Hissing and whistling FJ40

owenwalk · 03-07-2007, 10:28 AM

Just bought a 72 40 and there are two concerns I'm hoping someone can direct me to a fix. The first is a hissing noise when stopped (engine on) and brake pedal down medium. When hissing, vacuum drops and engine runs rough. When I push hard on the brake, hissing stops, vacuum goes back up and engine runs smooth. Second is a whistling sound when vehicle is moving. It is coming from the engine/trannie and maintains a constant tone regardless of speed or gear. It stops when the vehicle is almost stopped (1-2 miles per hour).
Any ideas??

JGM · 03-25-2007, 07:48 PM

I had a similar experience for your hissing on my 71 '40. The rubber boot had come disconnected from the flange around the rob going through the firewall to the booster. I put that back in place, and no issues since. My engine didn't react to it, though.

Post this on mud and you will get more answers.

03-07-2007, 10:28 AM	#1 (permalink)
owenwalk Registered User Join Date: Apr 2004 Location: San Francisco, CA Posts: 27	Hissing and whistling FJ40 Just bought a 72 40 and there are two concerns I'm hoping someone can direct me to a fix. The first is a hissing noise when stopped (engine on) and brake pedal down medium. When hissing, vacuum drops and engine runs rough. When I push hard on the brake, hissing stops, vacuum goes back up and engine runs smooth. Second is a whistling sound when vehicle is moving. It is coming from the engine/trannie and maintains a constant tone regardless of speed or gear. It stops when the vehicle is almost stopped (1-2 miles per hour). Any ideas??

03-25-2007, 07:48 PM	#2 (permalink)
JGM Registered User Join Date: Nov 2004 Posts: 342	I had a similar experience for your hissing on my 71 '40. The rubber boot had come disconnected from the flange around the rob going through the firewall to the booster. I put that back in place, and no issues since. My engine didn't react to it, though. Post this on mud and you will get more answers. __________________ 1996 4Runner & 1971 FJ40

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