Usage:
There are several methods that can be used to make repairs to damaged threads in cast iron housings and cylinder blocks. One method is to use a Heli-Coil insert. Also, a 9S3500 or 9S3700 Thread Insert Repair Kit can be used.
In some applications, a steel rod with threads can be used to repair damaged threads. This procedure can be used when no more than one hole in a bolt pattern is to be repaired. This procedure can not be used to repair threads in holes for cylinder head bolts or studs, holes for main bearing bolts or studs, connecting rod holes or hydraulic system components. Also, this procedure should not be used to repair threads in the transmission for the long bolts that hold clutch packs together.
The instructions for this procedure are as follows:
1. Illustration 1 shows an example of a hole with damaged threads. A steel rod with threads will be needed that has a diameter of at least 1 1/2 times the largest diameter of the damaged area.
Illustration 1. Example of hole with damaged threads.
2. Drill and tap the damaged hole to the size needed for the steel rod. Clean the threads in the hole and on the steel rod with 6V1541 Quick Cure Primer. Put 9S3265 Retaining Compound on the threads of the steel rod and install the steel rod in the new hole. See Illustration 2.
Illustration 2. Install steel rod in new hole.
3. Cut the steel rod off just above the surface as shown in Illustration 3. Drill a 3.5 mm (.136 ") diameter hole between the steel rod and the casting. Use a 8-32 tap to put threads in the hole. Use 6V1541 Quick Cure Primer to clean the threads in the hole and the threads on a 1H3331 Screw. Put 9S3265 Retaining Compound on the screw and install it in the hole as shown.
4. Cut the top of the screw off so it is even with the top of the steel rod. Use a file to make the top of the steel rod and the top of the screw even with the surface of the casting.
5. Drill and tap the steel rod to the dimensions of the original hole as shown in Illustration 4.
Illustration 3. Install machine screw to hold steel rod in position.
Illustration 4. Damaged hole that has been repaired with a steel rod.