Full 2006 Z4M Refurb & Some Questions Please

[jontZ4M]

Hi all I hope you are doing very well.

I've been completely inactive for the last 18+ months after having my first baby. Have barely touch Z4M since then other than idling it.

About two years ago I did a minor underside refurb on it. I promised that one day I'd come back and do a high detail full refurb removing all underside components. I've just started the refurb. If you are interested, I'll be updating this Facebook album as I go: https://www.facebook.com/media/set/?set=a.637453398797294&type=3

I've removed most of the suspension and have come across some problems. I have very little experience on BMWs and so a lot of the engineering is foreign to me.

Some questions I have already please:

1) the front lower wishbones - I've had to destroy the two rubber ball joint boots for each arm to get the arms off. Normally I would just replace the ball joints by pushing the old ones out and new ones in. However it appears that the ball joints are actually cast into the alloy and not removable? What is standard procedure here please?

2) the rear aspect of the front wishbones go into a rubber bushing, but I don't really understand how. It seems that a hexagon shaped piece of the wishbone is just pushed into the rubber of the bushing. Do I just pull/push it out?

3) I need to remove the hubs from the rear radial arms. I assumed that I would be able to push them out via a press but this is not possible due to geometry. What would be the best solution here? A normal type of hub/bearing puller?

4) I havn't tried removing the rubber bushings from the rear subframe or arms yet. Is there anything I should know about them? I assume that each bushing is surrounded by a metal ring and I also push that ring out with the rubber bushing?

5) on the rear radial arms, two of the bushings are strange, they project out of the are casting by about half an inch each side and they swivel, a bit like a rose joint. Anything I should know about removing/replacing these please?

6) this is a little way off but do we have a comprehensive set of torque settings for the various bolts for re-assembly?

That's it for now. Also if anyone has done this kind of thing before I really appreciate any heads up on other problems I'm likely to bump into. I've found it fairly tough going so far compared to cars I've worked on before.

Hugely appreciated as ever.

Jon

 

[ed80]

1) Wishbones on the E46 and similar models is disposable. You need a new wishbone, but luckily the Z4M shares a common part with the non-M E46, so they are not murderously expensive. Look for a Lemforder replacement, they are the OEMs so you get the exact part you would receive from a dealer. BMW part is here: https://www.sytnerstevenagebmwparts.co.uk/p/BMW_2007_Z4-M32-Coupe/Repair-kit--wishbone--left-VALUE-PARTS/132015001/31122341297.html

2) Yup, just push them out, swear a lot, and push some more.

3) Put a bearing separator behind the hub (don't tighten it, it's just there as a spacer), and you should be able to use a couple of wheel bolts through the hub to push against the bearing and push the hub out. If you have a slide hammer then that should work too. If you don't have either of these, then any bit of metal you can use behind the hub to push against will work.

4) The trailing arm bushes are not too bad, the subframe bushes are horrible. They both have metal rings you can use to press them out, bush removal tools for these cars are cheap as chips on ebay if you need one. Some people (cough, me) resort to fire or a sawzall (or both) to remove the subframe bushes

5) They are indeed rose joints. They push out the same as bushings, with this tool (or similar): https://www.ebay.co.uk/itm/334311631679

I think you covered most of the problems you are likely to run into. Sometimes bolts can seize into bearings (particularly the rear camber bolt) which makes life difficult. Most of the parts you will be replacing are OEM by Lemforder, and many are still available from EuroCarParts or similar.

You will be buying a LOT of nuts and bolts from BMW (a full set of hardwear for driveshafts alone is £180 :!, but this can be mitigated by buying from here: https://www.specialclassicparts.de/en/c/e46/suspension. They provide equivalent strength and spec, and look like they have better rust protection.

Lastly, there are a few videos by FCP euro that will help. They are E46 M3 specific, but 99% of the rear axle (and 80% of the front) is identical. Start here: https://www.youtube.com/watch?v=mKNPI5KTUK8

 

[ed80]

PS. Torque specs are here: https://drive.google.com/file/d/1GS3Hirx6x0c0WG8hPeXiwfXfeUldkQnm/view

 

[lucasxdiniz]

You will be buying a LOT of nuts and bolts from BMW (a full set of hardwear for driveshafts alone is £180 :!, but this can be mitigated by buying from here: https://www.specialclassicparts.de/en/c/e46/suspension. They provide equivalent strength and spec, and look like they have better rust protection.

