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Discussion Starter · #1 · (Edited)
Hi all,

I've been searching and reading up on all the DIY notes on replacing the rear shocks and mounts. 2000 328i sport/premium, 133k..

I'm contemplating replacing my original sport suspension with another OEM sport suspension (car has 133k and still using original...). I'm a casual driver, and although I do occasional aggressive maneuvers (like, avoiding hitting a couch at 75mph that was dropped in front of my car on a freeway, for instance. Boy was I glad I was in my 328i... not sure if the car behind me missed it though, but I was so full of adrenaline I didn't think to stop and check..) but for the most part, I've been happy with OEM suspension, so thought I'd just go get a new one.

Anyway, I'll get the pro to do the front shocks since it looks complicated, and requires alignment anyway and I can't do that. but to save $$, I've been pondering if it really is that easy to replace OEM sport rear shocks with a new one, I'd thought I'd try it.

But I have a hard time believing it's that easy.. jack up the car, put it on jack stands, remove the trunk lining, unbolt a nut or two, go to underside, unscrew few nuts/bolts.. take out the old one, put in a new one, and re-screw everything together (and replace the shock mounts while I'm at it with the reinforcement plate).

If the work is really that easy, I'm willing to try (I'm 5'2" female.. very mechanically/engineering inclined, but no means an expert). I've replaced speakers, spark plugs, and other more electrical-related things, but nothing mechanical before.

so.. is there a catch? Is it really just screw-off/screw-on/torque wrench it and done? I keep reading about compressing springs.. is this just for upgrades using aftermarket parts and for front shocks?

Thanks for any reassurance you can give...
 

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Take the thing apart and find out! I did some performance suspension on a 325, it wasn't all that bad. The shocks in the rear were the easiest part. The front was the next easiest part, the adjustable rear control arms were the hardest. I can't remember what the front had for stock - I installed some camber plates and thus aligned it afterwards. You can easily remove the front and reinstall, then take it to the alignment rack and save yourself the money on install time.

Seth
 

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Discussion Starter · #4 ·
Wow. Ok. I'll definitely do the rear myself. I'm still a bit weary about the front though. What is all the talk on compressing springs in the front? it sounds mildly dangerous if you let it unspring at an inopportune time..

Also, I presume it's not a good idea to mix different shock manufacturers for front/rear, correct? if I go OEM on front, i should stay OEM on the rear? If there is an aftermarket shocks for the rear that rides similarly as the OEM sport, and has better longevity, I'm open to it. One of the mechanics suggested Bilstein shocks for quality and KYB for getting parts cheaper...

I just don't want it going lower than it already is (I already have to go over this one speed bump at a parking lot at almost zero speed because any bounce of the car as it rides off the bump, will scrape the bottom.. of the car).
 

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your springs will generally control the height and the shocks will control the springs. There is a complete scinece behind this. If you want to know more, look into control theory.

If you are removing and replacing the springs, you'll need a spring compressor. The one from autozone actually works pretty well. It is a scary task, and you should only try if you have lots of courage. There is a lot of stored energy in a compressed car spring, and if it lets loose (which I have seen), it can be destructive.
 

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Discussion Starter · #6 ·
Hi,

thanks for all the inputs. I guess now I will go study the front suspension replacement DIY and see if it's something that is within my capability :) I've been focusing on the rear only, so to the search box I go...

Nice to have cars that seem to be relatively easily DIY-able.

Thanks!
 

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It's almost that easy. After removing the trunk liner, also need to remove the soundproofing matting over the rear shock mounts, at least in the sedan. It's not difficult, just a hassle. To get it out intact you have to remove the amp/nav holder on the left (about 6 small nuts) and a wire junction box on the right. In my case the sound matting still tore and I taped it back together with duct tape before reinstalling it. The next time I'll just cut out a square of sound absorbent matting above each rear shock mount.

