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DIY: Do It Yourself
Post here to share or improve your wrench turning skills! All BMW E46 DIY tips, tales, and projects discussed inside. Learn to work on your car and know the right BMW parts you will need!

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Old 06-25-2008, 12:25 AM   #1
doit659
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Recommended replacements for a 100,000 mile suspension upgrade?

I have a stock 325i with 100,000 miles, and the dealer told me that I have moderate play in the R/F lower control arm's outer ball joint and a broken left rear spring.

So, I am going to make a purchase of upgraded suspension system on the front and rear. (I'm still learning about the best price/performance tradeoff for what I will purchase for my driving style, which is moderately aggressive city and highway driving.) So as of yet, I have no firm decision on the shocks and coil/spring choice. I know there is a wealth of info here on that.

I was going to attempt to replace as much as I can at the same time, since the ball joint is failing and since stock control arm bushings are better replaced at this point, given my research on this site and on other sites.

The Bentley manual tells me that the ball joints are not replaceable because they are pressed into the aluminum control arm, so I assume I have to replace them, since my ball joint is failing, and would do so as a set on both sides. (I recently saw a post about a control arm aftermarket part with replaceable bearings, but I don't see the benefit to my situation.)

QUESTION: Also, am I missing any other major component of a front suspension upgrade that should be considered in good practice to replace?

Here is my list of intended replacement/upgrades for the front suspension:
  1. Struts and Springs
  2. Front Shock Mounts
  3. Both Control Arms
  4. Control Arm Bushings
  5. Inner Ball Joints? - I might as well replace these, I am thinking....

I'm intending to get an alignment after all of this, too.

Thanks for reading through my post andfor your reply.
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Old 06-29-2008, 04:00 PM   #2
edisapimp
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i was hoping someone would reply to this thread. maybe if you post in a different forum?
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Old 06-29-2008, 11:10 PM   #3
doit659
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I've figured it out ...

I reviewed some posts that were related but not directly on point, looked in the Bentley Manual, checked out some other sites, and looked up parts online.

Basically, at 100,000 miles the entire suspension is pretty tired. If the front and/or rear parts aren't failing, then they will sooner than later.

One poor soul on here replaced each failing part as it failed until he ended up replacing everything within a few months. So, to prevent having to get under the car multiple times and unbolting related systems multiple times, I would recommend the following approach.

In general, I do not recommend replacing any of these parts with OEM components, or you are risking being in the same situation as soon as 30,000 miles in a worst case scenario and having failures with increasing likelihood around 50,000 miles.

Plus, the aftermarket components do offer increased performance, although you do have to pay for it!

FRONT SUSPENSION

1. Struts and Springs - Definitely replace as a set.

The only limit on what to spend here is your budget. Although you can find overlap in all three of these categories, the least expensive route is separate shocks and struts, next cupkits, and finally coilovers. And even in these three categories, you need to determine the stiffness you want to achieve. Racing suspension is pretty much avoided by average motorists on this site because of the jarring ride over extended trips, while street performance products offer a good compromise over a pure street design.

The risk in separate shocks and struts is that the components haven't been necessarily engineered together, so you might experience less than optimal handling because of it. Of course, you might not even notice any problem in handling, esp. if you have a knowledgeable salesman pairing up the components, but more performance orientated drivers don't even take the risk and want more tuning options to the suspension anyway, which is offered by the other two options.

Cupkits are a type of integrated shock/spring that has been engineered together, and offer the option to lower the car frame closer to the wheels. People like this because it enhances performance in steering maneuvers, such as cornering. The actual reduction is pretty minimal, measuring less than 2", but offers a noticeable change in performance, esp. at high speeds. The reason most people prefer coilovers to cupkits is that the height for coilovers can be adjusted while cupkits are fixed. Too low a fit with a cupkit would cause either a harsh ride or problems with speed bumps. Plus, the more expensive coilovers have additional adjustments, such as dampening.

Like cupkits, coilovers integrate the spring onto the strut and offer vertical adjustment of the frame over the wheel. More expensive coilovers have even more adjustments, such as dampening I believe affects the shock's reaction to various road bumps. This site has many threads on what people do with these settings, but most folks set the dampening once and forget it. More avid drivers toy around with these settings when they want different ride characteristics.

Also research this site if you have oversized tires on your car. Although outside of the scope of this thread, I think I remember reading a thread stating that oversized rims and tires can impact the ability to take advantage of some of the more advanced strut adjustments or even the selection of certain strut/coil combinations.

