why is the brake line whistling at fire wall?
on 1991 Jeep Wrangler

brake line whistling at fire wall on driver's side

Asked by for the 1991 Jeep Wrangler
The brake line should not whistle. If it is a metal line carrying fluid it may vibrate with some engine resonance if it is not properly secured. If it is a vacuum hose the check valve may have a problem, or you have a vacuum leak in which case the engine would run poorly.