Removal of the plumbing
Removing the exhaust system may be necessary for a number of reasons. If you are replacing it then obviously you end up removing the old, but often I find the necessity to remove it for gaining access when doing other jobs. This job can be considered a simple one, but often it is not! There are pitfalls and it’s not easy dealing with these heavy tubes under the car.
What do you need?
Blocks of wood
Lets get started!
Decide whether to remove the entire exhaust or parts of it. If the exhaust is old I will warn you that trying to separate the tubes will be extremely difficult sometimes. If it is a single tube exhaust like the smaller engines or diesel versions, then you might be able to twist the tube around to loosen it. If you have double tube exhaust systems I will discourage you to even try and simply remove the whole exhaust system from the beginning, talking from frustrating experience.
Jack up your car, it needs to be quite high in the front so you have enough room for the downpipes under the car. Then support the middle and the rear muffler with wooden blocks or even better if you have spare jacks, so you could lower the exhaust fashionably. Then take off the four rubber hangers on your rear muffler.
Depending on your exhaust system it is most likely secured in other ways. In older Mercedes like the W123 it is clamped on at the transmission. Remove these clamps now.
Then the exhaust is only secured at the manifold-downtube. This is your most difficult job until now. The bolts are quite difficult to get to and your spanner will have very little room, a spanner with racketing function comes in handy here.
On the M110 engine, each down tube is hold on by two bolts, and they always are rusty due to the heat. Use lots of wd-40 to soak the bolts.
When you have loosened all the bolts, the exhaust will not smash into the ground since you already have supported it. Then just lower the exhaust slowly and wiggle out the downtube from the engine bay. If you have some wooden plates under the car the exhaust should slide out nicely eithout you scrathing it on the ground. You should now have removed the entire exhaust. Congrats!
If you are persistent to separate the exhaust to eliminate the need to remove the entire thing, you could use a gas torch to heat up the tube at the attachment point so it will loosen up, no promises though.