Identifying characteristics

The brake booster boost is produced by vacuum pressure.

Distinguishing features: 

Fig 1: Identifying Brake Booster, Hydraulic Unit & Control Module

Courtesy of VOLKSWAGEN UNITED STATES, INC.

1- 10" brake booster

2- Hydraulic unit

3- Control module, 25-pin (bolted to hydraulic unit)

Distinguishing features of ABS, ABS/EDL and ABS/EDL/ASR ITT Mark 20 IE hydraulic unit 

Fig 2: Identifying Dimension A On Hydraulic Unit

Courtesy of VOLKSWAGEN UNITED STATES, INC.

• Dimension -A- 100 mm vehicles with ABS
• Dimension -A- 130 mm vehicles with ABS/EDL
• Dimension -A- 130 mm vehicles with ABS/EDL/ASR