Sounds From the Rear: Explained

I read through the initial post on this and did not find what I was looking for. I will read the entire post but thought I would try this also. I purchased a 1997 328is for a daily driver and my son to use a D/E events. Since the car was 12 plus years old when we got it, I knew we would be fixing/upgrading as we found things out. I went down to CMP this weekend and only put in two laps. Under hard cornering I would get a bang from the rear. It would only happen once and then no noise or steering issues that I could feel. I would say that it is near max lateral or g force in the turn. Rather than risk any damage I called it a day and proceeded to see if I could find the issue. I have the rear interior out of the car so you get a pretty good feeling of where the sound comes from. Left rear between the dif and the hub. I just had my end links replaced. They were seized up and we thought that was the culprit. After removing the rear wheel we check for bearing play and found none. The consensus was the the bushings may need replacing. I am sure they are all original. I crawled around underneath today and didn't find anything else that I could see. Since it is almost impossible to tell if the bushing is shot without dropping the rear end I am going to start with the assumption that it is. Any help is appreciated!
Jay

Well im hearing this sound almost like it's from my exhaust on my e36 318is automatic whenever the gear shifts up and only for a second i hear a almost like a gurgling noise im pretty sure its my exhaust but i thought i'd check

Originally Posted by ZeGerman

You can always pull back the trunk lining to see the state of your rear shock mounts.

What exactly should I look for in the shock mounts? Will it be obvious that it is broken?

Basically just look to see if the rubber bushing on the shock mount has any apparent damage.

Thanks, great info.

Just an update on what my noise was. We are upgrading the entire rear suspension. Found a bad outer cv on the left side. The noise was coming from the lower ball joint bolt. Number 10 in this diagram:
http://www.realoem.com/bmw/showparts...04&hg=33&fg=30 If I have this correct the 328 has a bushing but you can upgrade to the ball joint used on the M3. Since this car will be tracked by all of us in the family we opted for the kit from Turner and reinforcement plates all around. More than I wanted to spend but piece of mind is priceless when you hit the power in the corners.

So i have a noise coming from the passenger side rear. It sounds like someone trying to "click" an electronic lighter. The faster i go the faster the "clicking" gets. I believe its the RWB any ideas would be great.

If you have a decent jack you can try this.

Chock front wheel, car in neutral, place jack under rear of car and lift slightly. Turn the wheel by hand and listen for your issue. CV joint will give you a clicking sound. If you need a new half shaft let us know. From dealer @ $500 a pop. Used or rebuilt much cheaper.

I have a metallic squeak from the right rear when I go over bumps... but only when it is dry outside. It's been raining here the past few days and haven't heard it at all, but when it's dry outside, I hear it over every bump. With what I've read, it looks like it may be the RSM, and at the price for new ones, was going to replace and reinforce anyway. Does this sound like a likely culprit, or should I be looking at new shocks/springs as well?

Originally Posted by fatmurphy

I have a metallic squeak from the right rear when I go over bumps... but only when it is dry outside. It's been raining here the past few days and haven't heard it at all, but when it's dry outside, I hear it over every bump. With what I've read, it looks like it may be the RSM, and at the price for new ones, was going to replace and reinforce anyway. Does this sound like a likely culprit, or should I be looking at new shocks/springs as well?

I would start with just replacing the RSMs. That is probably the most likely culprit.

Cool, thanks.

Yup, they're a highly common failure point on E36's.

Originally Posted by SCANDINAVIAN13

I think I've gone through pretty much all of the problems you can have with the rear end of the car that will make distinctive noises, so I'm going to lay some of them out for anyone who has problems in the future.

I'll start with the most severe:

My car sounds like...

...a helicopter:
Pull over now!!! The most probable cause of the sound is one or several loose lugs. Stop the car, bust out the BMW tool kit (the tire iron is actually over on the battery cover) and tighten all of the offending lugs. While you're at it, go ahead and check all of the rest of the lugs too. If the lugs work their way out far enough, the sound will get worse and the shaking will pick up. Eventually the lugs will snap and you'll note you'll be riding a bit lower on that side. By then, it's generally a bit too late - your car's on the ground.

...it has metal scraping around in back:
It might be that the rear shock mount (RSM) has failed. This failure, however might not have occurred at the shock mount itself, unfortunately. The metal scraping and knocking could mean the failure occurred at the frame mount. This is going to require some metal work to fix. Plan on spending a good amount on fixing it.
To prevent this, upgrade your shock mounts and re-enforce them! Re-enforcement plates are available at BavAuto, among other BMW parts shops.

...there's a slight knocking or squeak in back:
As mentioned above, there is probably a problem with the RSM. A knock means that the RSM has probably failed and the upper mount of the shock is just knocking around freely. Squeaking generally only occurs when the roads are wet, but can occur at other times, and generally means the same thing. Both the knocking and squeaking should co-incide with suspension actions, such as driving over bumps, or rough roads. This problem isn't as urgent as the above-mentioned, but since the mount has failed, it's possible that moisture can now get into the car, which can cause other problems. Get new rear shock mounts. Meyle makes a heavy-duty RSM that resists push through failures (most common type), yet retains the stock feel, unlike many of the urethane upgrades. If you're going performance, now is a good time to upgrade to urethane. When you replace the shock mounts, don't forget to buy a re-enforcement plate! Replacement RSMs are available at most all BMW part shops, and re-enforcement plates can be found at BavAuto, and maybe Pelican.

