Andrew Posted June 8, 2023 Share Posted June 8, 2023 This post covers how to correctly build your front struts ensuring correct alignment of the top mount to the lower forked end and then two methods of how to install them. Tools needed Trolley jack and axle stands 13mm socket E16 Torx socket E20 Torx socket 17mm socket - wheel bolts 18mm socket including go thru socket, spanner and crows foot. 21mm socket and spanner Torx T40 bit 6mm Allen key Pry bar for persuading Hammer for firmer persuading Proper set of spring compressors and tools to operate this Ratchets and breaker bars. Again go big or go home. Torque wrench - 140Nm minimum. I'll cover how to build a new strut first ensuring the thing is aligned properly without using the complicated BMW of lasers etc then the removal and re-fitting on the car. This method is the same if you are just replacing a broken spring which is what I did back in May 2020 (lost on old forum) and then in September 2022 I fitted two complete new struts along with some suspension arms. Thus the pictures will show two different ways of installing depending on what you are up to, although if just doing a strut or spring a combination of the two methods would be best I think. In BMWs quest to create the ultimate driving machine, the front suspension on this 5-Series, unlike the previous generations of 5ers utilizes double wishbones (upper and lower) which means there is no swivel bearing in the top mount like there is on the traditional McPherson strut setup. The strut on the F10 has a forked lower end which sits astride the lower wishbone and the top of the strut is fixed to the inner wing with three bolts, using a top mount. This means it is critical that the alignment of the top mount is exactly in relation to the forked end of the strut. The method described for my MSport suspension equipped F10 5-Series may not work on cars with xDrive (4x4) as there is the front driveshaft in the way. For cars with VDC (variable damping control) as there is more equipment fitted to the strut making it too big to be removed without firstly removing the upper wishbone, or removing the lower wishbone from the subframe which requires a bit more dismantling such as removing the underbellies and the one around the track rod to gain access to the wishbone subframe bolt but I'll cover that later. Standard SE or Luxury suspension will have a longer strut which may also necessitate the need for the upper wishbone to be removed to get the strut out. This procedure is the same on the F11, touring/estate models as their front suspension is identical, although as thanks to @Cadwell Parker, we have found out that there is a subtle difference in part numbers at least between the front shock absorbers between the F10 and F11 models. I'll demonstrate the building of a new strut as I've got clearer pics of that and you can see everything a bit better. Top side of the upper spring pad and underside of the new top mount The top mount has an arrow on its side, this lines up with a corresponding mark on the upper spring pad. The new top mounts regardless of supplier come without any threads cut into the aluminium. The new strut top mount to inner wing bolts are special tapered and slightly triangular in cross section to cut the threads when you install it. It's effectively a self tapping screw. Thinking that I'd make life for me easier, I decided to cut a M8x1.25mm thread in one hole on each mount so I could easily fit the strut solo. Lets face it if you are re-using a top mount the threads will already be there so what's the difference. BUT YOU DO NOT NEED TO DO THIS! Offside strut alignment Note the red line which lines up with the top mount arrows and what is the inner leading edge of the lower forked end. This how to align them. Thus the top mount effectively describes the position of the lower spring pad on the shock absorber. Both spring pads have clearly defined spring ends to which the ends of the spring must butt up against. This is what my front offside strut looked like after removing it from the car in May 2020 when I replaced just the spring and bump stop Before I started compressing the spring, I assembled the lower pad on the shock absorber, followed by the spring and then the upper pad and top mount in relation to the alignment described above. This gave me the correct orientation of everything in relation to each other when the forked end of the shock absorber was horizontal when building the strut up in the spring compressors. Top of new spring hard up against its 'stop' on the upper pad. The top mount marks are on the left hand side of the top mount. Bottom end of the spring hard up against the lower spring pad 'stop'. Now the scary bit of compressing the spring to make it all fit together! With my spring compressors squeezed good and tight in my vice I start compressing the spring with the new bump stop/gaiter assembly already located inside it. Note the orientation of the ends of the coil spring. This has been placed in my compressors so that the top