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Are vacuum gauges required on the vacuum portion of vacuum-assisted hydraulic brakes?

Document
FMCSA-VEH-393.51-Q03.docx (12.35 KB)

Section § 393.51: Warning signals, air pressure and vacuum gauges.

Guidance Q&A

Question 3: Are vacuum gauges required on the vacuum portion of vacuum-assisted hydraulic brakes?

Guidance: No. Section 393.51(d)(2) requires only that CMVs with vacuum brakes (not hydraulic brakes applied or assisted by vacuum) be equipped with a vacuum gauge.

Regulatory Topic: Do vacuum-assisted hydraulic brake need a gauge on the vacuum portion?
Effective Date: Sunday, May 4, 1997
Issued Date: Friday, April 4, 1997