It might help to put a jack beneath the bottom of the rear shock when you're taking it out and putting it back in, so you can lower the rear suspension slowly when removing old shock and raise it up to the right level when connecting the new shock.

If you do front yourself, there are a few considerations. If you have the self-leveling Xenon lights, disconnect the suspension level sensor, which is on only one side (I think front left and rear right?). The strut assembly is heavier than the back because it has strut, spring, spring mounts, and strut mount together. You will be able to lift the strut assembly easily when it's out of the car, but it can be difficult to raise the new one into place properly because you're trying to lift it and align it with the tower holes at the same time. Much easier if you have someone helping you--one person lifts the strut and the other either guides it into place or puts the nuts on the mount studs so it doesn't fall back down. And you can rent a spring compressor from most AutoZone or Kragen/O'reilly.

(Edit: Need to unbolt swaybar links from strut before removing strut. This requires both a socket and an open-ended wrench (probably 16mm). I don't remember if I bolted the strut bottom into the knuckle first then raised the whole suspension into position with a jack, or if I first loosely bolted the strut into the strut tower up top then raised the knuckle/hub/rotor with a jack. In either case, when the front strut is out, the knuckle wants to flop around because of the weight of the brake caliper and rotor. Use a wire coathanger or elastic bunji cord with hooks to hook it to something so the brake hose isn't supporting the whole weight of the thing while you're moving the spring to the new strut.)

You don't need an alignment after replacing front struts if your use stock strut mounts in stock location, because the caster is not adjustable and the camber is fixed by a locating pin. And toe is controlled by your tie-rods, not the struts.

it's that easy.
 

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Op said he would jack the car up. However, I did my two rear shocks without jacking anything.

Sent from my SAMSUNG-SGH-I896 using Bimmer App
 
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^^^this, it's not necessary to jack the car up, but it makes life a little easier as it takes off strain off the lower bolt to the trailing arm.
 

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Removing and installing tthe spring was the worst part for me and they weren't that bad so if your not touching them you'll be fine. The hardest part is honestly probably stripping the trunk, which I had done before so it was a breeze. Definitely an easy DIY and do yourself a favor and get Rogue Engineering RSM's. You'll never have to strip the trunk again to remove the shock, they don't make noise like most aftermarket shock mounts and are completely rebuildable. Just my .02!
 

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The rear is really that easy.

The front is more involved. Start in the back and see how you feel about it. I have been working on cars for awhile, and I am still very cautious when it comes to struts.
 

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Discussion Starter · #13 ·
Op said he would jack the car up. However, I did my two rear shocks without jacking anything.
how can you do this? wouldn't the weight of the car press down on it enough that it will make it virtually impossible to remove the rear shocks? Or under neutral condition, there's no stress on the shocks? (yeah.. I know.. I'm exposing my lack of knowledge here...). I guess on the rear the spring is separate so the spring keeps the rear from collapsing?
 

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Discussion Starter · #14 ·
Removing and installing tthe spring was the worst part for me and they weren't that bad so if your not touching them you'll be fine. The hardest part is honestly probably stripping the trunk, which I had done before so it was a breeze. Definitely an easy DIY and do yourself a favor and get Rogue Engineering RSM's. You'll never have to strip the trunk again to remove the shock, they don't make noise like most aftermarket shock mounts and are completely rebuildable. Just my .02!
I will look into this. I was planning on OEM mounts. I read up enough to get the metal bracket on topside to help support the bolts, so I was planning on getting that too. thanks!
 

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Discussion Starter · #15 · (Edited)
It's almost that easy...

If you do front yourself, there are a few considerations. If you have the self-leveling Xenon lights, disconnect the suspension level sensor, which is on only one side (I think front left and rear right?). The strut assembly is heavier than the back because it has strut, spring, spring mounts, and strut mount together. You will be able to lift the strut assembly easily when it's out of the car, but it can be difficult to raise the new one into place properly because you're trying to lift it and align it with the tower holes at the same time. Much easier if you have someone helping you--one person lifts the strut and the other either guides it into place or puts the nuts on the mount studs so it doesn't fall back down. And you can rent a spring compressor from most AutoZone or Kragen/O'reilly.