mount will be give or take aligned properly in relation to the lower forked end (when its horizontal, you'll see that in the next two pictures below), although with this type of compressor will make adjusting the alignment easier if required later. Stand parallel to the compressed spring (treating it like a grenade/loaded gun, its the same thing if it comes out the compressor!) at all times just incase! While gritting your teeth and shutting your eyes, continue compressing the spring until its short enough to carefully thread the shock absorber spindle thru the spring and bump stop without disturbing the position of the lower spring pad in relation to the shock absorber. Get that top mount on and start the new spindle nut on its thread. Take a deep breath as you have now at least somewhat restrained the beast! Note the top mount marks (2 o'clock position) are give or take in line with that lower inner leading edge of the bottom of the shock absorber. The roll bar drop link bracket is on the out/wheel side of the shock tube and points forward. Adjust the position of the top mount spring and pad assembly as one so that it lines up correctly. You need to treat it as one unit to make sure the ends of the springs are still up against the pad stops. Nearside strut alignment, compare that to the offside above previously The two yellow arrows pointing to the right at each end of the yellow line indicate the alignment you are trying to achieve. The yellow arrow pointing to the left is the inner edge of the roll bar drop link bracket. This is the nearside strut. The offside strut is built in the same way except its handed as the shock absorbers are unique to each side of the car. Using a 6mm allen key (genuine shocks) or in my case (TRW shocks) a Torx T40 counter hold the spindle of the shock while you tighten the new 18mm nut with a go thru socket and ratchet. As my 3/8" torque wrench can't torque in the reverse direction, I tighten it up to "that feels about right torque". If you do have a torque wrench that can do left had threads at a low enough torque, you can use it by turning the spindle anti clockwise until it clicks at 34Nm while 'tightening' the nut on your go thru ratchet. Just to emphasise the need for a decent set of spring compressors, these front coil springs need and almighty amount of compression on them to get them to fit over the shock absorber spindles, once the spring is on and held in place with the top mount nut, the spring pressure pulls the spindle of the shock absorber further out that its normal extended position. The strut that has been built up is noticeable 'longer' than the one that hasn't got the spring on it. Picture below shows just how much it needs to be compressed by. Yes you can do it with the screw type ones but it took me 2 hours to compress, install and then uncompressing the spring ensuring the alignment was maintained. May 2020 I had to put two turns of each screw before removing it from the vice, rotating it and clamping on the next compressor before two more turns. May 2020. With the yoke type compressor it took me 20 minutes to build the strut and its alignment was fine. Now to get the front strut in and out of the car. This is much easier than doing rear struts on the F10 that's for sure. Jack up and support the front axle of the car. Ironically the pictures used in the link above are from when I tackled the broken spring in 2020! Remove the relevant front wheel. Undo and remove the drop link to the strut. Counterhold the link balljoint with a T40 while undoing the nut with am 18mm spanner. Turning the steering may help you manoeuvre the link out of the strut. Next slacken the lower strut bolt. 21mm nut and a 18mm bolt head which is inserted from the rear. Remove the nut and leave the bolt for now. Slacken all three of the strut top mount bolts with a 13mm socket or if someone has been in before and done the job correctly... ...E16 Torx socket and remove two of the bolts. There are two ways of getting the strut out of the car. If you just want the strut out and you don't have any of the fancy VDC (variable damping control) as there is more equipment fitted to the strut making it too big to be removed without firstly removing the upper wishbone (BMWs method) or removing the lower wishbone. I'll cover the two different methods I used. Remove the lower bolt and pull the strut towards the hub/outwards from the car. Push down on the hub and lift the strut up and over the wishbone to the rear of the car. It's still being held to the car by one of the slackened off top mount bolts so it won't drop out and gives you the wiggle room you need. Hold the strut with one hand while undoing the last top mount bolt with the other hand and lower the strut out of the car. Do what you need to do to the strut before putting it back in. Re-fitting is reversal of removal, press down on the hub to allow you to lift the forked lower end of the strut back over the lower wishbone. New bolt inserted from the rear and nut fitted to the front. I had to persuade