Question about Cars & Trucks
Hi. citroen c3 2006 petrol. Where the brake pedal pushes the brake plunger, there is now a constant hiss but the brakes work fine. Any ideas? Many thanks
Are you positive that there is nothing wrong with your transmission ?
Posted on Nov 27, 2013
SOURCE: when releasing the brake pedal
Sounds like you have a leaking brake booster. The booster is what supplies the power assist to the brake pedal and is located in between the firewall and the brake mater cylinder.
Eventually it will get bad enough to cause either the check engine light to come on for lean codes or cause the engine to start to idle poorly and possibly affect you ability to apply the brakes.
This is a relatively simple repair. You can remove the master cylinder from the booster. Leave the brake lines attached. Most of the time you can gently move the master cylinder out of the way and the lines will bend or flex with the movement. You only need to move the master cylinder just enough to squeeze the booster in and out. Then remove the vacuum line from the booster.
The booster is held to the firewall with four nuts that can be accessed under the drivers side of the dash. First remove the rod that attaches the booster to the brake pedal. Then remove the nuts that hold the booster to the firewall. Remove the old booster and install the new one.
I’m happy to assist further over the phone at https://www.6ya.com/expert/jeremy_d728a59f986299fa
Posted on Nov 26, 2010
SOURCE: 2005 Ford Escape Hissing sound
The power brake booster has a bad valve. I can't suggest where to find a new valve for it, but you can buy a rebuilt replacement. They are usually not hard to put on.
Posted on Jul 02, 2009
this noise is caused by a defective power brake vacuum booster, (big round thing behind the master cylinder) the diaphragm is leaking vacuum.
Posted on May 06, 2009
From your description this appears to be a Brake servo issue.
The brakes are assisted by a vacuum created from the draw off the inlet manifold, it gives assistance too the brake pedal pressure by a large tank/cylinder mounted on the Bulkhead/firewall.
I feel that the sound you a hearing is air being draw into the Brake Servo from the foot pedal seal and the reason for fluctuation in the engine is the vacuum from the inlet manifold is being upset.
Attention I suspect should be addressed to the Brake servo/pedal seal or gaitor.
I hope this clarifies your thoughts?
Please remember to rate my effort.
Posted on Jan 22, 2009
Tips for a great answer:
Oct 03, 2016 | 2006 Dodge Stratus
May 23, 2013 | Citroen Cars & Trucks
May 23, 2013 | 2006 Citroen C3 1.4i
Jan 15, 2013 | 1997 GMC Sierra
Sep 18, 2012 | Renault Megane Cars & Trucks
Sep 01, 2010 | 1996 Lincoln Town Car
Dec 27, 2009 | 2002 Audi A4
Dec 13, 2009 | 1998 Dodge Intrepid
Jun 23, 2009 | 2006 Chevrolet HHR
299 people viewed this question
Usually answered in minutes!