Circlips serve a very important function in the industrial and automotive field. Circlips look like small wire rings. They have a section of the ring removed to allow the wire ring to flex inward under tensile strength, then expand into a groove. Circlips are commonly used to hold piston pins inside the piston top sleeve, where a screw, nut, or bolt retaining method would prove ineffective. Simple devices, made of high tensile steel, circlips can be installed in a matter of minutes, provided great care is used, along with the proper tool for the specific type circlip.
Inspect the circlip groove that will receive the new circlip. The inside of the groove must be spotless, with no grime or carbon build up. Use some carburettor cleaner and a tooth brush to thoroughly clean the groove. For heavy carbon build-up, use a small flathead screwdriver to clean the groove, running the screwdriver around the inside perimeter. Wipe it clean with a rag.
Determine the exact shape and size of the proper replacement circlip. Use the old circlip as a guide, or refer to your owner's service manual for the correct replacement. Make sure the pin, which must be retained, has been seated in the shaft or sleeve, far enough back from the groove to allow the circlip to slip inside. Use a medium size flathead screwdriver for a single hook type circlip. place the non-hooked end of the circlip in the groove, then use the flathead screwdriver to catch the hook.
With one hand, pull the hook toward the centre of the pin or shaft with the screwdriver. Press downward on the circlip with the fingers of the other hand. The circlip should snap completely inside the groove, and be recessed evenly on all sides. Wiggle it to make sure it is properly seated.
Use a pair of needle nose pliers if your circlip has the double hook wire ends. Place the bottom, rounded edge of the circlip in the groove as far as it will go. Grasp the double wire hooks with the tips of the needle nose pliers. Squeeze the pliers with one hand until the wire circlip compresses, then push it down inside the groove with your fingers and let go off the pliers handle. Look for the circlip to snap into the groove and seat solidly.
Use a pair of circlip pliers if you have a circlip that has a double flange on each end, with small holes centred in the flanges. Circlip pliers function just like needle nose pliers, except that the tips of the circlip pliers have very small pointed nipples which fit into each hole on the circlip. Place the circular end of the circlip in the groove. Place the circlip pliers tips inside the two small holes and squeeze the pliers. Push the circlip downward and release the pliers. The clip should snap into the groove.
Do not compress the pliers so that the circlip ends meet -- it is not necessary to apply that much pressure. Use only enough pressure to let the circlip clear the outer sleeve and slide into the retaining groove. Too much pressure on the circlip can also break it. Always replace circlips with new ones. Old circlips have suffered heat and friction, which make them brittle and remove their spring, or tensile strength.