the bolt thru the hole slightly. An alternative method I last used which I found a bit easier was to have removed the lower wishbone from the front subframe. This allows the wishbone to hang down from the hub and can be easily moved out the way to allow the strut to drop out vertically, which I'm certain would be the way to do it if you had VDC. The wishbone subframe bolt is a much easier option that removing the wishbone steering knuckle ball joint! It is certainly easier to re-fit the strut with the wishbone disconnected from the subframe, than trying to re-fit it with the wishbone in-situ. This is the thread on how to remove a wishbone, but I've shortened the procedure here After slackening off the top mount bolts and removing two of them, proceed as follows. Slacken the wishbone to subframe bolt with an E20 socket on the bolt head and an 18mm spanner on the nut. Remove the nut and bin it. Watch out for the track rod gaiter when you remove the bolt, bin it too. New nuts and bolts must be used on re-assembly. Remove the strut lower bolt to the rear, bin it along with its nut. Persuade the wishbone to leave the subframe and allow it to safely dangle from the hub and simply undo the last strut top mount bolt and lower the strut vertically out from under the car. Don't get hung up on the fact that its a new wishbone also being fitted. Again, do what you need to do to the strut. To reassemble Position the strut under the car.. And lift it straight up into the inner wing, that's a new top mount bolt ready to start in the hole I had pre-threaded. Start that bolt to take the weight of the strut. Lift up the wishbone inbetween the struts forked lower end (this is a why the alignment of the top mount to the bottom of the strut is critical) and persuade it back into the subframe. With a little bit of help to support things, get the new bolts back in place. New subframe bolt inserted from the front. New lower strut bolt inserted from the rear and re-connect up the drop link to strut also. Now to tighten everything up. New top mount bolts E16 Torx socket to 28Nm. The new bolts cut their own threads just fine in the new top mounts. The one I had cut thinking it would make life easier did help a bit as I was flying solo on this job but it is not essential as the wishbone will help keep the strut in position. Before you can tighten the lower strut bolt and the wishbone subframe bolt, the car must be back at it's normal ride height. You can do this with it on ramps... ...but it's not that easy. Alternatively you can jack up the steering knuckle paying very close attention to make sure you don't lift the car off the axle strands so that the gap between the upper wishbone and the inner wing is 90mm. Wishbone to subframe bolts gets tightened to 85Nm followed by 180 degrees. Make some marks so you know when you have turned thru 180 degrees... while ensuring the bolt head doesn't turn. Correctly tightened and not that bad to do with a long enough lever. After tightening the lower strut bolt to 90Nm, it then needs tightened a further 180 degrees. Note bottle jack maintaining the suspension at normal ride height in bottom left corner of picture. Once the marks align you know you have achieved 180 degrees. Having the suspension lifted up to ride height without the wheels in place, made tightening the suspension bolts much easier as you have room to swing on the end of a 750mm long breaker bar. Tighten the drop link nut using a crows foot spanner to 45Nm while counter holding the balljoint with a T40 bit. And then tighten a further 45 degrees, I just heaved it around with an 18mm ring spanner while counter holding it with the Torx bit. I use impact grade torx bits for these jobs as I kept breaking the ordinary grade bits doing these things as they can't withstand the torque Put the wheel back on and lower car to the ground and torque wheel bolts to 140Nm Done. 2 3 Quote Link to comment Share on other sites More sharing options...
Steve84N Posted June 8, 2023 Share Posted June 8, 2023 When I did mine last year we had difficulty with the spring compression, it destroyed two sets of those cheaper tools by chewing through the threads and it was quite frankly dangerous when they slipped a few times. In the end my friend with a small garage unit invested in a hydraulic press tool which had the power but even that only just compressed them enough. We got somewhat inventive with the method for alignment. By dry fitting the mount and damper to the car without the spring we then marked a position on the strut to line up with the arrow on the top mount. However, I had the arrow on the top mount facing outwards whereas it looks like the correct way it ends up facing forwards. My top mount holes and the fork of the damper lined up but I guess my spring is 120 degrees out of phase. I can't see how this will matter though as the damper/spring move in a linear direction so the amount of force needed to work in practice will be the same? 1 Quote Link to comment Share on other sites More sharing options...
