You don't have to support the body at all to change bags, just block between axle and steel suspension members and jack the axle. At least that is the way I did it.
Gus, so is that done between the bags by crawling up in there or is this a different spot?
I'm sorry, I'm just not visualizing where you're putting the blocks.
I really don't want to crawl up under there to shove blocks in between the bags, but I also don't want to damage the chassis or engine mount or frame... Hmm
Mung, I like your idea in principle, but I don't see how I'd be able to rig something that would stand up to road travel and not deploy on its own, yet still be usable. I'll give it some thought.
For the purposes of what I was doing I put the blocks under what I believe to be the front of the engine mounting bracket. The book says to do that. But based on what you guys are saying and the way I understood the way these engines are mounted, that sounds like a pretty bad idea!
It was mostly "just in case" as the bags were ok holding air. I'd just like to know for the next time I'm under there and the bags are not so ok
It sounds like I do need to make some run-up blocks for these types of adventures, although run-up blocks would not have worked in this situation, since the system would not hold air and the brakes would not have disengaged.
For the front I just put blocks ahead of the radius arm bushings under the radius arm mounts (one on each side). They seem like sturdy spots, but I'm not sure how much weight that spot can actually take. Don't know if the chassis weight can be sitting on them.