Any type of socket can be used to remove a 91' Cavalier wheel cylinder bolt that looks like a reversed torx. However, make sure the socket is a bolt head socket.
unbolt it
If we are talking about valve lifters, remove cylinder head and pushrods and lifters will be excessable.
Remove the radiator and take it to a radiator shop.
GO TO YOUR LOCAL LIBRARY AND COPY MANUEL
To remove the ignition lock cylinder from a 2004 Chevrolet Cavalier, first, disconnect the battery to ensure safety. Then, remove the steering column cover by unscrewing the screws securing it. Insert the ignition key and turn it to the "Run" position; look for a small pinhole on the ignition switch housing, insert a small tool to press the lock cylinder release pin, and pull out the cylinder. Finally, disconnect any wiring connected to the ignition switch if necessary.
Remove the water supply hose from your 1988 Chevy Cavalier thermostat housing. Remove the thermostat housing bolts. Lift the old thermostat out and drop in the new thermostat.
Remove the wiring harness from your 1988 Chevy Cavalier fuel pump. Remove the fuel lines from the fuel pump. Remove the fuel pump retaining bolts. Reverse the process to install the new fuel pump.
I believe that is a 3/8 Allen key.
May only be able to fit in an open end wrench.
My 2003 Cavalier uses a 3/8 hex key. It probably should be the same.
i would like to remove the backseat from my 1992 chevy cavalier
This is not for beginners. You have to drain the transmission, remove the axles, remove the transmission, install the new cylinder, then replace the transmission, axles, add new synchromesh fluid to the tranny, and bleed the clutch hydraulics. You can get the whole procedure from Autozone's website.