(snip)

You don't need an alignment after replacing front struts if your use stock strut mounts in stock location, because the caster is not adjustable and the camber is fixed by a locating pin. And toe is controlled by your tie-rods, not the struts.
I do have Xenon. hm. front does sound more involved (if not heavy). I will do the rear and see how much I can man-handle the thing first.. then contemplate the front. but from the sounds of it, it might be a teeny bit scary for me to do the front.

Good to know about the alignment. I just got 4 new tires and got 4-wheel alignment, so wasn't too keen on having to do another alignment--this is another long story... short version is that I got Meyle HD CA and CAB replaced, got 4 new tires-Conti Extreme DWS, and got 4 wheel aligned. in 6mo/6000mi, the two front tires no longer have inside tread, and I don't drive that hard... front inner tread is wore down to the wear bar!

the tire installer is blaming the suspension, that it had coincidentally failed right at the same time they replaced the tires, nistalled CA/CAB and did alignment. I'm a bit skeptic about that explanation since my trusty BMW specialist mechanic had just checked the car (and they have been keeping an eye on a small crack in the rear mount, so... they are very thorough, so they would have noticed that suspension is that bad) 1mo prior to tire install, and the car just got thoroughly checked by BMW dealer for the subframe suit thing. and believe me, with the age of the car, they looked thoroughly to make sure they don't miss an opportunity to make more repair recommendations. got none.

I think excessive uneven tire wear was caused by poor alignment, but what do I know. I did get a printout of the measurements, and some are few 0.01's off. installer wanted to brush it off as "it's within the measurement error" but I'm suspicious of that. My usual mechanic wanted me to bring in the measurement data so I'll be doing that too. The old tire that got replaced was worn out but relatively evenly and I got 60k out of it (Pzero Nero. shows what my driving style is, eh?). hard to believe that it would all of a sudden just crash.

But nonetheless, given the age of the suspensions if I have to replace the front, I'll probably need to replace the rear... . I'm taking my car to my trusty BMW specialist mechanic tomorrow to hear what he has to say, but this has made me ponder it may be time to replace the shocks even if that didn't turn out to be the premature tire wear cause... It has been feeling a bit soft for a while now. thus my postings on replacing shocks.
 

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if you post the "after" alignment specs from the shop, that might help diagnose it. They might have put in too much toe-in for the front wheels. Just using the BMW stock toe settings can cause excess tire wear on the inner edges of the tires from a combination of toe-in and negative camber, though I heard that kind of wear usually happens more in the rear tires. Still, post the alignment settings... maybe the shop got degrees and inches mixed up, or degrees and minutes mixed up.

If you can do the back shocks, you can do the front with an assistant, even an assistant who knows nothing about car repair. Oh well you will need that spring compressor, an combo or box-end wrench big enough to fit the top nut on the strut (19mm?), and whatever kind of hex socket fits the end of the strut shaft. But the only two things making the front struts more complex than the rear shocks are
1) Front strut bottom is inserted inside the steering knuckle, which makes the whole thing heavier, which is why you want the assistant
2) The spring is surrounding the strut and must be compressed then moved to the new strut. Not difficult, just needs spring compressor (and the large combo wrench) and needs to be done carefully.
 

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Discussion Starter · #17 ·
if you post the "after" alignment specs from the shop, that might help diagnose it. They might have put in too much toe-in for the front wheels. Just using the BMW stock toe settings can cause excess tire wear on the inner edges of the tires from a combination of toe-in and negative camber, though I heard that kind of wear usually happens more in the rear tires. Still, post the alignment settings... maybe the shop got degrees and inches mixed up, or degrees and minutes mixed up.
the "current" toe value was completely off. strangely enough when I first got it aligned, they never gave me a copy of the alignment data (I was in a hurry.. and didn't look for it when I signed for the receipt). So I went back to the shop.. few times for the original before/after alignment data...

