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Is the vacuum portion of vacuum-assisted hydraulic brake systems required to have a warning device?

Document
FMCSA-VEH-393.51-Q02.cm_.docx (22.44 KB)

393.51: Warning signals, air pressure and vacuum gauges.

Guidance Q&A

Question 2: Is the vacuum portion of vacuum-assisted hydraulic brake systems required to have a warning device?

Guidance: No. Only the hydraulic portion of vacuum-assisted hydraulic brake systems is required to have a warning device. FMVSS No. 105 does not require a warning device for the vacuum portion of the vacuum-assisted hydraulic brake systems. It is the intention of the FMCSA that § 393.51 be consistent with FMVSS No. 105.

Regulatory Topic: Does vacuum assist on hydraulic brakes need a warning device?
Effective Date: Sunday, May 4, 1997
Issued Date: Friday, April 4, 1997