Exhaust Jacks

Very good.

They do benefit from a ply or rubber sheet disc on top for protection from sharps and maybe on the bottom as well.

Earlier ones worked best with three pairs of hands but current models are OK with one.

Mine's in the shed, I've used it twice and it worked but a bottle jack and plate is easier and takes up less space so I don't take it with me anymore.

I had great success with mine back in the 70's.
It is important to arrange the top to be directly over the bottom to lift vertically.
If you want to move the vehicle out of a bog, arrange so the top is offset toward the direction you want to move, so when you pick the vehicle up, it falls over in the direction you want.
I managed to move a Mini Moke about 50 meters across a mud patch one day, and as we were cleaning up, a Land cruiser came along and needed the same cure.
I wouldn't go anywhere without it then.
Doesn't work well to change tyres, unless you use it to put the side of the vehicle onto a block or log or whatever to do the necessary, but was excellent to get under where the space is skinny.
The other move was to lift up the Moke if it was the back, and get the wife to shove something underneath to hold it.
Couldn't lift the front though.
Bob

Mine works as intended just fine...specifically what is the problem with yours..??

Yes, you do need to make sure it goes up straight. It might need a couple of shots.

The big plus is flexibility in locating it.

They must work in some cases Have look at some episodes of " Highway to Hell" where they use large airbags to lift loaded B Double trailers up with them.
Definitely larger than the ones generally available, but certainly do the job

Ross
as a low pressure vessel manufacture I have made heaps of them & if you want a good one & one that works well you need to look at the Volume of the bag & how much psi it can take so you can work out the weight it can lift, remember the bigger the bag the less PSI needed & they work far better if they are hi volume low pressure

look at what & how they are made EG: pvc with be cheaper & lighter but will not last as long as one made of Hypalon material & check the gauge of the base cloth (EG, the higher the denier/desitex the stronger the fabric should be) & check the fittings & how they are fitted & work

my own bag has no problem lifting my Isuzu 4x4 motor home or a truck up to 8 ton of the ground with less than 1 psi

If you have a turbo then its not a good idea.
The extra exhaust back pressure they cause can blow turbo seals...

Russel Coight had fun with one on All Aussie Adventures