Stripped bolt

I presume you are working on a TRX400EX?

Are your bolts hex, phillips or allen head? I am going to guess they are hex head.

Generally if they are hex head, the cause of the problem is the socket being used to take them out - get a new socket and most of the time the problem is solved - then put it back together with new bolts.

In any case, the last resort (but efficient) is to use a 1/4" drill bit and drill the head off the bolt - then the filter cover can be removed exposing the shank of the bolt. If the bolt has not been over-tightened or otherwise locked into the threaded hole, the bolt will usually spin out with fingers - if the bolt it tight in the threads, at least there is enough shank sticking out to get pliers or vice grips on. If it is really screwed up (rusted or locktight'ed in the hole), it will require an experienced mechanic to extract and rethread the holes.

Yea it is on the Trx , & it is a hex head. im not sure if i stripped it im sure i did, i used 5/16 socket pretty sure shoulda used 8mm seeing how everything on it has been metric. but i will try it thank yoou.

Usually a 5/16 is a good substitute for 8mm as long as it is a 6 point socket and not a 12 point - if you were using a 12 point 5/16, you can probably still unscrew the bolt if you get a 6 point 8mm socket