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F55/F56/F57 Stock Problems/IssuesDiscussions related to warranty related issues and repairs, or other problems with the OEM parts and software for F55/F56 MINI Cooper AND Cooper S models.
Gee, who would have thought the OEM was ignorant enough to bond the sway bar bushings to the sway bar. For your info a sway bar is nothing more than a torsion bar spring, which begs the question why would the OEM prevent the sway bar from rotating in the "sway bar bushings" as to do so would induce undue preload of the sway bar into the strut suspension, which is probably what contributed to the failure of the strut mount bearings in the first place along with a **** poor bearing design and springs that are at best loaded improperly on the spring seats because of their design. Those in the know would think it crazy to bind up the sway bar from rotating within the bushings as the suspension moves as each wheel is independently sprung, not a solid axle type set up, and the sway bar is there to help with body roll under cornering as the wheels, spung separately are in different locations along their travel relative to each other and the sway bar counteracts the roll or lean of the body with its additional spring loading to compensate. To make the sway bar part of the springing of each wheels by inducing preload defies logic and those that have set up front suspension always (zero) the preload of the sway bar as the car sits on its suspension in what is termed normal position. Maybe BMW has a reason for doing such ignorance, but I am sure their customers don't like having take their cars in for unnecessary service because of such ignorance.
However you feel, it's a common approach using rubber bushings.
That ignorance you claim has been way since the invention of sway bars. There still is rotation within the rubber.
Rubber control arm bushings use the same theory.
There is good reading published by the Society of Automotive Engineers discussing various
bushing techniques, one being bonded, another with compressively griped bushings.
Compressed bushings were the standard, until aftermarket started using urethane.
Bushing characteristics of Stabilizer Bars
L. N. B. Gummadi, H. Cai, S. Lin, X. Fan and K. Cao
Vision Corporation.
Yes, and being a former aerospace engineer myself also worked on Indy cars (Dan Gurney's 1984 stock block effort, first graphite/bonded honeycomb composite body on an Indy car, which I built the composite shop, molds and first two bodies for Dan), sway bars have always had free rotational movement with the suspension and those urethane bushings you mentioned that get rid of the stressed rubber are actually greased and allow rotation as I now have on the front suspension of my Mini. Didn't bother to initially change out the sway bar bushings but could not figure out why the sway bar had no free rotation until I did the 8 hours of work to change them out with urethane. Poof the noise problem disappeared. I wrote BMW and asked if they have done an FMEA on their strut mount failures, which according to my dealer's senior tech they change out a lot of strut mounts due to bearing failures. No reply though. As I stated there is probably a reason that BMW designed the bushings on the front suspension with the stressed rubber design (cost being the top one I am sure), but as in real life usage, some things designed on 3D cad like the Mini don't take into account actual producibility, repairability and normal usage, boy found that out on the F-35 when I was in SDD (Systems Design and Development phase) and once production started, almost every 3D cad modeled part had to be changed as producibility and longevity can't be simulated in the 3D modeling programs. I worked in El Segundo for 28 years on numerous aircraft and spacecraft programs, but prior to my career there did race car stuff. Oh I was not a design engineer, but production engineer (ME) and ended my career as a Quality engineer. MEs are termed "manage everything related to production" where I worked, tooling, processes, materials, producibility issues, and quality. Not a bad machinist either. Cars are pretty simple compared to aircraft, as failures don't usually kill the occupants of the car, in airplanes a failure can be catastrophic.
Thanks Chamberlin 1. Boy and I thought I was going crazy running into this ibonded rubber sway bar bushing issue and OEM has apparently bought into this idea, that was patented. Hey I have a patent, but it actually is being used and works for F-35 and doesn't destroy strut bearings. I suppose they will patent any idea even stupid ones. Gee a 24mm torsion bar in addition to the messed up OEM coil spring design alll working on that poor plastic bearing at the top of the spring, know wonder the techs at the dealership have practice replacing strut mounts.. In my photos I will show you guys how utterly messed up the F56 coil spring is designed, it will not even sit on a level floor on either end (when removed from the car) without falling over and when installed only contacts about 40% of spring end on the spring seats. Mini-block designed springs, Lsjesfords in Sweden makes replacement springs OEM rate for under $30 a piece through ROCKAUTO.
