GENE RAL INFORMATION 17 1 '- __ Filed Slotted insert . Follow the manufacturer's instructions when in- stalling their insert. I fi t is necessary to drill and tap a hole, refer to Table 4 for metric tap and drill sizes. Removing Broken or Damaged St uds If a stud is broken or the threads severely damaged, per- form the following. A tube ofLoctite 271 (red), two nuts, two wrenches and a new stud will be required during this procedure. If a large portion of the remainder projects out, try grip- ping it with locking pliers. If the projecting portion is too small, file it to fit a wrench or cut a slot in it to fit a screw- driver. See Fi gur e 44.
If the head breaks off flush, use a screw extractor. To do this, centerpunch the remaining portion of the screw or bolt. Drill a small hole in the screw and lap the extractor into the hole. Back the screw out with a wrench on the ex- tractor. See Figure 45. I . Thread IwOnuts onto the damaged stud. Then tighten the two nuts against each other so that they are locked . NOTE Ifthe threads on the damaged stud do flatal- low installation of the two nuts, remove the stud with a stud remover or a pair of locking pliers. Remedying Stripped Thre ads 2. Tum the bottom nut counterclockwise and unscrew the stud. Occasionally, threads arc stripped through carelessness or impact damage.
Often the threads can be repaired by running a tap (for internal threads on nuts) or die (for ex- ternal threads on bolts) through the threads. Sec Figur e 46. To clean or repair spark plug threads, a spark plug tap can be used. 3. Clean the threads with solvent or electrical contact cleaner and allow them 10dry thoroughly. 4. Install two nuts on the top half of the new stud as in Step 1. Make sure they arc locked securely. 5. Coat the bottom half of a new stud with Loctite 271 (red). NOTE Tap and dies can be purchased individually or in a set as shown in Figu re 47. 6. Tum the top nut clockwise and thread the new stud se- curely. 7. Remove the nuts and repeat for each stud as required.
If an internal thread is damaged, it may be necessary to install a Helicoil (Figure 48) or some other type of thread 8. Follow Loctitc's directions on cure time before assem- bling the component.