If you go the adjustable route, be aware that coilovers vary in their ability to be easily adjusted. I think I saw one thread where a guy was putting an automated adjuster on his dashboard for custom settings, while more traditional adjustments require the tires being jacked up and then the change being made. There are even more exotic shocks that have more specific tuning capabilities, but that is beyond the scope of this thread, since those coilover sets are well over $1500 for a set of four.

There is another issue if you drive in winter conditions where salt is used on the roads. Some people recommend sticking to manufacturers who use stainless steel rams in their struts as opposed to alloys or galvanized steel. Supposedly, the road salts eat away at the struts prematurely, although manufacturers of non-stainless steel claim that their struts will not suffer from this degradation if maintained properly. But since I'm in Chicago, salt is a major issue, I'm going to play it safe and try to find a stainless steel strut instead of a painted one. But the higher cost of the stainless option may price me out of this option.


2. Front Strut Mounts - Optional replacement.

A lot of people just use their existing mounting hardware if it doesn't show any visible signs of wear or damage. Some people upgrade this component to a "lifetime" mount. But I imagine they are doing so because they are putting their suspension under higher than normal stress and have either broken them in the past or want to remove the risk in the future.

3. Control Arms - Definitely replace as a set.

Control arms have two bushings in them that are prone to wear out in BMW's prematurely, but also wear out in the most vehicles by 100,000 miles. In my case, one of the bushings is leaking oil. The others will follow, I'm sure. Replacing the bushings in the control arms is not possible except for the home mechanic with extensive tooling because the bushings are pressed into the control arm with special tools.

If a home mechanic has a good relationship with a shop or the tools at home, I suppose they can do so themselves for just the cost of the bushings and labor of a shop to remove the old bushings and press new ones. But most guys replace the whole control arm with the bushings integrated.

As a result, most home mechanics simply replace the entire control arm with the bushings already pressed in. Some go the further step of getting control arms where the bushings can be replaced without pressing them in the event that they fail in the future. Not surprisingly, this enhancement comes with a higher priced control arm.

4. Control Arm Bushings - Definitely replace as a set.

These are rubberized bushings inside a metal mount that connect the front control arm to the car frame. These are common areas of premature wear and will result in problems in the suspension performance.

Even BMW supplies an upgraded OEM part for this replacement, but there are other options. Some guys go with a polyurethane bushing with supposed superior life while a small number of people have had problems with this type. Some people think the problems are related to improper installation. As a result, some people just buy a better aftermarket bushing than even the upgraded OEM versions from BMW.

Not installing the control arm bushing with the proper lubricant (usu. soap and water) and at the proper depth will greater reduce their life and may explain the problems experienced by some polyurethane installations.

5. Inner Ball Joints - Replaced as part of the control arm replacement, since it is pressed into the control arm.

Well, that's about it for the suspension system itself. Given the cost of tires for my BMW, I would take the additional precaution of a front end alignment after replacing all of these parts.

REAR SUSPENSION

1. Coils And Shocks - Definitely replace as a set.

Coilover sets for the E46 chassis are technically not coilovers on the rear. Instead, the rears have the spring and shock as separately installed items, much like stock BMW shocks and springs. (Other cars can have true rear coilovers, but I haven't seen them for the E46.)

But even the matched coilover sets, such as the highly regarded Bilstein PSS9 coilover kit, are sold as "coilover" kits even though the rear coil spring and shock are actually not one piece, like a true coilover. Of course, the fronts are true coilovers.

2. Rear Shock Mounts - Optional. See Front Shock Mount discussion, above.

3. Rear Control Arm Inner and Outer Bushings - Replace only if necessary.

The rear trailing arm bushings do not have the same level of premature wear that the OEM front bushings seem to show. However, they may wear out after 100,000 miles. Unfortunately, they are usually seized and difficult to unbolt. Then, you have to rent a special tool to press out the bushings and replace them. (The tool can be rented at a local auto parts store, usually for free by just holding a deposit on the tool. This is different than the pressing needed for the front bushings, but still is somewhat tricky, as I've read.)

More aggressive, DIYers will tackle these preventative repairs or necessary repairs, but even some pretty talented DIYers will still leave these replacements to the pros. Also, the Bentley manual recommends a rear wheel alignment after these replacements.