In my photos I will show you guys how utterly messed up the F56 coil spring is designed, it will not even sit on a level floor on either end (when removed from the car) without falling over and when installed only contacts about 40% of spring end on the spring seats. Mini-block designed springs, Lsjesfords in Sweden makes replacement springs OEM rate for under $30 a piece through ROCKAUTO.
I'd be interested in hearing your opinions on the design of various lowering springs, such as H&R, CravenSpeed, etc.
Well, any of the aftermarket lowering springs are a way to get the car lowered without resorting to coil overs, though if you add lowering springs you will have to put on adjustable sway bar links Oh as long as the ends of the lowering springs you consider are sitting flat and not curving upward( you will understand from the photos I am doing tomorrow), you should be fine.. I don't recommend Godspeed sway bar links as both ends of each link are right hand threads, so it becomes cumbersome to adjust and zero out your sway bar preload with the car in normal position. Oh, the newtis is back up and running after being shutdown for 3 months. You have to register and such, but has a wealth of information about fastener torque values, and the dealer methods of repair of the car. As far as camber plates, I looked at Kmac, Vorslag...etc, but found a company in England that is a specialist in top mounts (ie camber plates), fairly reasonable priced compared to Kmac or Vorslag, CNC made with 6062 aluminum and not only allows for camber adjustment but also caster adjustment. Here is the link; https://www.compbrake.com/product/bm...lly-guaranteed I have a set and paid about $335 shipped ($280 for the set converted from Euros) for the F56 (later model F56 after 2016 the bolt pattern changed as did the strut mount) as the f56 was in production prior to 2016 the strut mounts were changed over to the current models (as pictured above as noted in my initial thread.). I believe the Compbrake are much better than the Vorslag and a lot more reasonable. Very well made by the way and comes with upper spring seat for 2 1/2" Id springs. You do have to specify the thread for the shock you have, which for stock shocks is 12x1.5mm. Got shipment confirmation from Ceika on my coil over set today, delivery on the 24th. Thinking about doing a video when I change out the OEM/my prototype suspension to the coilovers for you tube, could add it here in the how to's as there isn't much on how to do stuff for 3rd gen Minis. Do/ not follow the newtis info though on removing struts as the swivel bearing is removed from the ball joint with the strut and you don't have to mess with the PITA swivel bearing ball joint alignment when reassembling remember the stressed rubber lower control arm bushings don't allow much room to. Buy a swivel bearing spreader tool (available from ECS tuning for about $8l so you can remove the strut from the swivel bearing while still in the car as it is much easier to remove and replace while aligning the strut base back into the swivel bearing. Total of 5 fasteners to remove to pull a strut: top sway bar attachment nut (10x1.5mm, used a locknu if you replacet), the three strut mount bolts (believe these are 8mmx1.25 x 30mm bolts), and the swivel bearing pinch bolt (10x1.5mm x 85mm long). The newtis recommends all the hardware (fasteners removed) be replaced with new each time. ( now do you think the techs at the dealers really do that??) These are all 8.8 grade fasteners, and most hardware stores stock these sizes and lengths in metric. The pinch bolt on the swivel bearing is a strange bolt though and reuse is recommended once. The 30mm bolts that are used on the strut mount have a buil/non removablet in .200" thick washer under the head, so they can be reused once to. A lot of the fasteners on the car require a setting torque value, then usually an additional 90 degree tightening turn...warning these are stretch bolts that are tightened to just below yield, so reuse is not recommended. I made up some hat washers out of 7075 Aluminum for each end of the pinch bolt to fit in the swivel bearing as I have had the suspension apart now 15 times and also so I could use a standard hex head bolt in lieu of the external torx bolts. I replace the fasteners each time and use 10.9 grade hardware as my podunk hardware store near me actually has the 10.9 metric fasteners in stock. Torque values as follows: Pinch bolt on swivel bearing 37 ft ls, plus a 90 degree turn, strut mount bolts 22 ft lbs, and the sway bar locknut is 43 ft lbs. Oh, standard suspension top shock nut is a 12x1.5mm with 42 ft lbs of torque...don use a .impact to put together anything, take it apart with an impact is okay, but hand tighten, then torque. Any other questions hmu
There is a invite link on my account I set up. Guess there is a club that is offering access to trusted users. If you give me your email I will send you an invite. Not allowed to give out the link on forums. Dave
