Subframe refurb on my 06 Z4 M Roadster

[john-e89]

Really enjoying this thread, it's something I'll be doing to my M next year all being well.

Top work chaps.

[Gazhyde]

Thanks John and Lynchey, another day in the 'shed.

Honestly I'm knackered after two full days of working on the car, so I'm going to cheat for now and just post a link to todays post on my full build thread. Just spent an hour since I've got home sorting pics and writing stuff up, and I don't have the energy to replicated here. I have an appointment with the shower, grab another coffee and count some sheep through my eyelids in my fave chair for a while

Enjoy it gents, we are having a rare Sunday shift tomorrow to get it down on the wheels and go for a test drive. Obviously will need a full geometry carried out on it, but should be good for a test drive. Will try and bring this thread inline with the main build thread tomorrow along with a Day 6 update.

https://zroadster.org/threads/2006-e85- ... ost-709347

[Gazhyde]

Day six complete, write up on the list for tomorrow. Got home 45 minutes ago and am rather knackered... Here's one pic to tide you over...

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[Gazhyde]

Day 6 - Reassembling everything else and the finishing touches....

There isn't a huge amount to the final reassembly day, mainly because it was busy and the majority of it was fairly dull like refitting the exhaust and the large amount of undertrays.

There were a couple of jobs which weren't really related to this which I've detailed on my main progress thread elsewhere.
- S54 Chain Tensioner leak
- Braided clutch line / clutch delay valve removal

What we do have is some nice pics of the shinier stuff that people like, so lets kick off with some brakes!

EBC Yellow Stuff and HEL braided brake lines are our combination of choice - expensive but entirely worth it. There are 6 lines in total for the Z4M, 4 rear and 2 front. £150 for the lines and £80 for the pads.

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Brand spanking new BMW OEM 328mm rear discs. These are the same as fitted to the E46 M3 and 12mm bigger than the Z3M front discs. Pleasantly affordable at £215 a pair delivered from a BMW dealer through eBay. You can see the HEL braided lines joining the hard lines in the upper left. The discs have had a light spray coating of lacquer to make them easier to clear later on.

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Calipers look ace with a fresh coat of paint. If you look closely at this picture you may see a slight issue we rectified later in the day!

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Front brake tidy up as everything looks good up front except for changing the brake lines.

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Trev gave the front discs a good clean up and coat of silver Hammerite. Refitted the calipers. You can see that the exhaust mid sections have been refitted as you can see the cats hanging in the background.

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Checking wheel nut torque after first test drive up the top of the road and back. You can see the laquer overspray is starting to be scuffed off by the pads.

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and that's it for the technical side of the rebuild - she's finished!

I've driven maybe 25 miles since wheels down, a couple of shield rattles but no major clangs or clunks! Need to get it booked in for a full 4 wheel geometry this week before I get a full understanding of how she drives.

Will be doing a couple more posts over the coming weeks where I'll be talking about how much more awesome it drives (it does even with iffy geometry), and cover some of the parts costs and how much labour we put in to this build.

[grannyknot]

Interested to hear what you have to say on how the new bushings feel, did you notice any visual signs of wear or fatigue on the original bushing you removed?
Also, do you off hand if the Hammerlite paint has a similar chemistry as the POR15 paints?
Thanks

[Gazhyde]

did you notice any visual signs of wear or fatigue on the original bushing you removed?

Majority of them had failed either visibly or pretty much fell out when removed, particularly the rear trailing arm bushes which had failed both sides. Will see if I can find some more pics to post, but you can see some in the first few updates on this thread.

As for the Hammerite question, no idea!

[patriot66]

Brilliant thread ! Excellent work, great info and great photos. This will be my project possibly autumn next year, so this will come in handy for reference

[Joycey]

It's worth adding some very specific details, we both really need to sit down and compile them all, for example before refitting the diff you need to install both passenger side arms to the subframe, this is because the diff is not central and clashes with the bolts.

[Gazhyde]

Brilliant thread ! Excellent work, great info and great photos. This will be my project possibly autumn next year, so this will come in handy for reference

Cheers, I like doing the write ups almost as much as the spannering!

Think I took something like 170 picture in total, will likely put them somewhere and post a link to all of them in case the ones that didn’t make the thread are useful.

[craig3.2]

Good thread,and good work,Gaz

[Gazhyde]

Some random musings pulled from my full build thread update today about how I feel the car has changed since the rebuild.

First chance to put the rebuilt M through it's paces on a long roundtrip of about 250 miles today over a wide variety of roads surfaces, motorway/dual carriage way and the best and worst A/B roads on offer in Niall's stomping grounds. Had a full Hunter geometry earlier this week, which got all the wheels pointing in (mostly) the correct direction (need new track rods up front now!). I'll do a post at some stage about that whole thing, because there were some issues with the tech who carried it out.

Negatives first. A tiny bit of a squeak from the brakes at low speed up to about 25mph. I'll go back in there with some copper grease at some stage.

The positives are literally everything about how it drives/handles. It's so composed over all surfaces including some of the wash board / potholed sections, nothing phased it. It's firmer for sure as there is no slop/give from the failing bushes but I guess this is as close to how it came out the factory, since it left the factory. That firmness doesn't translate at all in to harshness in any form. On the motorway on cruise control it just sits quite happily plodding along.

Before we started this my biggest issue with the car was accelerating from a junction (for example) would trigger the traction control and it would then drain all the power till it sorted itself out. Now this is entirely as per design and how TC works, but it was happening a lot and was really causing more issues being overly intrusive. The difference now under the same conditions is that the TC light flickers (as a warning) but it doesn't back the power off as aggressively. This means that when I'm pulling out at a junction "under load" I don't end up in a TC induced mess with traffic bearing down on me. This coupled with the clutch delay valve (now removed) causing it to kangaroo was just getting me very nervous at junctions. Now it just hooks up the power and away I go, no drama or panic - pretty much like how BMW designed it I reckon.

Maybe if we'd have carried all this out on my previous 3.0si I'd have been more in love with it, but honestly it just wasn't the car to invest this kind of time, effort and money on - so I wouldn't have. The moral of this tale I guess is find the right car, then you'll likely want to keep it and lavish attention on it.

[Wassup]

Fascinating read and great work...I've been toying with a similar plan for my Z4M but them remembered how much effort it was doing an underneath restoration my M3 a few years back. Fortunately the z4m shares many of the same parts with the M3 so parts (rear axel, brake caliper rebuild kits, nuts and bolts etc) are readily available from places like Autodoc which helps with the M tax!

[Wassup]

Also bit of a shameless plug... I'm selling a "nut and bolt restoration" package over on the for sale section on the market place, did have some interest from a fellow member but seems to have gone quite so thought I'd plug it in this thread.