I really don't want to take away from your excellent reply to the OP, but zinc plating is not better than the OE finish. BMW specs zinc flake (normally) which is a whole magnitude better than most zinc plated bolts. For zinc plating you can realistically expect ~48hrs salt spray before seeing red rust and only 8hrs before zinc corrosion appears (ISO 2081), whereas the OE finish is ~600hrs to red rust or 120hrs for zinc corrosion.

This is the reason why I take the hit on buying BMW OE bolts... It's tempting to just get everything zinc coated in a batch for £60-80, but most places dealing with such quantities will not care about heat treating 10.9 or above graded bolts to get rid of hydrogen embrittlement.

OP, beware that the Z4M uses the big case diff which require 12.9 hardware torqued to 100Nm. You'll struggle putting 100Nm through a hex drive!

 

[ed80]

That's interesting. I assumed the better corrosion protection because BMW bolts seem to rust almost instantly, and because Redish yellow passivate all the bolts when they do their £20k+ underside restorations:
https://www.youtube.com/watch?v=7ZY-pORsDYE&t=5352s

I ordered the diff plate and driveshaft bolts and they should be delivered on Monday, I will report back on how I get on.

 

[lucasxdiniz]

That's interesting. I assumed the better corrosion protection because BMW bolts seem to rust almost instantly, and because Redish yellow passivate all the bolts when they do their £20k+ underside restorations:
https://www.youtube.com/watch?v=7ZY-pORsDYE&t=5352s

I ordered the diff plate and driveshaft bolts and they should be delivered on Monday, I will report back on how I get on.

Passivated will certainly prolong the corrosion resistance. If you trust your platers to do the right treatment after plating, then it's the most cost effective solution (makes sense for a business).

From experience, I disagree. I've looked under my car after renovating the diff and many other items and bolts in the rear last winter and all the BMW hardware is still looking brand new. All the zinc plated stuff I put on has some corrosion showing where tools were in contact with them.

Good luck!

 

[maupineda]

If the ball joints in the FCA are good you can just replace the boot.

https://nam3forum.com/forums/forum/main-forum/e46-2001-2006/271090-front-control-arm-ball-joint-boot-repair

 

[jontZ4M]

That's amazing guys, thanks for the posts, especially Ed.

I'll start actioning all of your advice now.

Jon

 

[Simon 3.2M]

I would double check that the M wishbones are the same as the non M E46 ones, o thought they were M specific.

 

[ed80]

I would double check that the M wishbones are the same as the non M E46 ones, o thought they were M specific.

The M3 has model specific wishbones, the Z4M just uses boggo E46 M sport wishbones: https://www.realoem.com/bmw/enUS/part?id=DU92-EUR-11-2006-E86-BMW-Z4_M32&mg=31&sg=05&diagId=31_0779&q=31122341297

 

[InterlagosMC]

Z4m uses different front wishbones to e46 M3 due to front hubs being very similar to e36 instead of e46, same reason Z4M can’t use the BBKs available to the e46 M3

 

[ed80]

Z4m uses different front wishbones to e46 M3 due to front hubs being very similar to e36 instead of e46, same reason Z4M can’t use the BBKs available to the e46 M3

The kingpin is unique to the Z4M, but all the braking components (discs, calipers, brackets, pads) are the same as used on the M3 CSL. As far as I know, any brake kit that fits the M3 will fit the Z4M (wheels permitting). Would be interested to hear if there are any that definitely don't fit.

 

[InterlagosMC]

Due to the hub design the track rod knuckle is closer to the disc than the e46 m3 so we are unable to run the e92 m3 disc upgrade or the f80 m3 disc upgrade as those discs sit further back and contact the knuckle relative to the front face of the hub. I found all this out when I was looking for a reasonable brake upgrade for my M last year and unless you go AP Racing or Brembo at great expense they don’t have many options

 

[jontZ4M]

^^ Roger that guys, can confirm that I did order Z4M specific front wishbones.

I've ordered a whole load of stuff. Feels like half of the car. 24 packages arriving next week.