Andrew Posted June 8, 2023 Author Share Posted June 8, 2023 Totally agree with you @Steve84N When I first did this job in May 2020 I nearly backed out as I was nervous about the compression on the spring, but given it was still lockdown I might have struggled to do much else. So just dug deep and clenched everything I could clench! I wouldn’t do a spring as tough as an MSport one without the yoke type. I wouldn’t worry about the spring being out of phase as the top mounts are 120 degrees between the bolts, unlike F10 rear strut top mounts so it won’t matter at all. The arrow on the top mount is an easy identifier, but if you have the middle of any ‘buldge’ on the top mount (around its bolt hole) lined up as I’ve shown you’ll be rightly. Sounds like you did the same thing just on a different way that worked for you. Saying that I’ve not long helped a mate with a strut (swivel bearing failed!) on his VW T5 Dampervan and he just used the thread type compressors without issue, but as it’s a proper McPherson strut there is a swivel bearing up top meaning there is no need to worry about alignment of the spring to the shock. 1 Quote Link to comment Share on other sites More sharing options...
Steve84N Posted June 8, 2023 Share Posted June 8, 2023 I've been finding that working on the F11 is both harder and easier than other cars. There's more difficult and quirky procedures like the suspension but there's generally a decent amount of room to get to things, certainly more so than on a 3 Series. 1 Quote Link to comment Share on other sites More sharing options...
Andrew Posted June 9, 2023 Author Share Posted June 9, 2023 9 hours ago, Steve84N said: quirky procedures You mean precision honed German Engineering! 😆 1 Quote Link to comment Share on other sites More sharing options...
Wilmslowsi Posted April 22 Share Posted April 22 Hi Andrew, Great Post! My F01 has had slightly unusual handling/mild instability over bumps since I broke a front coil spring and my local garage replaced springs on both sides. It been driveable but just hasn't felt quite the same as it was, despite numerous hunter alignments etc. Anyway, after reading your post I had a look at my front struts. The arrow markers on the top mount point straight outwards towards the ball joints on the each upper wishbone, which is perhaps the obvious assumption, but it looks from your article that should actually be in alignment with the rear of the fork prong on the side of the drop-link mount. I don't want to disassemble the strut if I don't have to as I am not replacing anything, but if I remove it from the car and compress the spring leaving the top mount in place, will I be able to rotate it to your suggested orientation and uncompress the spring, or is it essential to completely take it apart to line it all up? Cheers, Simon Quote Link to comment Share on other sites More sharing options...
Andrew Posted April 22 Author Share Posted April 22 Hi @Wilmslowsi It should not make a difference as the top mounts are symmetrical. So there is no need to do as you suggest to “realign” it. If you drove it with a broken spring you might just have compromised the shock and I would suggest a pair of shocks on the front axle might help your symptoms Quote Link to comment Share on other sites More sharing options...
4aceman Posted April 22 Share Posted April 22 Were the bump stops replaced? M-sports have different, shorter, bump stops. Regular bump stops on m-sport springs will cause the car to ride on the bump stops, ruining the ride. Missing/shorter bump-stops will also have an effect. These newer BMWs are designed with the bump stop behaving as a secondary spring even in normal driving. Quote Link to comment Share on other sites More sharing options...
Wilmslowsi Posted April 22 Share Posted April 22 Thanks Andrew, I am a bit confused. The arrow on the top mount lines up with the arrow on the upper spring pad, both facing directly towards me as I look at the wheel arch straight on. The the spring orientation is defined by it fitting into the top and bottom spring pads, so the arrows on the upper spring pad and top mount are not pointing at the back of the fork, they are both pointing straight down at the center of the fork/lower control arm? Does that mean the spring has the wrong rotation, or not? Please see pic - based on your photos it 'feels' to me like the top mount/spring and upper/lower pads all need to be rotated so the matching arrows on the top mount/top pad, point at the back of the fork rather than being central? If that makes sense? Good point re: dampers, I am sure they would benefit from a refresh, but having just learned of the strut alignment requirement I want to ensure I understand it properly and am sure its all correct before moving forward. Quote Link to comment Share on other sites More sharing options...
