Title: Check the air system build-up time.
Course: Diesel Equipment Technology II (20107-II) > Section: Brakes: Servicing Air Brakes

Checking the air system build-up time should include consideration of the following specifications:

- In the single air systems (built before 1975), pressure typically builds from 50-90 psi within 3 minutes with the engine at an idle speed of 600-900 RPM.
- When the engine is at operating RPM (check the manufacturer specifications to determine the correct operating RPM), the pressure should build from 85-100 psi within 45 seconds in dual air systems.

ASE 2: III. Brakes: B. Air Brakes: Air Supply and Service Systems (P-1)

Process/Skill Questions:

- How much pressure should a system have in vehicles built before 1975?
- How many minutes does a system require to build pressure in a single air system?
- What are the requirements for building a dual air system?