Reviving a Neglected Z4MR

[0l0dom0l0]

I've been around on the forum for a while but never properly introduced myself - so here I go - complete with my story of how I became the owner of a very neglected 2006 interlargos blue Z4M...

Back in April 2025, I took a punt on what was, and still has been, the cheapest non category/ write off Z4MR that I've seen to date. Naturally, the car had heaps of interest, despite the awful eBay photos and the several declared issues in the advert. I was in Oxfordshire at the time, the car was in Southampton, so not too far away. A phone call to the seller later, I sent a holding deposit (without seeing the car) to secure my interest and headed down the next day to view the car with the intention of bringing it back with me.

Upon arrival, I was greeted by a nice chap called Paul, who had been the owner of the car for several years and done about 2k miles per year in it. Paul referred to himself as an "enthusiast" and I could tell was a genuine guy. I got the feeling he had spent a lot of money on the car over the years and had simply got to the point where he'd decided that the car had started to become more hassle than it was worth.

The car was filthy and had not been cleaned, it looked tired and tatty and the dash was lit up like a Christmas tree.... Perfect!.... Just my kind of project.

Several things stuck out at me:

Cosmetics

1. The front bumper bracket was broken
2. Bumper was scratched and a bit of a mess
3. Missing headlight washer cover and washer insides
4. Headlight was cloudy
5. Roof mouldy
6. Wheels lightly kurbed
7. All badges faded

The car had a fairly complete set of history for it's 112k miles, no rod bearing or vanos work had been done (we'll get to that later), but a recent inspection 2 service had been completed along with a replacement front tie rod, complimented by a long list of "recommended" additional work.

1. TC/ abs/ brake lights on the dash
2. AC not working
3. Diff input seal leaking
4. Exhaust hardware failing
5. Front left brake caliper bleed nipple broken

After a quick test drive with Paul at the helm, I reluctantly handed over the money and headed back in the car.

 

[0l0dom0l0]

On the drive home I was immediately disappointed, the car was handling like a bag of s***. The steering wheel was at about 2 oclock and the throttle had this weird delay where it continued to accelerate for about 0.5 second after I'd lifted off. It was strangely off putting and distracting and took all the enjoyment out the car. It seemed very odd to me as everyone raved about the sharp and precise throttle control on the S54, something was off.

Instantly regretting my purchase, I set out to try and tackle the various issues on the car....

A/C

The first thing I decided to try and rescue was the A/C. When diagnosing any A/C issue, the best thing to do is try and get the system recharged - you get a free diagnosis. If there is a hole in the system, they can't charge it with gas and will turn you away (usually FOC). If the system passes the pressure test then you can normally get an indication on the system health by the remaining gas level in the system - gas left usually means it it just low, no gas but it passes the pressure test means it may still have a small leak. In my case, it was just low on gas, so an hour later and the A/C was working, result!

 

[0l0dom0l0]

Cleaning...

Inspired by my success with the AC, but equally embarrassed by the state of the car, I couldn't stand looking at it anymore and decided to clean it next. The photos make it look better than it was, and hide the full thickness layer of grime on the steering wheel that became sticky when it was touched .

 

[0l0dom0l0]

Many hours later....

 

[0l0dom0l0]

The roof....

The roof was actually working which was a nice touch, but it was imbedded with algae and let the car down. Most people say that you need to re-colour the roof when they get old. I had my reservations and was concerned that any re dye attempt would leave the roof looking patchy.

I employed some autoglym soft top cleaner with a soft brush on a drill and was disappointed. Despite cleaning the roof several times, I was unable to shift the algae. At this point, it was clear something more industrial was required.

So next attempt was to use the soft top cleaner and brush and rather than rinse, I decided to carefully pressure wash off the roof (against recommendation). I could instantly see the algae disappearing and knew that this was way more effective. I left the roof to airdry and was pleasantly surprised by how much fresher it looked. I continued and applied the re waterproofing liquid. That was the roof sorted.

 

[0l0dom0l0]

Christmas came early.....

So with the cleaning out the way, the next thing I wanted to address was the christmas tree dash.

When buying the car, I had scanned the car using Carly and noticed that the ABS module was complaining about the steering angle offset. The car had had a replacement track rod with the recent inspection 2 service, given that the work had been done at a well regarded specialist, I was a bit confused with a couple of things.... why had only one track rod been replaced, and why had the tracking not been completed after this work?

Clearly the alignment hadn't been done as the steering wheel was off centre at about 2 o'clock to go straight, confirmed with no mention of wheel alignment on the invoice.

