E60: Horrible dash rattle - loose Strut Brace.

If there is a loud rattle from behind the dash on your E60, the sound of two plastic surfaces creaking against each other like tectonic-plates, or a cracking noise that sounds like the windscreen is flexing, then the strut-brace is loose. 

This is the alloy bar that bolts across the front suspension turrets and also to the firewall in the middle, which cuts down on chassis-flex as the front wheels move around. The E39 didn't have one and the E60 doesn't need one, but it's there and if one of the bolts come even slightly loose then it produces a rattle inside the dashboard like no other. It is not easily identifiable as a loose component in the engine-bay by ear as the noise is so internal and you may find yourself, as I did, spending forever adjusting panel fit inside the dashboard and cable-tying wire connectors with no joy. Rest assured it is a loose bolt on the strut-brace.

The problem is steel bolts going into alloy threads on the strut-tops, which become loose easier and are more prone to damage if overtightened or the strut-brace is removed and refitted a lot. BMW are aware of the problem and they're official fix is detailed in this PDF [http://5series.net/forums/attachments/e60-discussion-2/37844d1190387791-cracking-sound-e60-dashboard-sib_511304.pdf], but they will charge a premium for this and probably replace the brace.

The strut-brace attaches in three places, with two bolts in the centre joining the firewall and one either side on the strut-tops. They have E10 double-hex heads. Two of my four bolts were loose - one of the centre ones, which just kept spinning and needed coaxing out, and the O/S strut-top. This would get near tight then skip and go finger-loose again. The strut-brace was so loose this side that it could be moved around by hand at the end with the bolt in place.

Quick Repair Options:

• Heli-coil - This is the recommended or 'pro' way. You can get a hell-coil kit for £10-£20 and it basically winds a new stainless-steel thread into the old one so the original bolt tightens straight back in.
• Drill out and re-thread - This is cheaper and dirtier as it just involves boring out the hole with the damaged thread to a larger size and using a die to re-thread it to accept a larger bolt. This is what I did, drilling the offending hole in the O/S strut-top out to 9.5mm and threading it using an M10 tap. I then used a short M10 bolt (17mm) with a large knurled collar to keep that end of the brace nice and tight.

---

This did NOT fix the rattle?

If you're strut-brace is not loose and the noise is still there then it could be two other things:

• Axial tie-rod / Track-rod end failing - Yes, when the axial tie-rod / track-rod ends start to fail it does produce a rattling / cracking noise from behind the dash, just like a loose strut-brace. No one would ever guess this defect would make this sound where it occurs, but there you go. I suspect this was the cause of the rattle in my E60 after all, though never had chance to replace the part before I sold it and the guys buying it both agreed the noise was something steering-rack related. 
• Loose trim - If the sound is definitely originating behind the dash then loose trim or structure is likely your culprit, though this is quite rare. E60s use alloy design and the body absorbs a lot of flex, so when stuff behind the dash does become loose the sound is amplified in the cabin. I am sure when this does happen, every case is different so there is probably a lot written about it online. Best of luck tracking it down. 

---

This is a common fault and there is plenty of information on the forums:

http://5series.net/forums/e60-discussion-2/cracking-sound-e60-dashboard-45017/

http://www.bmw-driver.net/forum/showthread.php?t=44948

http://forum.bmw5.co.uk/topic/80790-a-slight-knocking-noise-from-the-dash/

http://forum.bmw5.co.uk/topic/17634-rattle-from-dash-on-start-up-from-cold/

E46 Clubsport: Nay's new wing! Paint, polishing... fail.

It's good to get the purple 330ci Clubsport on the pages of BeemerLab and a bit of bodywork, no less. The driver's side wing was a bit bubbly when he got the car and has worsened somewhat over winter - front wings are the classic rusting spot on E36 / E46 after all and no matter how well you patch it up, it always comes back before long, so Nathan went the whole hog and bought a new patterned wing for just under £100. Despite offers to have it sprayed professionally for next to nothing, he opted to do the work himself with a rattle can of Holt's Colour-Match, mixed at Halfords.

He started with U-Pol Hi-build filler primer to deal with imperfections in the etch-primer, moved on to a single can of Holt's 'BMW 576 Velvet Blue Metallic' and finished off with 2.5 cans of Halford's own clear-lacquer. A spray guy at work gave us a tip - apply the first coat of lacquer and wait a couple of minutes for it to go tacky but not start to dry, then apply a good thick second coat. This enables you to get a proper coat on that can then be layered on without causing crazing in the base lacquer. Nay tried this out and, after 4 more coats, some flatting back with 1800 Wet/Dry and a bit of machine-polishing, the finish is glass-like and the colour-depth superb. What a shame that, after a week spent carefully spraying one wing, the colour-match is terrible. I guess this is a lesson not to have complex paint codes mixed up at Halfords. A local painting firm is on the case, watch this space...

Only 330 M Clubsport models were built in the original three colours. Only about 40 were made in Velvet Blue. This is one of the 40 and it has seen better days. 

E60: Unbearable rattle with new Alpine install + shonky fix.

No sooner have I got the Alpine install sounding heavy in the E60, it shakes some trim loose and begins to cause the world's most annoying rattle. At first it was barely audible and only at high volume. Now it's all the time and louder than ever, all music and even low volume. 

It turned about to be the plastic trim-panel behind the centre arm-rest. I've stuck some foam-sponge into the gaps around it for now and hopefully this will help, but it will need something more like Dynamat at some point.

The low-end rumble produced by the E60s stock-subs, amplified again through the Alpines is shaking panels loose on a very well built car. There is a 22mm thick carpeted MDF panel behind the rear-seats that forms the back of the boot and the front-facing subs are driving straight into it, which already muffles the bass considerably and gives vibration in the cabin. I have read posts where large holes are cut into the MDF in front of each sub to get the bass through, but I can't see that helping vibration and and am reluctant to cut the panel yet. Turning the subs to face away from the rear-seats might help the vibration but I doubt it'll make the bass sound any cleaner and am loathe to expose the sub-cones to loose luggage and lose space by bringing the amp / x-over out onto the boot floor. Again, some sort of sound-matting such as Dynamat will need fitting around the boot and between the rear-seats and parcel-shelf to iron out the remaining hum. As for getting more bass through, the best quick advice would be to open or remove the 'ski-hatch' if your E60 has one, sadly mine does not.

The optimal settings I've got so far since taking RCA-feed from the stock-subs is to have the iDrive bass set to +3 or 4 and the X-over on less than a quarter gain, as the low-end frequencies are just so loud on the Alpines. The low-mid frequencies don't really get to the subs at all though and this where the stock-system needs to take over, but turning the bass over halfway on the iDrive is over-driving the subs and there's no choice but to keep turning down the x-over gain. Hopefully I can turn the x-over back up a bit again now the rattle is sorted.