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      11-10-2011, 10:10 AM   #23
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Quote:
Originally Posted by THE TECH View Post
Make sure your nuts are tight!!
my nuts are as tight as can be

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      11-10-2011, 10:20 AM   #24
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Did this on mine. Took the nuts off. No need to remove the actual bolts, just the nuts. Tighten them back when your reattach the hangers and you'll be fine.

I tightened mine, but these threads recently are making me want to raise it again and just make sure they are tight, lol...
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      11-10-2011, 10:21 AM   #25
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Quote:
Originally Posted by 1sikbmr View Post
correct. The first time I took off my exhaust I removed it by prying it off the hangers shit took me almost 2-1/2 hours to do. the weight of the exhaust makes the hangers even harder to come off so removing the two nuts on the diff is 10x easier. What happens is some people do not place them back on when they are done or do not tighten them enough to not move again. Me personally I tightened it all the way that I possibly could so there could be no room for it to wiggle off. If you forget to put em back on or don't tighten them enough thats where you run into problems.

Perfect. Thank you for your input. I'm a bit anal when it comes to figuring something out, that doesn't make sense to me.
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      11-10-2011, 12:29 PM   #26
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Lets get a couple of the facts straight here in regards to this matter.

The 2 nuts that people undo to remove the rear section brackets DO NOT support or keep the Differential tight and in its place. There are 2 very long BOLTS that go in from the other direction (front of the car going toward the back) into 2 threaded holes on the differential mounting ears.

The 2 18mm Nuts are solely there to hold up the exhaust hanger and do not require much torque to be on them. They are not there to support the differential.

It is proper procedure to undo these two nuts and remove the exhaust system. Using a pry-bar with the exhaust weight on those hangers will damage the hangers.

The exhaust system splits before it reaches the differential (from front to back perspective)

The differential failures people have been having are not a result of these bolts being loose. They are a result of the bolt simply not being strong enough and it shears itself off In some cases, they have found the bolt to "become loose" when the bolt has actually physically stretched out. The differential bolts are threaded all the way through when they should only be threaded where they bolt into the differential mounting ears. There is compliance in axle carrier and it is partly the bushings (which lead to insane amounts of axle hop and torque shock rebound from the highly responsive motor) and lastly the differential mounts on the axle carrier itself. It is not very stout compared to the rest of the subframe, and a couple weld in reinforcement brackets would certainly alleviate much of the problem.

-Malek
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      11-10-2011, 01:16 PM   #27
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Malekreza11 is 100% correct. Great explanation.
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      11-10-2011, 01:25 PM   #28
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Malek - are you saying the front bolts are full-body threaded rather than partial threaded? That's a stupid application if so, wonder why they did that
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      11-10-2011, 03:47 PM   #29
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Quote:
Originally Posted by Malekreza11 View Post
Lets get a couple of the facts straight here in regards to this matter.

The 2 nuts that people undo to remove the rear section brackets DO NOT support or keep the Differential tight and in its place. There are 2 very long BOLTS that go in from the other direction (front of the car going toward the back) into 2 threaded holes on the differential mounting ears.

The 2 18mm Nuts are solely there to hold up the exhaust hanger and do not require much torque to be on them. They are not there to support the differential.

It is proper procedure to undo these two nuts and remove the exhaust system. Using a pry-bar with the exhaust weight on those hangers will damage the hangers.

The exhaust system splits before it reaches the differential (from front to back perspective)

The differential failures people have been having are not a result of these bolts being loose. They are a result of the bolt simply not being strong enough and it shears itself off In some cases, they have found the bolt to "become loose" when the bolt has actually physically stretched out. The differential bolts are threaded all the way through when they should only be threaded where they bolt into the differential mounting ears. There is compliance in axle carrier and it is partly the bushings (which lead to insane amounts of axle hop and torque shock rebound from the highly responsive motor) and lastly the differential mounts on the axle carrier itself. It is not very stout compared to the rest of the subframe, and a couple weld in reinforcement brackets would certainly alleviate much of the problem.

-Malek
Hmm. Thank you. I guess I should have removed the hangers then? So in reality most of these issues are with regard to BMW's design not exhaust installation that removes the hanger?
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      11-10-2011, 04:10 PM   #30
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Quote:
Originally Posted by Richbot View Post
Malek - are you saying the front bolts are full-body threaded rather than partial threaded? That's a stupid application if so, wonder why they did that
Yes the bolt is fully threaded which is pretty dumb because it makes the bolt weaker and far more prone to shearing and stretching. The material of the bolt is rather soft as well. I am working on a subframe reinforcement setup that includes better mounting hardware and weld in reinforcement tabs for the carrier mounts. I will continue to work on this hard.

Quote:
Originally Posted by Rekrul View Post
Hmm. Thank you. I guess I should have removed the hangers then? So in reality most of these issues are with regard to BMW's design not exhaust installation that removes the hanger?
Yes, you should undo the 2 18mm nuts and release the hanger brackets. Those 2 nuts do not require much torque and serve no other purpose other than mounting the hangers. To be clear, they bare no affect on the differential what so ever.