As it turned out, after I REALLY pressed the mechanic shop about my alignment, they produced a really messed-up alignment data for my car. Everything is wrong on that paper... the specs they were supposed to line it up to doesn't match the numbers for my car, doesn't have the right customer number, etc., etc. It was so glaringly for a wrong car, I gave them a chance.. "Please dont' tell me you aligned my car to these specs, because if you did, I mean, that's REALLY bad!"

After much civilized conversation, the owner and the service rep combed through ALL the documents and timestamps, and concluded something went REALLY wrong with the alignment of my car. Either they didn't align my car at all, or they used the wrong car alignment spec to align my car to!

Either way since they don't know what the he** happened, they have offered to buy me two replacement tires and re-align the wheels for free.

they did a quick fix of the front wheel alignment and the steering already feels exponentially better. I also took my car to my BMW specialist to have them look through the shocks and other general suspension conditions, and they said aside from the really bad tire wear on the front, the car looks fine.

So, I'm waiting to get the new tires and full alignment. They are also recalibrating their alignment equipment and upgrading their software so weirdness like this will be unlikely to happen again. I don't know whether to trust their alignment again or not.. so wondering if I should spend more $$ to get the alignment checked at another shop after they install the tires and re-align.

If you can do the back shocks, you can do the front with an assistant, even an assistant who knows nothing about car repair. Oh well you will need that spring compressor, an combo or box-end wrench big enough to fit the top nut on the strut (19mm?), and whatever kind of hex socket fits the end of the strut shaft. But the only two things making the front struts more complex than the rear shocks are
1) Front strut bottom is inserted inside the steering knuckle, which makes the whole thing heavier, which is why you want the assistant
2) The spring is surrounding the strut and must be compressed then moved to the new strut. Not difficult, just needs spring compressor (and the large combo wrench) and needs to be done carefully.
Given my trusty mechanic insisted that despite 133k, there is nothing wrong with my shocks (he even invited me to go under the car and show me that there are no leaks, etc... and the usual "bounce" test is more than satisfactory... I shove the bumper really hard and it just pops right back with no extra rebound), I'll probably just replace the RMTs since it's starting to crack, but leave the shocks as-is... I asked him how I hear many people say that the OEM shocks don't last that long, he said he owns a 2004 E46 at 150k, with original shocks and it's fine.. so...
 

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Discussion Starter · #19 ·
150k(Miles) with original shocks and they r fine? lol
Well, not everybody drives on city streets/freeways like a rally race, so the level of "fine" varies quite a bit (My car is at 133k, but I just did the 90k service at 125k when the inspectionI indicator came on, so... that ought to tell you how my car is not stressed much... and am just replacing to my 3rd set of tires that just got destroyed. yup both the original Conti and the Pzero Nero lasted 60k each. not complaining!) :p

My sports suspension probably does feel more like a standard suspension though. And I'm sure that the car will feel much tighter if I do replace the shocks, but no way to compare how much worse it is now unless I replace the suspension to new ones, and I'm not quite financially ready to spend $550+ on shock components just yet (more if I decide to get the front installed by someone else) when I just spent a bundle replacing CA/CAB, 4 new tires, alignment... Especially when I only drive about 4k/yr these days...

so... as the mechanic says, "it's fine".
 

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So did you replace the rear shocks and RSMs? Was it hard or easy?

Pretty sure my front struts are original with 149,000 miles. Everyone says they were blown by 100K miles, if not by 60K miles, so I assume they are blown, but they're not leaking or creaking and I think the car drives fine. I'm sure the car will handle and ride even better once I replace them, but in balancing spending priorities, I've decided to get a dedicated set of track/AutoX tires before getting new struts. (I replaced rear shocks 15,000 miles ago.)

I do need to take out the front struts to put in some fixed camber plates, so at that time I'll check if they still have any gas charge left in them.
 
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