Andrew Posted April 22 Author Share Posted April 22 No as long as the spring ends are fully against the spring pads it will be fine. The spring and top mount are correctly aligned every 120 degrees of rotation. I built mine with the top mount arrows lining up with the forked end as a reference. It could be rotated thru 120deg and it would still all line up but there is no way that I know of without using laser alignment. Perhaps your garage had another way of lining it all up. Quote Link to comment Share on other sites More sharing options...
Wilmslowsi Posted April 22 Share Posted April 22 Thanks Andrew, so effectively there are '3 ways' it can be set up and still be aligned, it just depends on which reference point is chosen (any one of the three 'bulges' on the top mount could be used to line the top pad up with and work down from. So in my case, its probably the next bulge to the left on the pic that has been lined up to the fork. 1 Quote Link to comment Share on other sites More sharing options...
Andrew Posted April 22 Author Share Posted April 22 Yes You’ve said it better than me. Quote Link to comment Share on other sites More sharing options...
4aceman Posted April 22 Share Posted April 22 (edited) 39 minutes ago, Wilmslowsi said: Thanks Andrew, I am a bit confused. The arrow on the top mount lines up with the arrow on the upper spring pad, both facing directly towards me as I look at the wheel arch straight on. The the spring orientation is defined by it fitting into the top and bottom spring pads, so the arrows on the upper spring pad and top mount are not pointing at the back of the fork, they are both pointing straight down at the center of the fork/lower control arm? Does that mean the spring has the wrong rotation, or not? Please see pic - based on your photos it 'feels' to me like the top mount/spring and upper/lower pads all need to be rotated so the matching arrows on the top mount/top pad, point at the back of the fork rather than being central? If that makes sense? Good point re: dampers, I am sure they would benefit from a refresh, but having just learned of the strut alignment requirement I want to ensure I understand it properly and am sure its all correct before moving forward. Why is the dust boot not attached to the bump stop? What's that on the lower dust boot holding it in place? edit: sorry, I think i'm being stupid here. Bump stop seems okay, but I do believe the dust boot has the lower half torn off Edited April 22 by 4aceman Quote Link to comment Share on other sites More sharing options...
Wilmslowsi Posted April 22 Share Posted April 22 Hi, I don't know to be honest, I've not had the struts out of this car myself so it will be as the garage handed it back. Taking a screenshot from the video I took at the weekend, it looks like the dust boot is at the bottom of the strut and the bump stop has separated and is held at the top. I did have it up on stands with suspension fully extended just before I took the video. Being paranoid I am now worried I may have a slightly bent strut from a pothole strike (under a puddle), as the FR camber also wasn't great when I last had it checked (was positive on that one side but just about still 'green'). The passenger side of the car rides a bit higher than the drivers side too, more pronounced at the rear for some reason! Quote Link to comment Share on other sites More sharing options...
Steve84N Posted April 22 Share Posted April 22 For what it's worth @Wilmslowsimine is aligned like yours and the front rides a bit high since I fitted new M Sport dampers. I even had the wrong dampers fitted at first before buying the M Sport ones, but no change in ride height as I expected. To me it's logical that the orientation makes no difference like @Andrew says, so long as the strut fork lines up with the arm at the bottom. I did this by mounting the damper without the spring and making a reference mark as I didn't have a laser. Something still bugs me that maybe the top mount orientation does make a difference to ride height. The repair manual is quite strong in its wording about the spring orientation and negative effects if it's not right. I may get some Eibach springs at some point and then refit as per Andrew's guide. Quote Link to comment Share on other sites More sharing options...
