Broken flex pipe... - PeachParts Mercedes-Benz Forum

Actros617 · #1 03-06-2009, 10:49 AM

So my 300SD flex pipe (the small pipe that goes in between the turbo and the down pipe) split at the very end (near the fire wall) so every time I accelerate it makes a horrid buzzing noise and it's starting to get annoying, I Saw a flex pipe kit at autozone and wanting to know if that kit made for replacing that flex pipe that I currently have...

jt20 · #2 03-06-2009, 12:00 PM

exhaust is just simple plumbing. As long as you stay with your diameter, you can weld anything you like on.

For something like a flex section, you can always go softer than the original design as long as you retain the same strength, but you can not go stiffer.

The flex section aids in damping all the engine vibrations that would rattle your exhaust apart (bolts, mounts etc..) while allowing some length adjustments in every direction.

johninva · #3 03-06-2009, 01:59 PM

You can get something like

this

and weld it in place of your accordion bellows looking flex section. threads on here report using 3" but i found that to be way too big. I butt joint welded with 2 3/4. Major pain in the butt, getting the orientation & length correct, lots of putting it in and taking it out. Mine is a cali car which i think makes it harder to fit and un-fit the down pipe. Im all for saving $$ but it may have been worth it to spend the $130.00 and avoid the hassle.

pawoSD · #4 03-06-2009, 02:02 PM

Mine broke a while back and I just replaced the whole pipe...way easier.

Unless you have a welder....

Our Rav4 had that piece break up front....Toyota uses this odd "flexible metal" type contraption that eventually just separates from itself and falls off (it did last 12 years though....).....the shop welded in a new braided steel one like in that link....and it works great. The updated MB exhaust have the braided one too....

The guy at the exhaust shop made the comment that "morons designed this" in regards to the odd flex coupling on the Toyota.

Paulc66t · #5 03-06-2009, 05:32 PM

Mine started leaking a few months back. I bought the new pipe but haven't put it in yet. In the mean time I slipped a pieces of sheet metal w RTV sealer and hose clamps over it. It has been quiet for now. I need to fix it before next inspection.

Actros617 · #6 03-06-2009, 07:13 PM

so its 2 inches not 2 1/2... exhaust system are the easy but i am just dont have the space to work on.

pawoSD · #7 03-06-2009, 08:52 PM

Its metric and its closer to 2.5"....its ever so slightly smaller than 2.5"....to the point that a 2.5" pipe just barely slips over the stock stuff. Which is perfect.

Actros617 · #8 03-06-2009, 09:33 PM

Is there any high force required in removing the exhaust pipe form the turbo or is there a space between the exhaust pipe and the and the turbo and the flex pipe just join's them???

jt20 · #9 03-06-2009, 09:43 PM

there is a flange with 3 bolts running parallel to the turbo shaft that pulls the downpipe against a compression joint.

loosen them and send some light blows around the circumference of the down pipe only. It should pop right off.

pawoSD · #10 03-06-2009, 09:45 PM

The pipe has a flared flange at the end by the turbo, it has a bracket/clamp thing on it that holds the pipe to the turbo with 3 copper nuts on the three studs coming off the turbo. Not a big deal to get off, but those nuts can be annoying. And if the pipe is stuck it might need a couple gentle whacks from a hammer to jar it loose.