Almost every fastener on a Mini is either external torx or internal torx. If you think they strip try taking out a front lower control arm, the bolt for the front bushing is 12mmx1.5 external torx, buried about 6 inches from the access point (front of the subframe) a real PITA and torqued to 72 ft lbs. I stripped both left and right sides and used my multiple fastener head socket to get the damn things out. Fully threaded and over 3 1/2" long. Put in a 10.9 standard hex head 12mmx1.5 and still had a bear of a time getting them torqued up. Oh, and worst fastener is the collar bolt that goes between the front axle hub and the driveshaft, 17mm hex drive and is torqued probably to over 200 ft lbs, it is one of those that is set torqued to 158 ft lbs then rotate 90 more degree and has to be replace each time you remove them at over $24 each. Can't get them at the hardware store but only at BMW/Mini. I have found fasteners to be a challenge on the car to get. I went with 30mm long hex head 10.9 on the strut mounts bolts and made up my own 8620 steel washers for under the bolts. Next project after the coil overs is top plates opposite the strut mount, probably use 2024 T3 for those and get them anodized blue. I have access to a machine shop with all the tools including a CNC lathe and mill and even a injection mold machine. Without the shop I would have to buy most of the stuff I am doing or not do it. Just lucky I suppose.
Stock OEM spring removed from strut sitting on the top spring to strut mount interface end. Note the twist and the gap between the table and the end of the spring.
Here is a closer view of the gap on the lower spring seal end of the spring.
Now sitting on the lower spring seat end, note I am holding the spring up.
View looking down from the top spring seat end to lower spring seat end and the "offset center to center line of the spring.
Better view of the spring offset from centerline of the spring's large and small ends.
as noted in the photos this spring is the OE stock, standard suspension spring, it is not damaged, nor bent, but after carefully looking at the spring I determined the ends of the spring under compression do not sit fully on the spring seat, and yes there are "rubber inserts on both ends that somewhat account for this problem., but when looking at the spring compressed on the strut without the rubber inserts top and bottom about 40-50% of the supposed flat part of the end of the spring that sits on the spring seats is actually sitting on the seat and to bent the spring "flat" so more than that would sit flat would take the spring to compress probably close to yield. Now do you understand why the strut bearing are overloaded on that 40-50% area where the spring actually sits on the bearing. All the loads, both compressive and shock loads are not being evenly distributed on and throughout the strut bearing and remember, a coil spring is really a twisted in a coil shape torsion bar spring and when compressed actually rotates the wire just like a straight torsion bar spring. More photos to come.
Oh, forgot to say this about the spring. When assembled the spring compresses somewhat like an accordion as I set up a fixture on my shop press and noted the funky way the spring compressed, did up to 2 1/2 " of compression. The rate of the spring is around 280lbs per inch according to my calculations in the press, but could be off by 10% either way. Note also, the ends of the spring are not ground flat, typical OEM spring, unlike a coil over spring which the ends of the spring are ground flat and the centerline of the spring is not offset as shown in the photos of the OEM spring This along with the lower spring seat locating the spring 5/8" outboard and aft of centerline of the shock. I will have a photo of the lower spring seats I removed from the B4 Bilsteins tomorrow, didn't have time today to get one. The lower spring seats are welded on the Bilstein B4 shocks and the OEM shocks the spring seats are swaged onto the shock. Took about 10,000 lbs of pressure in the shop press to press off the swaged OEM seats and light sanding to clean up the roughness. The B4's on the other hand required checking in the 12x 60" LeBlond lathe and indicated in to machine off the welded portion of the spring seat. Here is some teaser photos of the B4 and my replacement lower spring seat. Still working on the photos to unveil my final design.
L/H B4 without lower spring seat
New lower spring seat without bearing interface. Made from 8620 Chromemoly steel
Sitting on the B4 not installed
New lower spring seat (AL piece) with hard stop. This is one of the prototypes, was used to validate the concept, the black plastic piece on the shock is a centering tool for the steel piece that is removed after the set screws are installed. Aluminum piece rotates on two different roller bearings located in the Aluminum with a double lip seal on top. More photos with more detail to come.
