Exhaust hanger bracket question

[ojannen]

I have a 2001 coupe (M54) that has two exhaust hangers for the muffler. The right muffler hanger bracket is no longer attached to the car. I can't find how the bracket is attached to the car on realoem or the bentley manual.

Right now, there is a single machine screw loosely holding it on. I am guessing someone did a quick repair before I owned the car instead of doing it right.

It looks like there are two bolt holes in the bracket and floor pan of the car. Can someone show me a diagram of how the bracket is attached to the car? Should it be welded back on?

[The ZED]

It was welded on but the sheet metal has given way. It just recently happened to mine. I fixed it with a zip tie.

[gmushial]

I don't know if there were major changes btwn 1999 and 2001 and btwn a roadie and a coupe... but this is how they look on my '99 m52tub25 roadie.

front mount:



rear mount:

[ojannen]

The rear mount bracket on the bottom picture is the one that has fallen off the car. Looks like welding it back on is the permanent solution. I am glad I didn't remove the interior of the car.

How would I fix it with a zip tie?

[gmushial]

I don't know if you can really weld it back on, ie, it was only spot welded on to start with - unless that's what you were thinking. But I think I would "locate" it with four sheet metal screws, but would roughen the surfaces on both the bracket and the piece it was originally welded to, and put a good layer of JBweld btwn the two, and then tighten down the screws. Short of that, one could use four or six 1/4-20's or something like that, drill 1/4" holds in the hanger piece, and tap 1/4-20 holes in the supporting piece, add screws and Loctite them in place. Though if I went the JBweld route, I'd be sure to paint over the whole mess in that JB tends to induce rust around the edges, ie, keep the water out and hopefully no rust will form.

[steve f]

The rear muffler support is not a strong point in the build up on the Z3. It is only held in by the two spot welds as you can see by the picture posted by gmushial. That support broke free from the spot welds on my car soon after the warranty expired. Frankly, I'm surprised more people haven't had the same problem.

The rear mount bracket on the bottom picture is the one that has fallen off the car. Looks like welding it back on is the permanent solution. I am glad I didn't remove the interior of the car.

How would I fix it with a zip tie?

Most likely you'll need to remove the bumper so you can gain enough access to weld it back in. That probalby would be the best fix, but I removed the rear most plastic panel from the trunk of my car and through bolted it when I repaired mine. There is plenty of access for that.

I don't know if there were major changes btwn 1999 and 2001 and btwn a roadie and a coupe... but this is how they look on my '99 m52tub25 roadie.

rear mount:

The support should all be similar. From the picture, it looks like both of your spot-welds have broken through on the mount on your car too. Does it rattle?

[gmushial]

The rear muffler support is not a strong point in the build up on the Z3. It is only held in by the two spot welds as you can see by the picture posted by gmushial. That support broke free from the spot welds on my car soon after the warranty expired. Frankly, I'm surprised more people haven't had the same problem.



Most likely you'll need to remove the bumper so you can gain enough access to weld it back in. That probalby would be the best fix, but I removed the rear most plastic panel from the trunk of my car and through bolted it when I repaired mine. There is plenty of access for that.



The support should all be similar. From the picture, it looks like both of your spot-welds have broken through on the mount on your car too. Does it rattle?

No rattle. Actually I think there are four spot welds that hold the bracket in place - two one can see to the right of the raised area, and one can get hints of the two on the left, but barely. But the hanger is rock solid, ie, I did the all the bushings of the RSF + diff mount a month or so ago, and the hanger is not going anywhere anytime soon (especially given the force needed to get the rubber pieces onto the pins - had the whole exhaust system out to do such). I think the two holes one sees were put there by bimmer - to save weight?? - but aren't broken welds.

[ojannen]

I cleaned up the bracket, scuffed it up and jb welded it back into place. Hopefully it will stay there for a while longer.

There are very few forum posts and nothing in repair manuals about this weld failing. When it first happened, I did not see the bad bracket because the spare tire was in the way. In case anyone finds this thread in the future, you might have this problem if you have these two symptoms:

1. Quick metal on metal rattle. This is the sound of the bracket vibrating against the muffler heat shield. It matches the description of a loose parking brake cable
2. Clunking over bumps. This is the sound of the muffler bouncing up and down. It matches the description of failing rear shock mounts.

You are looking at a guy with well adjusted parking brakes and a nice new set of rogue engineering shock mounts.

[gmushial]

I cleaned up the bracket, scuffed it up and jb welded it back into place. Hopefully it will stay there for a while longer.

There are very few forum posts and nothing in repair manuals about this weld failing. When it first happened, I did not see the bad bracket because the spare tire was in the way. In case anyone finds this thread in the future, you might have this problem if you have these two symptoms:

1. Quick metal on metal rattle. This is the sound of the bracket vibrating against the muffler heat shield. It matches the description of a loose parking brake cable
2. Clunking over bumps. This is the sound of the muffler bouncing up and down. It matches the description of failing rear shock mounts.

You are looking at a guy with well adjusted parking brakes and a nice new set of rogue engineering shock mounts.

You didn't mention it in your post - but I hope you put at least one screw through both, better if at least two... otherwise, there is too good of a chance the JB will break free... you can always do such after the fact, just use self-threading sheetmetal screws. Then as I mentioned: the JB is hydroscopic, ie, will readily bind with water, so any bare metal will start rusting, so, give the JB and especially edges thereof a blast of paint.

[The ZED]

I drilled two holes in the bottom of the trunk floor directly above where the mount is on the muffler and stuck a zip tie through. I used washers as support in the holes. That bracket weighs a lot more then a zip tie so I chalked it up to weight savings.

[Brad5161]

Mine just failed, this is the first info I found about how it mounts after doing lots of searching on the web. Part number 41128189985, INTERIOR REAR SILENCER BRACKET in case anyone else searches for this.

[TUD]

Reviving this thread... How many have experienced this issue & what did you do to resolve it?

[Randy Forbes]

I've had to repair several on Z3s; only the rearmost bracket.

Andy Maddux's (Leather Z owner) 1-owner 3.0 Coupe

[TUD]

Thanks Randy. It appears all four spotwelds have failed on mine, mileage unknown. The PO installed one sheet mental screw to band-aid the problem. Considering I am OCD this will now have to be repaired properly. Bodyshop? Suggestions??

[Chamberlin]

Just picked up a 2001 3.0 Coupe a few months ago. I heard a big rattle on my initial test drive, but figured it was just the tool kit in the rear bouncing around... well I finally got under there and found a piss-poor repair of the exhaust hanger bracket. They had drilled out the blown spot welds and installed aluminum rivets! Only two were left, and the they were both stretched and about to break also. So I opened up the holes just a tiny bit and installed 4 stainless steel bolts with locking nuts. I also cut a corner off the bracket to give clearance for the bolt, and also the Allen wrench access (lower left bolt in the photo). I don't think this bracket will give me any more problems.

[mikey1951]

Mine gave way today at 121k & I stuffed a shock rag between the heat shield & underbody until I can fix it this weekend. Nice pics and great info as guides to remedy this problem.