Anyway, at this point I took the car to have the front toe adjusted. Before sinking £100 on a new track rod so that both were new, I wanted to see if the wheel alignment was indeed the cause of the christmas tree dash. After an hour or so at the garage, I had confirmation that the front toe had been adjusted and the steering wheel was now straight. They had been unable to adjust the one that hadn't been replaced, which was to be expected but the alignment was good enough that the wheel was dead on centre.

A fault code clear with Carly, and an ignition cycle later, the christmas tree lights had gone out! Winner!

More importantly, the weird throttle delay that was absolutely killing the car had also gone away which must have been part of the limp mode the car was in when the dash was lit up. Double winner!

I felt like the car was now safe enough for me to have a proper drive through the Oxfordshire countryside and see what it was all the fuss was about - and this was the point that changed everything for me. The engine, the noise, the roof down - I just had this moment where I said "why didn't I get one of these years ago??".

 

[0l0dom0l0]

I wish I'd never started...

With the cosmetics now in reasonable order, my eyes were continually drawn to the poor state of the wheels. While the curbing wasn't too bad, the paint was flaking with visible corrosion underneath. Up on axle stands to get the wheels off, which would also give me a chance to tackle the other track rod while I was waiting for the wheels to come back...

With the wheels removed, I'd noticed all 4 bump stops had been completely destroyed. I also noticed that paint on both the front and rear springs had started to fail. A quick google revealed no cheap replacement parts for the Z4M suspension, springs/ dampers etc were not available OE and BMW were eye wateringly expensive. I therefore decided to remove the springs and take them to be powder coated with the wheels while I waited for the new bump stops and top mount bearings to arrive from BMW.

I'd also placed an order for several other parts:

1. Rear trailing arm bushes
2. Brake caliper bleed nipples
3. Replacement headlight washer and cover
4. Complete tie rod and dust cover
5. New centre caps
6. Wheel bolts
7. Rear top mounts
8. Replacement ashtray
9. Rear diff seal
10. Replacement gearstick
11. Exhaust hangers
12. Rear brake lines
13. Gearbox mounts
14. Prop doughnut
15. Engine mounts

RTAB

These had been advised by the specialist, despite in the end being there being nothing wrong with them. Fitting them was straightforward using the tool. Remember to follow the BMW instructions for tightening them to the cup so you get them set to ride height.

I'd noticed that the rear antiroll bar drop links were split, I tried replacing the drop link in situ but it was impossible so I decided to remove the rear antiroll bar. This meant I needed to drop the exhaust - not a big deal as this was going to be needed for me to replace the leaky diff input seal.

Removing the exhaust had had an unexpected side affect, the front flange that bolts to the downpipes fell off! Another thing to add to the list....

Removing the exhaust had also revealed some other issues, my front downpipe was unfortunately cracked. This needed to come off to be repaired.

With the propshaft removed, I decided to replace the centre shaft bearing while in there. The original was okay, but just more of "do it while you're there".

 

[0l0dom0l0]

Light at the end of the exhaust...

At this point I was starting to become a little overwhelmed, the exhaust was something that I knew was not going to be an easy fix and everything I touched seemed to direct me to another issue. This post and the previous one spanned over about 6 weeks... it was also the middle of May and the car being off the road was missing prime driving time! Additionally, my brother was getting married and I was about to start a new job, I needed to start getting things back together. Photos are unfortunately a little light here, patience was running out.

I'd collected my freshly refurbished wheels that were looking fantastic, along with the springs.

I'd also set about restoring the front headlight that was foggy, a light sand and then a 2k clearcoat had brought it back to life:

I spent a bit of time refitting the bumper and adjusting the light position. Paul had told me he had previously had to replace one of the headlights and do it seemed the best time to recheck all the front panel gaps. This was the perfect time to replace the front bumper brackets so that the bumper clipped in properly. I'd also fitted the new headlight washer and painted the headlight washer cover.

So back onto more mechanical work across the car, the various parts had turned up and so I'd started reassembling things. Unfortunately I don't seem to have pictures of everything, but at this point I had replaced the diff seal which was quite straightforward, re assembled the front shocks with the new hardware. Replaced the rear damper top mounts. Extracted the broken bleed nipple and replaced the rear brake pipes.

New tools to get the track rod off, it had been giving me lots of grief:

Engine mounts, new vs old....

I'd also cleaned off the rear undertray which was covered in oil:

And freshened up the exhaust with some oven cleaner:

So with the long list of stuff done, I turned my attention to the exhaust....

Removing the manifolds and cleaning up with situation with a wire wheel had revealed that the downpipe was cracked nearly all the way round. I looked up the cost of a new exhaust which at the time was surprisingly reasonable from BMW at £600 odd each side.

