Give it a couple of days soak in penetrating oil...
...then a 27mm socket and big ratchet.
If they dont move at first..soak again...then try 'gingerly' with a
extension bar on the ratchet.
As Billy said... taking the load off them will help.
BTW.. I have never heard of T/bar bolts shearing...
....so Fingers crossed for ya!
Jo