I´ve only had limited success with penetrating fluids, although they may not hurt, either.
As long as the old mufflers (and H-box) are in reasonable nick I always end up doing it this way:
Loosen the clamps and brackets - quite obvious, eh?
Try to wiggle the mufflers up and down, as well as sideways. They don´t want to co-operate, but if you try just a little bit more - just as much as needed to widen the slotted H-box opening a little - they should. No need to be brutal, only determined.
Go on with the wiggling and you´ll feel when things start to happen. Maybe also some mallet blows on the bracket behind the muffler rearwards will help. More wiggling, and soon enough you should (hopefully) have the muffler separated without damages - now if it (and the H-box) was reasonably sound from the beginning.
At least that´s the way I´ve always done it. Once I lost a couple of mufflers but they truly weren´t worth saving, anyway. Totally rotted, where they connected to the H-box.
Sture
As long as the old mufflers (and H-box) are in reasonable nick I always end up doing it this way:
Loosen the clamps and brackets - quite obvious, eh?
Try to wiggle the mufflers up and down, as well as sideways. They don´t want to co-operate, but if you try just a little bit more - just as much as needed to widen the slotted H-box opening a little - they should. No need to be brutal, only determined.
Go on with the wiggling and you´ll feel when things start to happen. Maybe also some mallet blows on the bracket behind the muffler rearwards will help. More wiggling, and soon enough you should (hopefully) have the muffler separated without damages - now if it (and the H-box) was reasonably sound from the beginning.
At least that´s the way I´ve always done it. Once I lost a couple of mufflers but they truly weren´t worth saving, anyway. Totally rotted, where they connected to the H-box.
Sture
