I have to replace the "center muffler" section of the exhaust system because both pipes adjacent to the connection to the "catalytic converter" section are so badly corroded they have large holes in them. I cannot get the car to pass state inspection. I guess the system is original. I managed to get the rear two sections separated from the cat section (and now the car sounds like a speed boat ). Now I am faced with carefully separating the rear muffler section from the center muffler section.

I have loosened the clamps but the (slotted) overlapping pipes appear to have "welded" themselves together.

Has anyone faced a similar plight?

Any ideas on what I can do to separate the two sections, because liberal amounts of WD-40 penetrating oil has had no effect?

I don't want to damage the rear muffler section because it appears to be very expensive to replace. The center muffler was bad enough!

Any advice would be appreciated.

Some suggestions: try heating the outer pipe, enough to get it to expand but not enough to damage it, then maybe they will come apart with some hammer taps.
If that fails, try grinding through the outer pipe lengthwise at the overlap, just enough to get a slot cut in it but not cutting the inner pipe beneath. This should relieve it enough you can get it apart with some hammer taps and/or prise it apart with a screwdriver.

Thanks for your suggestions. I tried my propane torch and liberal amounts of WD-40 and cutting longer slots... and eventually separated all three sections.

The new middle muffler section is installed and all parts are connected with new gaskets, clamps, nuts and bolts etc. I would have enjoyed this DIY if it hadn't been for everything welded together by rust and age.

The car is so quiet now I can't tell if the engine's running unless I hit the gas! I rather miss the speed boat sound.

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Simon Shearer

1986 420SEL

2000 Porsche 911 Millenium Edition Carrera 4
2010 Lexus RX 350
2002 Kia Rio
2002 Hyundai Accent