Anyway, I couldn't bring myself to chuck a new set of headers on it when I felt like it was quite a simple repair.... except this opened a can of worms .

I ordered some 55mm OD stainless tube off ebay with 1.2mm wall thickness. The standard wall thickness on the Z4M/ CSL headers is 1mm. 1.2mm wasn't ideal but it was all that was available. So that arrived, and it turns out that 55mm OD actually equals about 55.2mm - 55.4mm in real money, which meant that the doughnut gasket wouldn't fit over the tube...

I rang round a few places and a helpful chap in Bicester told me to head up there and he'd swage me up a piece to match - upon arrival he cut me a short length of 2" od stainless with 1.2mm wall thickness, stretched it up to 55mm using the gasket to make sure it ended up a snug fit, perfect! Now I just needed it welded on.

Unfortunately he wasn't able to do it as he was too busy.

Now, I do have a tig welder but welding two sections of 1mm stainless together was not something that I fancied. I asked a good friend of mine if he could give me a hand, but being the impatient individual I am, I couldn't wait for him to come and do it. Many hours later of practise, I decided to give it a go...

So taking me time cut off the old piece and tacked on the new piece:

and then back purged the pipe to get a nice clean weld:

Now onto the cats...

I'd picked up a set of E46 M3 decats. Making them fit was going to be a bit of a hassle and I couldn't be bothered with the MOT hassle either. However, getting hold of any kind of flanges to do a reasonable repair on the mid section seemed impssible. I purchased the decats so I could cut the flanges off to weld them onto my midpipes.

In the end I decided not to use them, there were some differences in pipe diameters that I didn't really have time to mess about with. I was also having issues with the floating flange on the downpipe being cracked, as well as the other flange on the cat section being cracked. This is where it becomes incredibly tricky, as either you need to make a jig so that everything lines up again when it goes back together, or weld it up on the car otherwise you'll lose the critical alignment. Realistically I knew everything needed addressing at once, but I was at this point running out of time to get everything back together.

I decided to just proceed and weld as best I could the original flange back on to the midpipe which came out okay. At least I could get the car back together and come up with a strategy to attempt another repair at a later date.

After a completed clean and degrease of the underside, I had now successfully reassembled everything. What had started on the 6th May, had finally finished on the 20th June....

An MOT with a clean bill of health later (less an advisory for the inner edges of the front tyres, caused by the s*** tracking ) I was back to blasting through the Oxfordshire countryside once again!

 

[0l0dom0l0]

Feeling a bit flat today....

So I'd picked up a puncture - and realised on the morning my friend had turned up to go for a Sunday morning stroll in the cars which was frustrating.

As my wheels had just been freshly refurbished, I didn't want to risk taking them to any old tyre shop to get the tyres changed. I am yet to find anywhere that is able to change tyres without damaging the wheels.

Anyway, front wheels off and new tyres sourced. I went for Michelin PS5 to replace the PS4's which was a mistake as they just do not have the grip. In hindsight I would go for the Conti SC7 or maybe the PS4s next time.

My quest to find someone to replace the tyres without damaging the wheels was unfortunately unsuccessful...

No worries they said, we will take care of it.. they were an alloy wheel refurb shop afterall... well they didn't....

A botched repair later, I took the wheels back off them knowing that my OCD was not going to be happy until they were redone properly. The scratches on the wheel where the wheel weights had been removed were a complete mess and right in my line of sight, plus the scratch from the tyre machine had been repaired so badly I just took it on the chin and moved on.

I also took the opportunity to for a bluemusic in place of my CD changer which was a terrible mistake. Getting to the cables you need on a car with the CD changer fitted is an absolute nightmare. You have to take the entire centre console apart!! For anyone that reads this, do it via the headunit instead! It is so much simpler and easier.

The car had also drawn some unwanted attention while parked on my driveway which was a little disconcerting.

Anyway, new tyres on and now able to play music that I don't even play when driving... I was back to driving around and enjoying the soundtrack of the S54 instead.

 

[0l0dom0l0]

HOLD

 

[0l0dom0l0]

HOLD

 

[0l0dom0l0]

hold

 

[0l0dom0l0]

HOLD

 

[0l0dom0l0]

hold

 

[0l0dom0l0]

HOLD

 

[0l0dom0l0]

hold

 

[0l0dom0l0]

hold

 

[CuppaTea]

Nice car. And kudos for revival.

How much cash did you find under the seats?

 

[0l0dom0l0]

Nice car. And kudos for revival.

How much cash did you find under the seats?

Thank you!

Not enough

 

[paddy wright]

Well done for sorting what looks like a lovely Z!