sure that BMW would have done it- they are footing the bill after all.


this^^^
the new boot floor is stronger as have different part numbers and slightly different design. i've seen it with my own eyes. for bmw to admit this tho will mean there admitting there's a fault and would have to recall all e46 m3's.

Mprove & Reddish repairs are not ideal if you ask me. they basically drill the end of the crack (to stop it sprending). then glue a plate over the top. nothing to stop cracks appearing from other spot welds. although the plates do help spead the load. for me personally i would'nt touch a csl thats not been repaired by a dealer as 'I' see the reddish repair as a bodge!

[mattCSLnut]

I've read that the replacement floor is modified for greater support. After fitting, its then resin injected.

BMW have looked at the problem & provided an expensive, labour intensive fix - given the repair is 40 odd hours in labour alone.
If it was possible to sort the issue with a localised repair, costing far less, then i'm sure that BMW would have done it- they are footing the bill after all.

If for any reason BMW reject a repair claim, then you've go Mprove & Reddish offering the localised welding/plate fix at a more wallet friendly price.

I don't know where U've read that... unfortunately it's incorrect.
Despite the replacement boot floor having a different part number, it is still the same steel boot floor as the original. The improvements come with the injection of structural foam into the void between inner & outer boot floor that's part of the Official BMW repair which stops any flexing at the rear that's responsible for the chassis cracks developing in the first place. This is why BMW offer this foam injection solution, if they find no chassis cracks. No flex = No cracks.
This information has been provided & confirmed by Emma & Gareth @ Elms Camborne + Malcom (the body shop estimator form Elms Stansted, where the actual chassis repair are undertaken.

[dave wilkinson]

I don't know where U've read that... unfortunately it's incorrect.
Despite the replacement boot floor having a different part number, it is still the same steel boot floor as the original. The improvements come with the injection of structural foam into the void between inner & outer boot floor that's part of the Official BMW repair which stops any flexing at the rear that's responsible for the chassis cracks developing in the first place. This is why BMW offer this foam injection solution, if they find no chassis cracks. No flex = No cracks.
This information has been provided & confirmed by Emma & Gareth @ Elms Camborne + Malcom (the body shop estimator form Elms Stansted, where the actual chassis repair are undertaken.

like i've just said matt-

the new boot floor is stronger as have different part numbers and slightly different design. i've seen it with my own eyes. for bmw to admit this tho will mean there admitting there's a fault and would have to recall all e46 m3's.

the foam injection is NOT i cue is a prevention! there's a few e46's out there that have had the injection and still cracked later on. :beer:

[Steve B]

The other issue is if you have the foam injection you can't have the repair kit done it has to be a full panel replaced. I was told this by Redish when I enquired about the repair panels.


Steve

[mattCSLnut]

like i've just said matt-

the new boot floor is stronger as have different part numbers and slightly different design. i've seen it with my own eyes. for bmw to admit this tho will mean there admitting there's a fault and would have to recall all e46 m3's.

the foam injection is NOT i cue is a prevention! there's a few e46's out there that have had the injection and still cracked later on. :beer:

Are you suggesting the guys @ Elms are spreading misinformation ?
Highly unlikely as Elms are the busiest and most experienced BMW main dealer doing this repair at the moment.
Just because a BMW car part has a different part number doesn't mean it's different, improved or otherwise.
Most car manufacturers (BMW included) change/supersede part numbers over the years. It's a common practice.
Maybe just maybe BMW are using a slightly thicker gauge steel for the replacement boot panels, the press pattern has to be the same to fit the rest of the old E46 chassis.

[dave wilkinson]

Are you suggesting the guys @ Elms are spreading misinformation ?
Highly unlikely as Elms are the busiest and most experienced BMW main dealer doing this repair at the moment.
Just because a BMW car part has a different part number doesn't mean it's different, improved or otherwise.
Most car manufacturers (BMW included) change/supersede part numbers over the years. It's a common practice.
Maybe just maybe BMW are using a slightly thicker gauge steel for the replacement boot panels, the press pattern has to be the same to fit the rest of the old E46 chassis.

so maybe it is different

no i'm not suggesting elms are spreading misinformation, like i say bmw cannot say its different as that would mean there admitting a fault, and involve a recall, costing alot more. when i say bmw, i'm meaning bmw uk not the dealers.

[Straightsix]

I recently posted on then other thread (Technical Area) regarding a BMW internal memo that I found in my history file. Some of you lads will now be familiar with it, having asked for a copy.

What I did find surprising when I sat down and took the time to read it, was the date the document was first circulated: 12/03 which is easily overlooked.
BMW knew about the likelihood of this defect occurring, as the CSL's were coming off the production line. (July 03 - December 03)

That being the case, this must have shown up during testing/proofing of the car, which was supposedly carried out at the Nurburgring.
BMW obviously found that the chassis couldn't cope with high degrees of lateral torsional stress/stain as in high speed cornering.

Good will gesture, or complete recall - no contest.
Not good for their image as the CSL was promoted as a race car for the road. I'm more inclined to think it's more a get out of jail free card.

This fault applies to all of the E46 model range, however as the CSL was marketed it will be predisposed to this fault occurring much sooner than on other models.
Bottom line: It is an inherent design defect.

Hi mate as far as I am aware this happens to all E46s. This happened to my 2000 323Ci Coupe which had the rear subframe axle carrier done by BMW UK in 2007. I noticed some odd noises after doing a Car Control course with the 323Ci at Bruntingthorpe and u could feel a slight vibration. In the early days was thought just to affect E46 323/328 which is what was said in a BMW Car Magazine E46 3 Series Coupe buyer guide

[shimmy]

I've also read here that the new floor has ridges and a slight reinforcement improvement. Someone posted picture of it a year or so ago.

[Steve B]

I had mine done at Specialist Cars body shop in Hitchin by someone I went to school with (he's been there for 24 years and served his apprentiship there and never left).... He told me that he'd done over 50 and this was 5 months ago..


Steve

[shimmy]

I had mine done at Specialist Cars body shop in Hitchin by someone I went to school with (he's been there for 24 years and served his apprentiship there and never left).... He told me that he'd done over 50 and this was 5 months ago..


Steve

Wayne?

[Steve B]

Ray Brookes