Your right in away, but also wrong as look back at the original photos at the beginning of the thread for the Plastic bearing housing of the OEM strut mount. Do you really think that the plastic is going to not "deform" in the area of highest loading (that 40-50% of the spring that sits on the plastic)? Metal might not deform, but most any plastic will especially with the 958 lbs of suspension load (basic weight of that corner of the car), and then various compressive and shock loads as the spring compresses.
Gheezh makes me happy I have the OEM JCW coil overs ready to install, but I'm still completely in the dark as to what top hats/camber plates to use now!
Chamberlin: Before ordering any top mount, verify what size the id diameter is of the springs you will be using and also the shock thread at the top of the shock as some are: 12x1.5mm, 12x1.25mm, some are 14x1.5mm, and 14.1.25mm. Not sure what spring id the JCW coilovers you are getting, but most coilovers made for F56 series are made for 2.5" diameter springs if they have camber plates with the coilover set, though Godspeed, Megan racing and others that don't have camber plates make you reuse the stock strut mount and the spring id is 3.56" on those spring seats. I have spent over 8 months working up a fix for this noise and OEM strut mount bearing issue. 5 iterations before it worked and change out of basically every bushing on the front end of the car to polyurethane (power flex) and the bonded sway bar bushing once replaced with power flex eliminated the noise with the stock suspension with the bearing moved down around the shcck. The reason I am going with the Ceika coilovers is that they are made by a reputable company (of course in Taiwan), I want to lower the car 12mm max from OEM,, but even BC racing coilovers are made in Taiwan. and only D2 racing coilovers and Ceika could offer a set that allows only 12mm amount of lowering. Oops forgot, you will need wheel spacers for any coilover set, maximum of 12mm thick I found. I got a set of KSP 12mm wheel spacer that fit the Mini gen 3's on Amazon for $34.99
@Davevolved, you've established that these cars MUST have adjustable sway bar links when they are lowered. What is your opinion of the NM Engineering adjustable sway bar end links? I'm still deciding whether I want to go with coilovers, or if I just want to use lowering springs for now. Is there any reason why I wouldn't want to go with the JCW coilovers?
@Davevolved, you've established that these cars MUST have adjustable sway bar links when they are lowered. What is your opinion of the NM Engineering adjustable sway bar end links? I'm still deciding whether I want to go with coilovers, or if I just want to use lowering springs for now. Is there any reason why I wouldn't want to go with the JCW coilovers?
Im not Dave, but I did stay in a Holiday Inn last night!!!
Im lowered on H&R springs, and the bar is still close enough to level. Any lower, I can see the need.
Another caveat, if you run an aftermarket bar, there must be lateral locks, or collars on the bar to prevent lateral movement of the bar.
I ran a bar with without a collar, and there was way too much lateral movement allowed by the NM end links., the end links hit the springs during high G turns.
Mini's solution is to bond the bushings to the bar, and their version of end links.
I switched to the H&R bars the rear being 25mm solid using NM bushings, and NM end links.
The front is H&R 27MM solid I used Moog links, and the bar is pretty level.
The bar was forged perfectly, and I could have used the stock end links, as there was no preload issues.
But as the bar is solid 25mm, I did end up using the NM links just to be safe from breakage.
Probably good to go with the JCW coilovers as they are OEM based so should be easy to set up and install. NM or Alta make very good Sway bar links as they use spherical bearing rod ends and seem beefier than Godspeed's which use ball joint ends very much like the OEMs. As an aside, I am also advocating that the cars even if not lowered with OEM or Powerflex bushings in the front end need adjustable sway bar links as the OEM links are marginal at best, so the preload inherent in the design and be minimized by "zeroing' the sway bar preload as the car sits in normal position ( sitting on the suspension ready to drive, on level surface, with 150lbs in the driver's seat and 14kg in the trunk area and full of gas). I say this because this is supposed to be how the car is aligned (newtis spec) if you took it to the dealer(whether the techs do that or not who knows). My recommendations for what they are worth.
05-17-2021, 02:05 PM
