What Causes the Fiesta Half Shaft Oil Seal to Leak?
2 Answers
Fiesta half shaft oil seal leakage may be caused by overfilling of the drive axle reducer oil, blockage of the drive axle reducer vent hole, or deterioration and aging of the oil seal. Overfilling of the drive axle reducer oil: If the drive axle reducer is overfilled with oil, causing the oil level to exceed the normal height, the excess oil should be drained to maintain the standard oil level. Blockage of the drive axle reducer vent hole: If the drive axle reducer vent hole is blocked, the oil temperature and pressure will rise during driving, forcing the oil out and damaging the oil seal, which can also lead to leakage. Deterioration and aging of the oil seal: It is also possible that the oil seal has deteriorated or aged, losing its sealing function. In this case, the oil seal should be replaced.
After driving my Fiesta for a few years, I noticed oil stains near the drive shaft, which appeared to be leaking from the axle seal. This is usually caused by seal aging or wear. I remember back then, small oil droplets would appear near the wheel hub after parking overnight. I asked my mechanic friend, and he said this is common with Ford models, especially after high mileage. While not a major issue, it needs timely attention. Leaking transmission or differential oil can contaminate the road and may lead to insufficient lubrication, causing premature damage to the axle bearings. I recommend checking yourself first: look for oil stains under the car after parking, or ask the technician to take a quick look during regular oil changes. If it's a minor leak, you can monitor it, but if the leak worsens, replace the seal—a cheap fix costing tens to a hundred bucks. Don't let it escalate into a major differential repair. Be cautious if the car feels unstable at high speeds.
