Neverending Bosal Exhaust Problems

[dcollin]

OK so the first PITA was installing it. Things didn't line up. I couldn't get the rear rubber hanger on to the new system.

I bought, from BavAuto, the exhaust and the installation kit. I know-should've went with Steve. One of the doughnuts that goes to Cat wasn't there. Put it together anyway. It leaked.

Drove it for a sort while. It knocked, rubbed, bumped.

Took it to a local muffler shop to try to get it to stop, and put the doughnut in. Cost me 120.00. Picked it up Fri. No more leaks. But it is still knocks on the body when I go over a bump. No noise at all side to side.

The tail pipes are about a quarter inch away from the body. Anybody have this issue? I know now about the problems of Bosal. The guy at the muffler shop said he's heard they're junk when it come to fit.

[535is-pa]

there is a exhaust hanger in the back of the car. like where you would have a tow hook. there is a bracket that goes there and another rubber thinggy. (note this makes 3 rubber hangers total) this needs to be there!

if you cannot get this hanger on or don't have the bracket like my buddy. use a coat hanger tied into the holes for the hanger and tighten it up with a wrench. this has worked well for my buddy's e28 for about 3 years. its not professional but it does work. and the hack job isn't visible unless you get under the car and directly look for it.

[Rich Euro M5]

there is a exhaust hanger in the back of the car. like where you would have a tow hook. there is a bracket that goes there and another rubber thinggy. (note this makes 3 rubber hangers total) this needs to be there!

Plus each of the hanger brackets are adjustable. The two mounted on the rear subframe will let you slightly rotate the entire catback system so the tailpipes are horizontal to the ground. The rear mount lets you move the tail pipes in a vertical direction. When the system is properly hung it shouldn't bang on anything.

Rich

[dcollin]

I do have the rubber thing and bracket, but there is no adjustment.

I could take it apart, make a slot myself, but I think I would only gain another 1/4". I'm not sure that would solve the issue.


[img][img]http://i73.photobucket.com/albums/i238/ ... ket002.jpg[/img][/img]

[BRRV]

Plus each of the hanger brackets are adjustable. The two mounted on the rear subframe will let you slightly rotate the entire catback system so the tailpipes are horizontal to the ground. The rear mount lets you move the tail pipes in a vertical direction. When the system is properly hung it shouldn't bang on anything.

Absolutely right. Even with a Bosal, not known for it's fit. The hangar brackets in question are what you attach the resonator to on the body with rubber rings, in the general vicinity of the rear subframe. There are bolts (one on each side of the car, one for each bracket) which allow you to raise or lower the resonator in relation to the rest of the exhaust, getting it level. I think the bolts are 13MM and wil probably need some penetrant on them. These brackets are what you attached the upper portion of the rubber ring to.

The bracket at the rear of the car just hangs the muffler portion with the supporting ring, and should have clearance with the valance as spec'd in Bentley's. If not, adjusting the hangar brackets will give additional clearance, IIRC ( I did this job just last summer).

It's common knowledge that these exhaust systems need to be fitted - installed loosely and then checked for clearance and so on before tightening everything down. To do this you do have to have the center bolts on the cat/resonator connection installed and torqued down properly.

Lastly, although I think it's likely just a fit issue, your bracket at the back of the car could be bent. This is available (BRACKET 1 18211178463 $17.41) and might need to be replaced.

[Rich Euro M5]

I do have the rubber thing and bracket, but there is no adjustment.

I could take it apart, make a slot myself, but I think I would only gain another 1/4". I'm not sure that would solve the issue.


[img][img]http://i73.photobucket.com/albums/i238/ ... ket002.jpg[/img][/img]

I just looked under my '86 535i which has a Zender rear skirt and noticed I have an additional strap between the muffler mount and the actual muffler. This is probably part of the Zender kit to get the muffler a little lower hang. The ETK doesn't show this extra strap.

But as Rick mentioned, you have to have the exflanges at the catback loose, then move the two subframe mounts up which tilts the muffler tips downward, setting the clearance per the Bentley. Once you have this clearance set, you then snug up the flanges between the forward cat section and catback..

Rich

[dcollin]

OK, I tried adjusting the rear axle mounting brackets all the way down: same clearance.

Then I tried them all the way up: No clearance.

By the way my rear mounting bracket is fine. Now I'm definately at a loss. Any other adjustments like: Center mounting bracket?

Also what about fabricating a separate bracket for the rear, so it hangs down farther?

[Jeremy]

On the bracket that hangs on with the donut in the picture you show . . . is the nut going into a captive nut on the bracket or a loose nut? I seem to remember that hole being slotted for some reason, to allow for some vertical adjustment of the tailpipe.

Perhaps that was a different car altogether, but the same concept could work here. Easier than relocating the hangar on the car in any case. Grind off the captive nut, make the hole slotted for adjustment with a grinding wheel, or simply drill a new mounting hole. In either case attach with a nut and bolt instead of the captive nut.

Then, in 2-3 years when the Bosal rusts out and need to be replaced, buy a quality exhaust system. This is one reason why relocating the bracket for the poorly designed Bosal is a bad idea.

Jeremy

[dcollin]

OK , I just got back from a test drive. It still is hitting against the rear valance, although not quite as bad.

Yes, Jeremy, it is a captive nut on the bracket., and my original thought was to do just what you said. Unfortunately, I've only got about a 1/4" of metal on top of the bolt. I'm not sure that's enough.

I think I'll have to fab my own bracket at this point to bring it down about a 1/2". Believe me I've got plenty of other things I need to do, other than to f w/ this . Like I said it has been a PITA from the start.

Live and learn..I guess