Tap the working mufflers with a hammer over the entire surface, including the end faces. Don't be too timid when doing this.
If you hear a ringing sound with each blow, this means that the muffler tin is still in good condition.
It is very important to follow the sequence of assembly of the components in the spring-loaded bracket shown in the upper figures. The correct placement of the individual components is shown here.
The front suspension of the main muffler has a retaining rubber loop supplemented at the bottom with a rubber shock absorber as a stop.
The maintenance item "Checking the suspension and condition of the exhaust system" includes checking the rubber cushions (arrows) shown in these figures. They should not be damaged, i.e. have breaks or other damage, otherwise they should be replaced. In addition, note that the safety clips of the steel bracket at the retaining rings are bent by 90 degrees so that the fastening ring does not protrude by mistake. Do not clamp the fastening ring. In the figures on the right, this safety clip is clearly visible at the bottom of the fastening ring.
If the sound becomes duller in some places, it means that the outer shell is already weakened and holes will soon appear; especially if it is the cold season, during which salt is used.
When purchasing spare parts, please remember that sealing gaskets and self-locking nuts must be replaced with new ones.
[The original article is available on the website audimanual]