Z3M boot floor

For the M Powered Z3 derivatives
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soma
Joined: Mon 14 May, 2007 12:14
Posts: 189

  M coupe S50

Post by soma »

HI Matt,
Looks like a very thorough job...and a great price too! Did you get the diff brackets reinforced as well?
1999 Cosmos Black MCoupe - 1 of only 27 original Australian imports
freelandm
Joined: Wed 16 Jan, 2008 09:42
Posts: 109

  M roadster S50
Location: Huddersfield

Post by freelandm »

Hi Soma

No mate, i did ask about the integrity of it and it didn't concern him. I think that the problem lies with the spot welds so that has been sorted/eradicated so i think the rest should take care of itself to be honest.

I will be keeping an eye on the repair but to be honest Lez knows his stuff and i trust him 110% on the repair he has made, how it should have been done properly in the first place.

Now i just wish summer was here to put it through its paces now i have confidence back in the car. Nothing worse than tottering about because you are worried about making it worse.

Kind Regards
Matt.
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soma
Joined: Mon 14 May, 2007 12:14
Posts: 189

  M coupe S50

Post by soma »

HI Matt,
Not to worry you mate but it is my understanding that simply repairing the spot welds only masks the visual damage. It is the Ms inferior diff bracket design that needs reinforcement to prevent the welds from popping in the first place. Perhaps someone can correct me here? :roll:
1999 Cosmos Black MCoupe - 1 of only 27 original Australian imports
corky
Joined: Fri 27 Nov, 2009 18:09
Posts: 265

  M roadster S50
Location: Wakefield

Post by corky »

soma.
Have you checked your welds in the boot
shantybeater
Joined: Wed 12 Mar, 2008 14:33
Posts: 1967

  Porsche
Location: UK

Post by shantybeater »

soma wrote:HI Matt,
Not to worry you mate but it is my understanding that simply repairing the spot welds only masks the visual damage. It is the Ms inferior diff bracket design that needs reinforcement to prevent the welds from popping in the first place. Perhaps someone can correct me here? :roll:
Yup you should really get the uprated diff bracket installed from BMW as well or go down a randy forbes route
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G2JRP
Joined: Fri 10 Apr, 2009 04:34
Posts: 454

  M roadster S50
Location: Dereham

Post by G2JRP »

I have just rung up about a m roadster which I am interested in buying and he had his boot floor done in 2004 as it was recalled by BMW. I dis not see the paper work but he had it all to hand. They wrote to him and the work was done.

Interesting I thought.
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shantybeater
Joined: Wed 12 Mar, 2008 14:33
Posts: 1967

  Porsche
Location: UK

Post by shantybeater »

It wasn't recalled so it was probably done free of charge as good will like mine and many others on the forum, BMW are pretty much out of generosity regarding this issue now as the cars are 10+ years old
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G2JRP
Joined: Fri 10 Apr, 2009 04:34
Posts: 454

  M roadster S50
Location: Dereham

Post by G2JRP »

He has the paperwork where BMW wrote to him to bring the car in to get the boot floor done, this was in 2004.
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shantybeater
Joined: Wed 12 Mar, 2008 14:33
Posts: 1967

  Porsche
Location: UK

Post by shantybeater »

Can you get him to scan this in and upload? if thats right it would be good ammo if you are looking for BMW to fix the car FOC
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freelandm
Joined: Wed 16 Jan, 2008 09:42
Posts: 109

  M roadster S50
Location: Huddersfield

Post by freelandm »

"Not to worry you mate but it is my understanding that simply repairing the spot welds only masks the visual damage"

The differential bracket was fine no problem with that. Maybe if i was goint to spank it around a track then i would have bought a coupe not a roady, to be honest i think the diff bracket will be fine.

Please explain masks the visual damage

Regards Matt.
shantybeater
Joined: Wed 12 Mar, 2008 14:33
Posts: 1967

  Porsche
Location: UK

Post by shantybeater »

From what i understand the spot welds are a side effect of the actual problem. Once the weak diff bracket starts to crack it pulls away at the boot floor leading to spot weld failure. So simply fixing the spotwelds is masking the main issue (being the diff bracket failure).

I dont think we are talking about spanking it around a track either, if its already started to go it will get weaker and weaker. Even some of the 1.9's have had diff bracket failure so having the level of torque from an M in comparison makes you realise it wont take an awful lot. (just my 2p) If i was you i'd consider ordering the uprated diff bracket supplied on the later Z's and get it fitted
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freelandm
Joined: Wed 16 Jan, 2008 09:42
Posts: 109

  M roadster S50
Location: Huddersfield

Post by freelandm »

No Diff bracket failure , just Spot welds that for 1 were not up to the job in the first place, so where you get this Diff bracket failure causing spot welds to fail is rubbish or else my Diff bracket should be shot.

Regards Matt
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Robin
Joined: Sun 14 Dec, 2003 18:35
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  M roadster S50
Location: Southampton
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Post by Robin »

Diff bracket thread here for anyone that may need to see it
http://www.zroadster.net/forum/viewtopic.php?t=20157
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soma
Joined: Mon 14 May, 2007 12:14
Posts: 189

  M coupe S50

Post by soma »

corky wrote:soma.
Have you checked your welds in the boot
Yes Corky...no problems thanks to this bit installed by the previous owner:
http://www.z3mcoupe.com/forum/showthread.php?t=10169
1999 Cosmos Black MCoupe - 1 of only 27 original Australian imports
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c_w
Joined: Thu 19 Aug, 2004 16:50
Posts: 4032

  M roadster S50

Post by c_w »

The diff bracket isn't the main fail point although it does happen, the main weakness is the spot welds of the crossmember to the bootfloor/chassis rails. The lack of spot welds around this area and directly above the bracket lead to generaly metal fatigue and eventual failure of the few spot welds that are there.
Desiro
Joined: Thu 31 Jul, 2008 15:59
Posts: 265

  M roadster S50
Location: Sheffield

Post by Desiro »

c_w wrote:The diff bracket isn't the main fail point although it does happen, the main weakness is the spot welds of the crossmember to the bootfloor/chassis rails. The lack of spot welds around this area and directly above the bracket lead to generaly metal fatigue and eventual failure of the few spot welds that are there.
So are you saying the repair that freelandm has had done is suffice, providing there is no damage to the diff bracket?
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c_w
Joined: Thu 19 Aug, 2004 16:50
Posts: 4032

  M roadster S50

Post by c_w »

Desiro wrote:
c_w wrote:The diff bracket isn't the main fail point although it does happen, the main weakness is the spot welds of the crossmember to the bootfloor/chassis rails. The lack of spot welds around this area and directly above the bracket lead to generaly metal fatigue and eventual failure of the few spot welds that are there.
So are you saying the repair that freelandm has had done is suffice, providing there is no damage to the diff bracket?
It certainly looks good and will probably be ok IMO as they are no longer spot welds in the BMW style! The bit that I would have done extra is added welds to the raised square section as seen in this picture;

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It does need flatting down a bit so that it can be welded to the cross memeber below. Directly below this is the diff mount, why it's not welded consistently across the boot floor I'm not sure but I reckon this contributes to some flex and the eventual failure of the spot welds.
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