OTHER RELATED COMPONENTS

Wheel Bearings - These no maintenance parts are only replaced when failure occurs, as far as I've seen. Also, they require some specialized tools usually not found in the home mechanic's toolbox.

Stabilizer Arms - Some high performance owners upgrade these components for performance reasons as part of an extensive suspension upgrades. Otherwise, these are usually not replaced unless damaged for a more conservative suspension upgrade.

CONCLUSION

This site has excellent DIY articles and numerous threads on the actual steps and gotchas with all of these replacements.

In terms of brands and sellers, there are numerous options, and I haven't concluded on what exact brands I will purchase. My decision will be tempered based upon price constraints. Thus, for example, I may pay a little more for coilovers but not spend as much on control arms that have replaceable bushings or replace the shock mounts unless damaged. Also, I am uncertain if the rear control arm trailing bushings are in need of repair or if I would even tackle them if they were.

Although there is not unanimous agreement, some highly regarded suspension kits are Bilstein PSS9 or PSS10 coilover kits, and many from H&R, Eibach and Koni. These are pricey; starting at $1500 and going much higher, but even a good shock/spring replacement set will start at minimum of $800.

Control arms are at least $100 each going up to $300+ for higher performance versions. Meyle German control arms get good reviews and are reasonably priced. The control arm bushing adds about $15+ each (two needed) for cheap (not recommended) replacements up to $80+ for better quality replacements, such as the polyurethane versions. Powerflex is one such brand.

I can't yet tell you which is the best price for any of these components, but they do seem to vary among the online vendors.
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Old 07-02-2008, 10:31 AM   #4
330ci_droptop
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R/F lower control arm's outer ball joint and a broken left rear spring.

This exact same thing happened to my 330ci convertible... i just got the right front side control arm replaced and the left rear spring replaced.. nothing as a set and it seems fine..

but i am still getting a whirring noise, we 1st thought that the ball joint was causing this but its still occuring.. do you think its maybe a bearing? it happens when we ride at 30 - 35mph.. it used to happen at 60mph.. any idea's ?
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Old 07-02-2008, 07:13 PM   #5
Tom Busby
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At about 100,000 miles, 1 and 1/2 years ago, on my 2001 325i, I replaced my stock suspension with Koni FSD (frequency specific damping) struts/shocks and OEM "sport" springs at all four corners. It is very nice. The DTC engages less, so I can confirm that the tires are actually hooking up much better.

The guy above pretty much nailed it but I disagree about OEM vs aftermarket. It just depends on the actual parts at issue. And mainly, I have NOT liked polyeurethane bushings on any street car because of NVH problems, at least IMO.

Here are some other points where I differ slightly with the previous guy:

(1) You don't need to replace the strut mounts in the front unless they are bent, so that the 3 bolts don't all point in the same direction. If you haven't raced the car, and don't plan on it, save your money. I replaced mine needlessly, and spent $440 I shouldn't have.

(2) However you must replace the shock mounts in the back. These are cheap and easy.

(3) You also do NOT need to replace the sway bar endlink bushings, but you do need to replace the sway bar D-bushings. (Front and back, on the chassis, holds each sway bar at 2 points to the chassis)

(4) You should replace the tie rod ends (outer only, there is no inner tie rod end). BMW doesn't stock these any more. NAPA sells them for about $90 the pair.

The rear suspension is complicated to visualize until you start taking it apart. (5) It is absolutely necessary to replace the outer bushing on (rear) upper control arm. (This bushing is right behind the brake rotor, on top.) You can press each old one out with a free-to-rent- Autozone ball joint press and a combination of large and larger sockets in about 20 minutes. Oil the new one and press it in with a socket. You have to remove the wheel, caliper, caliper bracket, and rotor. Don't replace the inner bushing. Don't even unbolt any of the inner bushings on the top or the bottom (rear) control arms.

(6) It may be necessary to replace the front bushing on the rear trailing arm. (This is on the chassis, behind the rear door.) This the one everyone talks about but IMO it doesn't wear out as fast as everyone says it does, unless you race, in which case, it needed replacing yesterday.

(7) Do not replace any bushings on the (rear) lower control arm. (This piece is right behind each rear brake rotor, on the bottom, and it connects to the lower sub-chassis near the differential.) This metal bar is so flexible that the metal moves more than the bushings so nothing really wears out. But if the bar is bent replace the whole thing, bushings included.

This is a fair amount of work for a diy'er. Good luck!

