sorry got mixed up,remember that the rear lower arm bolts cant be removed meaning the subframe has to be dropped to change an arm,what a great design,remember doing a clutch and did flip them over when the subframe was out but didn`t have the problem you are having,sounds like the captive nut is seized and is turning on the bolt,sometimes there is no easy way but to try and judge the best you can where the nut is situated,you may have to lift carpets and try a hole saw to hopefully get above the nut and get a socket/spanner onto the nut,good luck
cdc
January 2011