How do I reconnect flex pipe to down pipe? - PeachParts Mercedes-Benz Forum

shertex · #1 10-10-2015, 01:19 PM

This is on my 91 300D. Between the pipe that comes from the turbo and the down pipe there is a flexible section that's about 10" long. On the turbo side, it looks like it fits inside the pipe and appears to be secure. But on the other end it has become detached from the pipe. The two ends are touching each other but they are off center so that exhaust gas escapes through a 1/4" opening.

How do I go about securing that? Or is it something I have to replace? If I were to guess, the part of the flex pipe that's in the down pipe has broken. Can the flex pipe be lengthened? Also, I'm having trouble finding it in the EPC.

I am open to both correct solutions and "ghetto" solutions.

Thanks.

sixto · #2 10-10-2015, 02:19 PM

Something like this might do it albeit reducing flexibility -

I'm dealing with the same thing in the SD except the pipe came clear apart. One option is to have a generic flex section welded in place.

Sixto
83 300SD

vstech · #3 10-10-2015, 02:28 PM

two options...

cut out the broken flex, and weld in a replacement flex section. hard to find it in the correct size though.

the other option is order a replacement flex section from our site, or the dealer...

shertex · #4 10-10-2015, 03:00 PM

Sounds like my best bet is to order a new flex pipe from MB.

Sixto, I am glad to see you are no longer MB-less.

shertex · #5 10-10-2015, 03:01 PM

So how does the flex pipe connect to the solid pipe? Some sort of sealant?

shertex · #6 10-10-2015, 03:06 PM

I wondered about using Tiger Patch as a stop gap measure...but maybe that's a bad idea.

Dan Stokes · #7 10-10-2015, 04:58 PM

I had a heck of a time getting mine back together on my 617 (I'm guessing it's similar) but I fiddled and it did eventually slide together. I did tap the one end a tad bigger by working it carefully with a hammer from the inside. Once it was on there the clamp secures it very well. I'll wager that a new one will fit better.

The flex section on the 617 is really short - maybe 3 or 4 inches. Given that yours is about 6" I'd think you could get a replacement generic flex section though I'll confess that I've never gone looking for one. The one in my exhaust pipe (goes thru the front fender) is about 6" but it has a short section of solid pipe at each end so the total length is probably 8" or so. There's a pic in my build thread if you want to dig for it (no clue how to do a search for that).

Dan

mach4 · #8 10-10-2015, 11:06 PM

I just welded in a replacement generic stainless flex joint. It was a piece of cake. The old one had completely separated and rusted.

Here it is before clean up and after.

93k miles on it so far with no issues.

shertex · #9 10-11-2015, 05:29 AM

Looks like my best solution is to go to my exhaust shop and get them to weld in a new flex pipe. I'm still curious as to how well a Tiger Patch would work. I mean, as long as it holds and doesn't leak, what do I care? I suppose the tricky part would be getting a good seal over the corrugated surface of the flex pipe.

Dan Stokes · #10 10-11-2015, 09:22 AM

I thought you were referring to the flex bit up at the turbo. Maybe the newer engines don't use that?

Dan

shertex · #11 10-11-2015, 09:39 AM

Quote:

Originally Posted by Dan Stokes

I thought you were referring to the flex bit up at the turbo. Maybe the newer engines don't use that?

Dan

I have that as well....but there's a longer flex section further downstream.

Diesel911 · #12 10-11-2015, 10:33 AM

Quote:

Originally Posted by sixto

Something like this might do it albeit reducing flexibility -

I'm dealing with the same thing in the SD except the pipe came clear apart. One option is to have a generic flex section welded in place.

Sixto
83 300SD

I have used this type of clamp before and in the face of a lot of vibration the clamps will eventually fail in part because the metal stretches stretches and is thin.
In order for the above pic to last the 2 sections of pipe would need a section of tube that slides in and fits the inside diameter so that the Pipe remains centered to each other and all the clamp has to do is keep the 2 pipes from sliding in and out and seal.

Dan Stokes · #13 10-11-2015, 04:20 PM

Quote:

Originally Posted by shertex

I have that as well....but there's a longer flex section further downstream.

That longer piece (as shown in the pic) should be a piece of cake to get replaced at the muffler shop. I bought a universal one for my system and welded it in myself but I was building my own system so it was expedient for me to fit it as I made it. Anyhow, it's a piece of cake to do it and as long as the undercar end comes out in the same place the actual length of the flex section is unimportant.

Dan

shertex · #14 10-12-2015, 12:58 PM

Through a combination of Tiger Patch and some high temp tape, it looks like I've sealed it off pretty well. Anyone's guess as to how long it will last...place your bets.

vstech · #15 10-12-2015, 01:28 PM

4 hours