-Malek
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      11-10-2011, 06:37 PM   #31
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Yeah, I have no idea... I put my car on a lift, unbolted the clamps for the exhaust after the resonators, then slipped the hangers out of the rubber bases and it came right out... Never had to touch and diff bolts and it only took 20 min.....
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      11-10-2011, 10:45 PM   #32
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Quote:
Originally Posted by Malekreza11 View Post
Lets get a couple of the facts straight here in regards to this matter.

The 2 nuts that people undo to remove the rear section brackets DO NOT support or keep the Differential tight and in its place. There are 2 very long BOLTS that go in from the other direction (front of the car going toward the back) into 2 threaded holes on the differential mounting ears.

The 2 18mm Nuts are solely there to hold up the exhaust hanger and do not require much torque to be on them. They are not there to support the differential.

It is proper procedure to undo these two nuts and remove the exhaust system. Using a pry-bar with the exhaust weight on those hangers will damage the hangers.

The exhaust system splits before it reaches the differential (from front to back perspective)

The differential failures people have been having are not a result of these bolts being loose. They are a result of the bolt simply not being strong enough and it shears itself off In some cases, they have found the bolt to "become loose" when the bolt has actually physically stretched out. The differential bolts are threaded all the way through when they should only be threaded where they bolt into the differential mounting ears. There is compliance in axle carrier and it is partly the bushings (which lead to insane amounts of axle hop and torque shock rebound from the highly responsive motor) and lastly the differential mounts on the axle carrier itself. It is not very stout compared to the rest of the subframe, and a couple weld in reinforcement brackets would certainly alleviate much of the problem.

-Malek
Great info - thanks!
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      11-11-2011, 01:59 PM   #33
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Quote:
Originally Posted by Templar View Post
Did this on mine. Took the nuts off. No need to remove the actual bolts, just the nuts. Tighten them back when your reattach the hangers and you'll be fine.

I tightened mine, but these threads recently are making me want to raise it again and just make sure they are tight, lol...
There's actually no reason to remove the nuts either. Spray a little WD-40 on the rod that runs through the center of the grommet and gently pry the grommet off (from the pipe side) with a front end fork. You can seriously have both sides done in less than 5 minutes.
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      11-11-2011, 06:38 PM   #34
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Quote:
Originally Posted by Templar View Post
Did this on mine. Took the nuts off. No need to remove the actual bolts, just the nuts. Tighten them back when your reattach the hangers and you'll be fine.

I tightened mine, but these threads recently are making me want to raise it again and just make sure they are tight, lol...
Just use a dab of loctite. My 328i has the same style to hold up the exhaust, noticed one day my exhaust looked lower than normal. Put it up on the lift after work and behold, From the factory the nut started to come loose! Used some loctite and torqued it down. No issues after that.
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      11-13-2011, 11:31 PM   #35
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Quote:
Originally Posted by Malekreza11 View Post
Lets get a couple of the facts straight here in regards to this matter.

The 2 nuts that people undo to remove the rear section brackets DO NOT support or keep the Differential tight and in its place. There are 2 very long BOLTS that go in from the other direction (front of the car going toward the back) into 2 threaded holes on the differential mounting ears.

The 2 18mm Nuts are solely there to hold up the exhaust hanger and do not require much torque to be on them. They are not there to support the differential.

It is proper procedure to undo these two nuts and remove the exhaust system. Using a pry-bar with the exhaust weight on those hangers will damage the hangers.

The exhaust system splits before it reaches the differential (from front to back perspective)

The differential failures people have been having are not a result of these bolts being loose. They are a result of the bolt simply not being strong enough and it shears itself off In some cases, they have found the bolt to "become loose" when the bolt has actually physically stretched out. The differential bolts are threaded all the way through when they should only be threaded where they bolt into the differential mounting ears. There is compliance in axle carrier and it is partly the bushings (which lead to insane amounts of axle hop and torque shock rebound from the highly responsive motor) and lastly the differential mounts on the axle carrier itself. It is not very stout compared to the rest of the subframe, and a couple weld in reinforcement brackets would certainly alleviate much of the problem.

-Malek
Absolutely right. Thanks for that.
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      11-15-2011, 10:33 AM   #36
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Quote:
Originally Posted by Malekreza11 View Post
Yes the bolt is fully threaded which is pretty dumb because it makes the bolt weaker and far more prone to shearing and stretching. The material of the bolt is rather soft as well. I am working on a subframe reinforcement setup that includes better mounting hardware and weld in reinforcement tabs for the carrier mounts. I will continue to work on this hard.



Yes, you should undo the 2 18mm nuts and release the hanger brackets. Those 2 nuts do not require much torque and serve no other purpose other than mounting the hangers. To be clear, they bare no affect on the differential what so ever.

-Malek
After reading your posts it made me feel a lot better. I'm still going to double check, if anything just to make sure the exhaust is on correctly
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