If you mean the front bumper follow this simple guide (I pranged my 172 mk2 and decided to fix it all myself, as a result I can remove a front bumper in under 10 minutes) You do not have to have the car on ramps, but make sure you have placed a dustcloth under the front end of the car.
First as a caution buy two of the rubber bungs used to keep the crap guards in place in the wheel arch (they are about 30p each), if you are careful you wont need them but its good to have them just in case.
Step 1 Remove rubber bungs holding the lower front crap guard inplace in the front wheel archs (they do come out with some pursuading). Pull guards away to expose the bumper mounting points.
Step 2 Undo front bumper mounting bolts (1 each side) if I remember correctly a small ratchet handle with a M10 socket is the best for this. Undo screws holding crap guard in place in wheel arch.
Step 3 Remove the self tapping screws holding the front valance(?) on to the front bumper (there should be 3 or so screws either side) These are the screws that hold the front splitter on on the cup I think (not sure Ive got a lowly 172 mk2).
Step 4 Remove the 2 bolts holding the plastic bit still attatched to the front of the bumper to the sump guard (about 18 inchs underneath the car spaced about 30 inches apart.)
Step 5 Unplug front fog lamp connector (if youve got a mk2 with the light washers, dont bother to disconnect the washer line unless you need to take the bumper away from the car.)
Step 6 (Nasty worrying bit) Use a flat head screwdriver (make sure you cover the end in something so as to not damage the paintwork). Insert screwdriver tip into gap between wing and bumper starting at end nearest the wheel, gently pry apart bumper from wing (gently pull bumper side down and away from wing) the bumper has three holes molded into it which clip into a molding on the wing. It is obvious when the bumper is unclipped as it loses rigidity.
Step 7 Under bonnet there are two plastic push clips holding plastic bit attatched to grill in place. To remove clips pull center bit (with groove) up, lift plastic bit up such that it can pass over the two bolt heads (or nuts) that protrude through it on either side.
Step 8 Once all above steps have been completed (with the help of a friend) gently slide bumper forward and away from car.