...it's running on off-road tires:
This is most likely a failure of the rear wheel bearing (RWB). The rear wheel bearing failure's sound can range from a grumble, to a growl, to a roar. When it gets bad, it will sound like you're riding in a Jeep with huge off-road tires. The sound will follow your car's speed, not the engine RPM. Generally, as you get faster, the sound gets louder. This is not always the case, however, as sometimes there is a point at which the sound will die down some. To check the speed correlation, bring the car up to highway speed and press the clutch pedal (if you're an AT, put the car in N - this is illegal in many states, so watch yourself) to let the engine spool down to idle, while your speed remains relatively high. If the sound remains strong, it's most likely the bearing. If the sound dies with the engine RPM, you've got something else wrong.
RWB fixes are nasty! They aren't super-urgent, but be aware that if the bearing finally fails completely and locks, you're not going to be getting anywhere very quickly and you'll probably need to replace the tire that just got dragged until you stopped. I drove on mine for a while before I replaced it; some 4,000mi, I think. That's not the smartest option, but I needed to save up for the parts and tool.

DIY GUYS: This fix is time-consuming and expensive! The tool to remove and press the bearings is around $250 itself. The bearings are around $30 each. If you have a while (and the patience!!) to do this job, this is your best option. You can do both bearings on the rear axle for the price of what most garages charge for one. Expect hang-ups if your car has not had much service in the rear. Frozen bolts, hubs and rotors all slow progress and are a general pain. Once you get it done, however, your car will sound like new again. The tool and parts are available at Pelican Parts (they have the best prices on this job, believe you me!).
You will need:
2 RWBs, 2 Circlips, 2 New Rotor Screws (one-use part, don't re-use the old one!) and the bearing press. A Bentley Manual is an absolute must! If you don't have one, PM me and I'll send you my write-up with alternatives, should one of the options not work.

NON-DIY GUYS: This fix is expensive! Expect the shop to charge around $300-350 (that's at independent shops). It will be a bit less on the second bearing if you're getting both done. BE AWARE that some BMW specialty shops may try and screw you. One BMW shop that I trusted quoted me at 7 hours of labour, plus over-priced parts, so watch yourself. I could've gotten the job done in 1 hour a side if I had a lift and shop tools. Seven is about what it took me in the end with socket wrenches, jack stands and a rubber mallet.

...it's hissing:
First, check and make sure you don't have a hole in your tires. If that's not the case, and it sounds more sandpaper-ish than high-pressure air, then it's probably something rubbing. More specifically, the brake rotor shields. If it's very light-sounding, it's probably fine. If it's more gouging or metallic-sounding, you should probably try to re-bend the shield so it's not rubbing so intensely. The best bet, however is just getting them replaced. The shields themselves are not too expensive, but the job is similar to the rear wheel bearing job, as the rotor will need to be removed and the hub will need to be pressed off to get to the brake shield. I haven't gotten a quote from a shop, but I'd expect labour to be the main cost in this fix.


I hope this clears up some of your sound worries. Good luck with the fixes!

Sticky, if I could re rate this post and it was possible to give 10 stars, not just 5, I would ! Outstanding. Read it, called my mechanic (car is there for tail light fix and door actuator) and told him to raise 'er up and take a look at the RSM's. That sounds exactly like what I hear coming from the rear end of the car when i drive it over even mildly uneven or bumpy roads. Depending on what they find, I suppose it could always be something else, but this is a great first check. Thanks !

Technically Challenged

so my car has issues and im working them all out... the one im focusing on now is this high pitch squeal it makes when it shifts. it only does it if im pushing it hard and it shifts hard. i took a look below and noticed my flex plate is a little frayed and im looking into getting another one. would the rubber be rubbing and forcing the squeal. also could that mean my tranny mounts are bad cause its moving when it shifts and then the flex disc is rubbing against something?

please help...

Hi everyone. This is my fisrt time here so be gentle with me. I have a question which I'm hoping someone can help me with. I have a 1997 e36 323i 2.5 coupe, and when I am stationary and depress the clutch to pull away everything is fine, but when I place it into first gear the is a clunk noise from what sounds like the rear. Any thoughts. Many thanks.

An update. It does it mostly when changing up gear too even if done gently. Thanks.

At least you came to the right place. And where exactly is the noise coming from? You need to pinpoint it.

It's hard to pinpoint but it could be centre rear or towards the passenger side rear. As it happens sometimes when stationary im guessing it's drive train related???

It might be your diff bolts. They like to come loose on E36 M3's, give it a check and maybe take some pictures?

It could also be a cracked subframe.

Cracked sub frame????? That sounds bad. I'm going to hope its the diff part as loose bolts I can handle. Lol I will check the propshaft bolts too if that's the case. Will look in the morning and will post what I find. Many thanks.

I has the same issue, and I know my diff bushings are shot. Im gonna start there and see if it makes a difference. How are your diff bushings?

I only found out to look at that area today and as it's late now, I will look at it tomorrow and post my findings.

Not sure if anyone had this one before...and I didn't read all the topics since it's 5 pages! But when the car is on heavy load (3-5 people) theres a kind of weird buzzing noise from under the car (drive shaft...) Only when theres weight. I had the hanger bearing changed and my disk changed too (the big thingy that connext the transmission and the drive shaft. Could it be anything else?

Well, you do have a couple of universal joints in the drive shaft.

Describe "buzzing".

Hmmm like a vroom vroom vroom vroom lol it's just weird...its not like a place or something like that! It only happens when at low speed and in demand of power...if press the gaz hard enough. The rest of the time it's fine. Almost as if it wasn't straight (the drive shaft)