Pay very close attention to how the front spring pads are aligned on the spring perch, on the front strut. Take a picture or make a drawing. These are contrary to logic, and seem to cause people alot of grief.
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Old 07-02-2008, 09:25 PM   #6
doit659
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330ci_DropTop,

Maybe someone else may had experience with your "whirring noise", but my guess is that it is not related to the control arms, which I would think would give more a "clanking" noise on rough roads or irregular steering.

If the whirring noise only occurs while moving and never while idling in park with the engine revved, then I think any other pump bearing on vehicle, such as the fuel pump, may be less likely while the wheel bearing may be ruled in as more likely the origin.

Maybe you can determine if the noise is isolated to one wheel. Sometimes driving with the windows down on a road or lot parallel to a stationary structure, like a building or concrete railing, makes locating the origin more obvious.

Tom,

Thank you for adding your experience to a job that I have yet to undertake!

I'm going to follow your advice on the suggestions you make, although I see myself taking a bit more time with this project with the new replacements that you recommend.

A couple of questions:

1. What are "NVH" problems with the polyurethane bushings?

2. Further research after my post led me to understand that the rear shock mount (RSM) needs an upgrade. What do you recommend?

BMW offers a reinforcement plate, and other aftermarket sources offer more extensive solutions. (I am NOT going to push the suspension other than moderately aggressive city and highway driving.)

Thanks in advance!
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Old 07-03-2008, 02:16 AM   #7
330ci_droptop
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Quote:
Originally Posted by doit659 View Post
330ci_DropTop,

Maybe someone else may had experience with your "whirring noise", but my guess is that it is not related to the control arms, which I would think would give more a "clanking" noise on rough roads or irregular steering.

If the whirring noise only occurs while moving and never while idling in park with the engine revved, then I think any other pump bearing on vehicle, such as the fuel pump, may be less likely while the wheel bearing may be ruled in as more likely the origin.

Maybe you can determine if the noise is isolated to one wheel. Sometimes driving with the windows down on a road or lot parallel to a stationary structure, like a building or concrete railing, makes locating the origin more obvious.

Tom,

Thank you for adding your experience to a job that I have yet to undertake!

I'm going to follow your advice on the suggestions you make, although I see myself taking a bit more time with this project with the new replacements that you recommend.

A couple of questions:

1. What are "NVH" problems with the polyurethane bushings?

2. Further research after my post led me to understand that the rear shock mount (RSM) needs an upgrade. What do you recommend?

BMW offers a reinforcement plate, and other aftermarket sources offer more extensive solutions. (I am NOT going to push the suspension other than moderately aggressive city and highway driving.)

Thanks in advance!


hi
thank you for the advice..

well the noise does not happen when its idle, it happens when i start to drive.. i noticed it actually starts to whir when i am going around 35 mph then if i go a bit faster or slower it seems to stop but then again it happens again at around 70 mph.. i am guessing it is the wheel bearing but i have no clue about things like this to be honest..

and tha clanking noise was coming from the car before but has stopped since i have replaced the front control arm and the rear broken spring... but i am hearing a really high pitched sound like metal is being scrapped together sometimes now?

i knew i should have gone to a bmw specilist and not a normal cheap mechanic
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Old 07-03-2008, 08:28 AM   #8
guitar_man
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These guys are right on

I have replaced a good bit in my front and rear suspension minus steering knuckles, upper rear control arms and rear trailing arms. I did the work myself and I enjoyed it while learning a lot about my car's suspension. The guys who have already posted have given you great input. I agree with Tom on the urethane bushings. I put them in the control arm bushings and the rear trailing arms. In the future I would probably leave them off the front and put the heavy duty rubber control arm bushings instead. For a daily road driver urethane is too hard up front, although I like the rear because it holds toe well. I also put Koni sports with Eibach springs. I probably would go with a "soft sport" spring and something like the Koni FSD dampers. I would still put the biggest sway bars I could fit though. This is subjective based on what kind of ride you are looking for.

The other info they have given you is great advice on what are necessary items to replace. Depending on how much you want to spend, some of it makes sense to replace since you are already going to be in there. At 100K you won't necessarily do yourself any harm by replacing any joint or rubber component.

Don't be afraid of doing the work yourself. It may be a pain and time consuming, but if you enjoy your car (and you probably do since you are here) it will be good knowledge gained. There are great DIY articles here and all of the members I have exchanged with have been very helpful.

I can't add much to what these guys put up I just wanted to post my encouragement to you.

J
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