I plan to compare all parts to the originals thoroughly before use to ensure I've got the correct parts.

The only thing that worries me is the various bushings I've ordered, I found ordering the correct bushings surprisingly difficult and am slightly worried, BUT at the end of the day when I remove the old ones I'll caliper them and compare measurements to make sure.

FYI - updating the build thread linked in first post. Nothing hugely exciting at the moment.

 

[jontZ4M]

Hey guys - I pretty much finished the strip down today (currently just one day per week sadly, so takes a while).

Some questions:

1) in each wheel arch is a plastic doored black box which protects the wire plugs. How on earth do we remove these boxes?


2) Here is a pic of 3 types of fittings. The left one are the things that fix the heat shields. Middle is 8mm hex head screw(not bolt) that fix the wheel arch splash guards to nylon receivers. Right is plastic two-piece fixings that hold front arch splash guards to front bumper. Some of these are rusted or damaged and are not serviceable. Does anyone know where to get new ones or a suitable replacement?


3) I noticed an oil leak on front right of engine. Trying to figure out where it's coming from. I think there is oil in the the area I've highlighted in red box, do we think this means it's a cam cover seal? Not worked on S54 engine properly yet.


4) not a question but I noticed above ^^ you guys talking about replacing all bolts. That would be nice in a perfect work, but I'm hugely time-restricted on this and I think I'm only going to replace bolts I consider un-serviceable or really on their way out. To save faff.

Thanks a lot!

 

[ed80]

Can't help with 1 or 3, but for 2 you can find most of these at https://vehicleclips.co.uk/collections/bmw-z4-fixings-trim-clips-and-fasteners-e85-e86-2002-2008

The 8mm screws can be found on eBay (search for "e46 undertray screws") or at your local BMW dealer

 

[jontZ4M]

Guys I have some issues with new components that have arrived, can you please advise?



The yellow parts are at the rear of the front lower wishbones. With the originals from my Z4M the hole in the bushing is heavily offset (maybe 15mm off centre), but these replacements are only about 5mm off centre. Does anyone know what's going on here?

The red bush was supposed to be the one at the front of the rear radial arm, but has turned out to be a subframe bush. Anyone know the name of or how to find the bushing that fits are the front of the rear radial arms please?

Can't help with 1 or 3, but for 2 you can find most of these at https://vehicleclips.co.uk/collections/bmw-z4-fixings-trim-clips-and-fasteners-e85-e86-2002-2008

The 8mm screws can be found on eBay (search for "e46 undertray screws") or at your local BMW dealer

Thanks

 

[InterlagosMC]

Guys I have some issues with new components that have arrived, can you please advise?



The yellow parts are at the rear of the front lower wishbones. With the originals from my Z4M the hole in the bushing is heavily offset (maybe 15mm off centre), but these replacements are only about 5mm off centre. Does anyone know what's going on here?

The red bush was supposed to be the one at the front of the rear radial arm, but has turned out to be a subframe bush. Anyone know the name of or how to find the bushing that fits are the front of the rear radial arms please?

Can't help with 1 or 3, but for 2 you can find most of these at https://vehicleclips.co.uk/collections/bmw-z4-fixings-trim-clips-and-fasteners-e85-e86-2002-2008

The 8mm screws can be found on eBay (search for "e46 undertray screws") or at your local BMW dealer

Thanks

The e46 uses centred bushes for the front wishbone rear bush but the Z4M uses the offset bush for more caster angle, it’s also a popular upgrade for the e46 m3 owners to do.

The rtab should be oem number 33 32 6770817 for the z4m

 

[jontZ4M]

The e46 uses centred bushes for the front wishbone rear bush but the Z4M uses the offset bush for more caster angle, it’s also a popular upgrade for the e46 m3 owners to do.

The rtab should be oem number 33 32 6770817 for the z4m

Thanks. Do you think using the centered bushes on a Z4M will be a problem? Not sure how critical caster is.

 

[PDJ]

Thanks. Do you think using the centered bushes on a Z4M will be a problem? Not sure how critical caster is.

BMW considered it as they made off entered ones just for the Z4M you can keep the alloy boss and press out the robber and fit polly bushes that's what I did but with the originals