My E46 M3

[brettski]

Hi guys i bought this last year and thought i would try and do a journal for a change. The car is a 2002 in Carbon Black with Imola red leather and as far as i'm aware it has every option except the rear blind and sunroof.



It has a full service history but i wanted to have an Inspection 2 carried out and to have it all checked over. I went to BMW and bought some parts including new badges and side indicators and gave it to Danthe to work his magic on the car.





Dan found a few issues these included the power steering pipes were leaking slightly so he managed to make some for a lot cheaper than BMW which i now believe are available. You can check out his Facebook page which is BM Conversions uk ltd. The sump plate also had some damage.







I asked Dan to check out the subframe even though a BMW Specialist in Manchester had given it the all clear a couple of months previously but he managed to find some cracks. After getting some cash together i've given the car back to Dan which has now resulted in this.









Dan is reinforcing all of the rear end seam welding it properly like a race car rather than buying the Redish plates. Dan didn't think much of the plates or the foam that BMW approve of! Here are some more pics.







Boot floor cut out



Reinforcement going in!


[URL=http://s1287.photobucket.com/user/d18re ... t.jpg.html]









Everything at the rear is being undersealed, replaced and powder coated including new rear shocks, Discs, pads, bearings and bushes etc.


I'll update once the car starts coming together

Cheers

[maxfield]

I still really fancy an E46 M3, carbon black with the red interior is my favourite colour combo.

Will be keeping an eye on this thread

[schoonerm3]

Thats the way to reinforce these cars!! Gad to see others realizing this As plates are not enough alone and exposy injection is a pile of codswallop.. And is exactly how I did mine last summer.

Did you get the hardware custom made or did you purchase the hardware from the guy that designed the method? I found it cheaper to buy it off the guy that created the idea.

This is mine. Front was done the same also.

[DanThe]

The plates are a waste of time IMO, just like putting a plaster over the problem that is bound to come back. I got a local machinist to make the longer bolts, cost about £40 IIRC

Best way to do it though, you know for sure its never going to be an issue again, and the floor is nice and original underneath too

[schoonerm3]

Wow that's cheap! I wanted a special material for my bolts but it was way more to manufacture. Think I paid 130 euro for my hardware.

The job you did on the upper portion of the front mounts is very tidy. The gussets are very neat.

I assume you welded the cracks on the floor itself, that front mount is significantly cracked on the floor area and would warrant a plate in my opinion because that steel is extremely weak aftet the cracking and flexing, there is an internal structure that relies on the outer cracked skin for support and is spot welded to it, and that's why I would have plated it in conjunction with the brace.

I outlined in blue the rough area that has that internal base plate of the threaded anchor.
And you can see it better in he second pic.
URL=http://s1104.photobucket.com/user/schoo ... j.jpg.html][/URL]



I put plates on mine as well because I figured there is nothing to lose as they will have some benefit. But on their own they are not enough I 100% agree and don't get the started on the epoxy resin. Lol

Have you any pics of how you put the boot skin back on? I still haven't put it back. Is there much playing around?

[Andyboy]

The plates are a waste of time IMO, just like putting a plaster over the problem that is bound to come back. I got a local machinist to make the longer bolts, cost about £40 IIRC

Best way to do it though, you know for sure its never going to be an issue again, and the floor is nice and original underneath too

+1000.

Great to see these being fixed properly as the plates are just a waste of time. My 323i cracked on the rear passenger side so a mate did a quick economy repair (V reg 323i.....) - cut the upper boot floor open from inside the boot, weld up the cracks and failed spot welds. Then wind the bolt all the way in, weld another plate on top with both seam welding around the edges and 4 or 5 plug welds around the bolt before zipping the upper boot floor shut again.. Really, the lower skin that everyone gets worked up about is a covering panel and doesn't do that much.

[schoonerm3]

The plates are a waste of time IMO, just like putting a plaster over the problem that is bound to come back. I got a local machinist to make the longer bolts, cost about £40 IIRC

Best way to do it though, you know for sure its never going to be an issue again, and the floor is nice and original underneath too

+1000.

Great to see these being fixed properly as the plates are just a waste of time. My 323i cracked on the rear passenger side so a mate did a quick economy repair (V reg 323i.....) - cut the upper boot floor open from inside the boot, weld up the cracks and failed spot welds. Then wind the bolt all the way in, weld another plate on top with both seam welding around the edges and 4 or 5 plug welds around the bolt before zipping the upper boot floor shut again.. Really, the lower skin that everyone gets worked up about is a covering panel and doesn't do that much.

The top portion of the all 4 mounts must be addressed for sure. The cracks we see on the lower skin are secondary to whats happening on the upper portion. Thats the beauty of the bolt through method as it has such brilliant load relief properties that plates cannot achieve.

But in saying that, plates have their place also when a floor has suffered cracks and has endured the flexion over the past 10-15yrs. The metal will have fatigued and as I showed above the lower skin does have an important role that should be treated if it has failed previously. I epoxied plates on just to put some strength back into the lower skin aswell as the above method.

Carefully placed extra plug welds to tie the lower skin back into the internal structures ( You must know where it is) is a good idea also such as below you can see where I added extra plug welds on the left rear mount. Idea is to relieve existing spot welds that have been weakened.



Looking forward to seeing the updates OP. Sorry for cluttering your thread I just love this topic

[DanThe]

There are a couple of reasons I wouldn't weld plates on the underside, firstly it looks horrible, even with a gallon of spray on bullshit sealer spread around and some new paint and/or underseal.

But mainly, by doing this you are also altering the way the suspension works because the pivot points are being moved, its only a couple of mm's but it all makes a difference.

The reason the body cracks at the front mount is because the rear drops and the long bolt at the front twists the threaded mount with every on/off throttle, as we know if you twist steel back and forth enough times it will crack. I hit the cracks with a disc cutter/carbide burr/drill and welded them all up then linished back to the the original panel height. It won't crack again because the floor will no longer be pulled down at the back

[schoonerm3]

The change in pivot point is a good point. I did think about that but decided it wouldn't affect to much , would love to know exactly how much it effects it though. My plates are epoxied on so could always hack them off haha.

There are many theories about why the front mounts crack. I do like yours however..

Other theories are that the upper spring perches ( upper control arm) create a powerful leveraging force on the front mount's pulling them downwards . This makes sense if you consider the strength in the coil and the weight of the car all of which together are creating a downward lever on the front mounting points because the inner spring perch connection to the subframe is much closer to the front mounts than to the rear mounts.

There is a hypothesis that true rear coilovers would help tremendously because they remove the stock rear coil and relocate it. But this leads to reinforcement of the strut tower

Another one is that the OEM MIG welds in the upper portion of the front mount just cracks as it is apparently the first point fail according to Redish. Maybe it cracks because the panel just can't cope with the original method of load relief which is down to poor design.

No matter what. This method is the most bulletproof method to hit the streets. Ideal for a road car. After this the next option would be a full diff pickup cage of some sort .

I would like to see more people take this issue more seriously. To many people especially on m3cutters are let into a false sense of security that plates is a sufficient fix.

[ross_jsy]

Sorry am I reading that right, BMW approve an epoxy resin repair?

[DanThe]

Yes Ross, drill some holes and bang some 2 pack resin in, that'll fix it! £650 + VAT for your authorised 'repair' please sir

[ross_jsy]

I'm shocked that that is a BMW approved repair

[Adilm3]

I think this is what i need done on mine too.

[retroboyo]

Interesting thread. What make the bolts needing to be longer please