Lesson 1: The assumptions of repairability

In this lesson, we’ll explore the factors that influence whether it’s worthwhile to repair or refurbish a component. We’ll also discuss the conditions under which repair or refurbishment is a viable option.


  • Repair and refurbishment are essential maintenance activities aimed at extending the lifespan of components and equipment.
  • In some cases, the scope, technology, and cost of the intervention blur the lines between repair and renovation.

When to Repair or Refurbish

  • The decision to repair or refurbish a component depends on several factors:
    • Availability: If the part is not readily available in stock, it may be more practical to repair or refurbish it.
    • Economics: Sometimes, even if a spare part is available, refurbishing the existing component can be more cost-effective.
    • Quality Improvement: Repair or refurbishment might result in a component of higher quality compared to a new replacement.

Commonly Repaired Components

  • Several types of components are frequently candidates for repair or refurbishment due to specific defects:
  1. Serrated, Ribbed Shafts: These components often experience defects in various locations, including: I. bearing wear, II. rib wear, III. chipping, IV. surface quality deterioration under sealing rings, V. thread damage, and VI. galling.

  1. Cast Iron and Aluminum Castings: Components like equipment housings and their internal bores can suffer from issues such as cracking, wear of cylindrical casings in internal bores, thread rupture, and chemical or thermal corrosion.


  • Repairability and refurbishment are crucial aspects of maintenance.
  • The decision to repair or refurbish depends on factors like component availability, economics, and the potential for quality improvement.
  • Certain components with specific defects are commonly considered for repair or refurbishment.

This lesson highlights the considerations that maintenance professionals should keep in mind when deciding whether to repair or refurbish components. Understanding when and why to choose repair or refurbishment can lead to more sustainable maintenance practices and cost-effective solutions.

Read the textbook from page 1-5. You can find the textbooks’s content on this link.

Go back Quiz