explanation
There are 2 pictures,
1) hole.jpg; and
2) break_point.jpg
Symptoms:
1) Noise for a few days before incident; and
2) Smoke; and
3) 4 out of 5 bolts are missing
Explanation:
Break point showed the location of the knuckle which holds the calliper and knuckle thru a calliper sliding pin is broken. This cause the calliper lose and randomly hits the alloy rim from the inside. So, there is no problem visible from outside by just looking at the rim and tire.
At the day of the incident, probably there was damage to the rim and after a bad angle bump, a hole was made and caught the calliper, and if the car moves forward a bit more, the rotational force will drag the rim out of its original position. Smoke came out due to the pressure escaped from the hole that was created at time of incident. Tire is still good. Up to now, symptoms 1 and 2 were explained.
Then why 4 out of 5 bolts are missing, bolts were loosen due to the constant knock to the rim by the losen calliper. When the incident happens, the drag from the moving vehicle with caught-up calliper and rim very likely to drag some bolts and fly off. We also tested in front of the owner what happened if only 1 bolt is fasten, the rim will not move side to side and touch the calliper because there is clearance between them.
Resolution:
1) Repair knuckle
2) Replace the same alloy rim
Status:
1) Knuckle ordered and ready to put on
2) We have a difficult time find the same rim because its a discontinued item from the manufacturer.
End of Report