Mechanics

I HAVE NO BRAKES AFTER INSTALLING NEW BRAKE BOOSTER

2005 Mercury Mariner • 120,000 miles

I have a 2005 Mercury Mariner V6 with 4 wheel disc brakes. The truck has 120k on it and I have been having some issues as of late. The truck has had the hissing sound coming from the brake pedal and I was also having engine issues that developed around the same time. When I would depress and hold down that brake pedal the car would almost stall out and as soon as I released the pedal the rpms would raise back. The issue progressed to the point that without pressing the brake the vehicle would start to sputter and then(I assume) the computer would try to correct for the vacuum leak and the rpms would raise and smooth out. I purchased a Cardone remanufactured Brake Booster but the push rod was almost 2/3" shorter that the one that I removed from the vehicle and when it was installed the push rod caused the brake pedal to not make contact and kept the brake lights on. After more research I found that several people had this problem with the remanufactured boosters. So I stepped up and purchased a brand new Power Brake Booster from Berge Ford. I had called around to several Ford parts departments and provided them with the VIN and they were the only dealer in the valley that had it in stock. After the 85 mile round trip I installed it in my vehicle but the push rod going through the firewall seems to be too short and it too is causing the brake lights to stay on. I decided to complete the installation and hope that after bleeding the brake system the pedal would come back and close the brake switch. After I bled the brake system and test drove the car, the brake lights are still on and the vehicle has almost no brakes. The pedal feels firm but it goes all the way to the floor and the car will barely stop even at only 10-15mph. I am not sure if the push rod being too short is the issue or if it something else. Any thoughts?
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Birdsdad
September 9, 2012.



Symptoms indicates the problem is due to a failed master cylinder rather then the push rod lenght.

You would need to get the brake switch problem addressed as well.

KHLow2008
Sep 9, 2012.
Thanks. Have you heard if there is an issue finding a matching master cylinder/brake booster combo? I was told that I had to buy them together but even through fordparts. Com you can only by them as seperate parts. Any idea on the brake switch other than what I have read(i.E gluing something on to fill the gap). Thank you again.

Tiny
Birdsdad
Sep 9, 2012.
The master cylinder should come separately.

As to the brake switch, the pedal should be further away than normal and if don't mind that, you can find some sort of attachment for the bracket to decrease the clearance to close the switch. Make sure whatever you do, it shold be solid and don't fall off.

KHLow2008
Sep 9, 2012.