W123 Muffler Replacement Question - PeachParts Mercedes-Benz Forum

RML · #1 10-27-2008, 10:37 PM

I purchased a new muffler from Fastlane for my 84 300D. I see that the existing exhaust system is welded together in one continuous piece, but the new muffler has a flare at the front of the pipe. Is the idea that I can cut the existing pipe and fit this flared end over the existing pipe and clamp it? Or should it be cut and welded in like it is now? Was it designed to be able to do it either way?

Thanks for any input.

#2 10-27-2008, 10:39 PM

Clamp. Trying to weld rusted old pipe will probably just make more holes.

tangofox007 · #3 10-27-2008, 11:06 PM

Quote:

Originally Posted by RML

Is the idea that I can cut the existing pipe and fit this flared end over the existing pipe and clamp it?

That's it. Just be sure to measure carefully before you cut.

Skippy · #4 10-28-2008, 03:47 AM

It's made to be clamped. If you like quiet, go ahead and do that. However, if I was in your situation, I would straight-pipe that shi'ite. Just a personal preference.

charmalu · #5 10-28-2008, 12:52 PM

Sounds to me some one cobbled together your exhaust. there are only
three pieces. the down pipe, the center muffler section and the rear muffler section.

the flange bolts together with 2 bolts at the end of the down pipe, and the rear and center section is a slip joint that is clamped together.

two bolts, 4 rubber donuts and the whole thing drops out.

did someone cut it off at the flange and weld it?

Charlie

tangofox007 · #6 10-28-2008, 01:14 PM

Quote:

Originally Posted by charmalu

there are only
three pieces. the down pipe, the center muffler section and the rear muffler section.

That's not how it rolled off the assembly line. In the original configuration, everything was welded from the lower downpipe flange aft.

RML · #7 10-28-2008, 03:27 PM

Ok. I get the picture. I am going to saw and then fit these pipes together. Should any muffler cement go in the joint or will the clamp do the job?

tangofox007 · #8 10-28-2008, 07:21 PM

Quote:

Originally Posted by RML

Should any muffler cement go in the joint ...?

No.

RML · #9 10-28-2008, 08:20 PM

Thanks guys. I'm off to the garage.

tobybul · #10 10-28-2008, 08:30 PM

May not need to point this out but give allowance for the overlap, I'd say at least 3". Also, I would use a metal cutting disc and make 2 slits opposite side on the old pipe which will help compress the end as you shove the new tail pile in it.

RML · #11 10-28-2008, 08:33 PM

Quote:

Originally Posted by tobybul

May not need to point this out but give allowance for the overlap, I'd say at least 3". Also, I would use a metal cutting disc and make 2 slits opposite side on the old pipe which will help compress the end as you shove the new tail pile in it.

Good point about the slits. I hadn't thought of that.

Simpler=Better · #12 10-28-2008, 09:18 PM

Paint the muffler cherry red, sell it on ebay as a high flow muffler for a civic(it's twice the size after all

)
And then straight pipe the diesel

RML · #13 10-29-2008, 09:32 PM

I unbolted the exhaust at the downpipe flange and lowered the whole thing to the floor. It is a Mercedes muffler and is one continuous piece from the tailpipe to the flange. There is no connector, joint or weld between the rear muffler and center muffler. The only welds are where the pipes join the mufflers. I seriously doubt that this is the original muffler so assume that a PO had it replaced at the dealer.

I found that the OD at the flare on the new muffler, which is an ANSA brand, is 2 3/8" and the OD of the pipe coming from the center muffler is the same. So the center muffler pipe is not going to slip into the flare. I suspect that if I bought an ANSA center muffler, the pipe would be the right size to slip into the flare.

I stopped at NAPA on my way home from work and they sell a solid sleeve with which you use two clamps, and a wrap around stainless sleeve that you bolt together. I brought home the solid sleeve, which is 2.5", (I didn't know the exact measurement when I was there but the muffler they had in their book was a 2.5" pipe). It is too big, so I will have to go back tomorrow and get the stainless wrap around which you tighten down. Looks like I'll have to cut some more pipe off the center muffler if I am not going to slip one pipe into the other to the tune of 3".

I toyed with the idea of painting the new muffler cherry red or some other interesting color, but I don't want to pimp out the car, so I bought a can of gloss black. I hope to finish this project this weekend. Thanks for all of the help.

tangofox007 · #14 10-29-2008, 10:25 PM

Quote:

Originally Posted by RML

The only welds are where the pipes join the mufflers. I seriously doubt that this is the original muffler so assume that a PO had it replaced at the dealer.

A MB replacement muffler is essentially the same configuration as the Ansa.

Quote:

Originally Posted by RML

I found that the OD at the flare on the new muffler, which is an ANSA brand, is 2 3/8" and the OD of the pipe coming from the center muffler is the same. So the center muffler pipe is not going to slip into the flare.

I measured my original exhaust pipe ('82 300D) and the OD is approx. 2 3/8." The OD of the MB replacement muffler slip joint is 2 1/2." I replaced the muffler about 15 years ago and recall that it went together without complication. I also recall that the parts vendor strongly recommended an OE replacement muffler vice an aftermarket one.

You might use an exhaust pipe expansion tool to open the muffler slip joint up a bit.

RML · #15 10-29-2008, 10:51 PM

Hmmm. Maybe it was the original muffler.

I don't have an exhaust pipe expansion tool but could probably take the muffler to a shop to have it done. There are two slits in the flare on opposite sides of the pipe. I am guessing this is what they are for, to expand the pipe. I might cut them a little deeper and that may give me enough room to get the center pipe in.