* Wear and Tear: Like any mechanical component, the vacuum pump's internal components (gears, vanes, seals) wear out over time and mileage. This is the most common cause of failure, especially in a vehicle of that age. Excessive vibration from the engine can also accelerate this wear.
* Seals Failure: The seals within the pump are crucial for maintaining vacuum. If these seals degrade or become damaged, they can lead to vacuum leaks and pump failure. This is often a result of age, heat, or contaminants in the oil.
* Bearing Failure: The bearings supporting the pump's internal components can wear out or seize up, leading to noise, reduced efficiency, and ultimately, failure.
* Low Oil Level: Insufficient engine oil can lead to insufficient lubrication for the vacuum pump, causing premature wear and failure.
* Contaminated Oil: Dirt, debris, or other contaminants in the engine oil can damage the pump's internal components and accelerate wear.
* Overheating: Excessive engine temperatures can damage the pump seals and bearings, leading to failure.
* Improper Installation (if replaced): If the vacuum pump has been previously replaced, incorrect installation can lead to early failure.
* Manufacturing Defects: While less common, some vacuum pumps might have manufacturing defects that lead to premature failure.
* Excessive Load: Demanding operation of vacuum-powered accessories (brakes, etc.) can put additional stress on the pump, potentially contributing to its failure.
To diagnose the specific cause, a mechanic would need to inspect the pump itself, checking for worn gears, damaged seals, and seized bearings. They would also check the engine oil level and condition. Often, the symptom of a failing vacuum pump is a lack of vacuum, impacting components like the brake booster (resulting in a spongy brake pedal), and potentially power steering if it's an integrated unit.