Wilmslowsi Posted April 22 Share Posted April 22 Yes I like things on my cars to be 'just so' and start to question everything until I am satisfied I've found whatever 'sweet spot' gives me peace of mind! Despite agreeing with Andrew logically and assuming they are aligned fine, I still feel tempted to pull them off and build them like he has done, which is supported by other info I've found on the internet just so mine looks like that (top mount/top pad arrows pointing at each other AND the back of the fork)... Even if I did all that and it made no difference, somehow I would feel better... 🙂 1 Quote Link to comment Share on other sites More sharing options...
Steve84N Posted April 22 Share Posted April 22 @Wilmslowsi likewise! Please let me know on here if it changes anything. Quote Link to comment Share on other sites More sharing options...
Wilmslowsi Posted April 22 Share Posted April 22 Will do, although hard to get enough time and have to prioritise apparent leaky ZF6HP26 gearbox... only serviced 4000 miles ago and removed undertray full of ATF! Only just done all glow plugs, controller and valve cover.... never ending fun 🙂 Quote Link to comment Share on other sites More sharing options...
Andrew Posted April 22 Author Share Posted April 22 1 hour ago, Wilmslowsi said: Despite agreeing with Andrew logically and assuming they are aligned fine, I still feel tempted to pull them off and build them like he has done, which is supported by other info I've found on the internet just so mine looks like that (top mount/top pad arrows pointing at each other AND the back of the fork)... Beware of what you read about F10 BMW's on the internet, most of it is put there by idiots like me.🤪 1 hour ago, Wilmslowsi said: Will do, although hard to get enough time and have to prioritise apparent leaky ZF6HP26 gearbox... only serviced 4000 miles ago and removed undertray full of ATF! Only just done all glow plugs, controller and valve cover.... never ending fun 🙂 What was that on the 740d or X5? Was the leak from the connector plug/sleeve? Notorious weak point on the 6HP, one of many.... The 8HP in your F10 is far more reliable than the flaky 6HP versions. Quote Link to comment Share on other sites More sharing options...
Wilmslowsi Posted April 24 Share Posted April 24 The gearbox issue is on the 740d, its a very high spec early 2009 I've had for 9+ years and looked after very well. I had the box serviced about 8K ago (pan/filter & fluid) but they didn't offer the valve body tubes, figure of 8 seal or electrical connector sleeve at the time... so I bet it is the the connector sleeve that's leaking and will need the pan/fluid removing to get to the release catch! Same box on the X5 and yes the F10 8 speed (also on later LCI F01) is much better... Arguably I don't need 7 series, 5 series and X5 but I like them... would also like E46 M3 too 🙂 Quote Link to comment Share on other sites More sharing options...
4aceman Posted April 24 Share Posted April 24 3 hours ago, Wilmslowsi said: The gearbox issue is on the 740d, its a very high spec early 2009 I've had for 9+ years and looked after very well. I had the box serviced about 8K ago (pan/filter & fluid) but they didn't offer the valve body tubes, figure of 8 seal or electrical connector sleeve at the time... so I bet it is the the connector sleeve that's leaking and will need the pan/fluid removing to get to the release catch! Same box on the X5 and yes the F10 8 speed (also on later LCI F01) is much better... Arguably I don't need 7 series, 5 series and X5 but I like them... would also like E46 M3 too 🙂 Another drain will not be the worst idea anyway. The initial service would’ve only changed about half the fluid, so there’s benefit to doing another Quote Link to comment Share on other sites More sharing options...
Andrew Posted April 25 Author Share Posted April 25 On 24/04/2024 at 16:21, Wilmslowsi said: but they didn't offer the valve body tubes, figure of 8 seal or electrical connector sleeve at the time... They need doing! They age, go hard, and without you knowing they start to leak internally so you end up loosing internal pressure which means the hydraulic force applied on the clutches reduces and they start to slip and then without warning, you are suddenly on the hard shoulder of the M74 with no drive and the orange cog of death illuminated on the dash and are looking at a rebuilt transmission at the same price as the trade in value of the car. External leak on the 6HP will be the connector sleeve, guaranteed. Quote Link to comment Share on other sites More sharing options...
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