Jump to content



Recommended Posts

Just replaced the brake booster again. Did it 4yrs ago cuz the pedal was going to the floor and it was making a hissing sound. The first came with the master cylinder and I bled them. Things were good. Started doing the same thing. Pedal going to the floor with the hissing sound when it was released. New one didn’t come with a master cylinder so brake line weren’t disconnected. Pedal still goes to the floor. Pedal feels strong when car if off. After starting it goes to the floor. Could it be the master cylinder or check valve? Where is the check valve? It is the part that goes into the booster? That hose runs from the intake to the booster and then from the booster to the air tube after where the MAF sensor goes? Very frustrating. Do the brakes have to be bled after swapping the booster even though I did t disconnect any brake lines? When the car it running I can disconnect the vacuum line I take tube and I can feel it suck but I have no pedal. At my whits end please help

Edited by 1004ron
Link to comment
Share on other sites

@1Mtmind, Lets go back to the beginning.


1.Pedal went the floor. Replaced Booster and Master. Thing are OK.

2 Failure again with pedal going to the floor. Replaced Booster . Still the same.


So master is bad or air in the lines or no fluid. The hissing sound is because

the pedal is too far bleeding the vacuum inside


As a side note from Ford a long time ago when one could see the fluid in the master cyl.

was to have assistant pump the brake up 10 times and hold down. 2nd. person opens top

of the master to observe the fluid level. Release the brake pedal. If there is air trapped the

fluid will gush like a geyser from the master, indicating witch 1/2 of the system has air trapped. 

Link to comment
Share on other sites

So maybe the last booster and master went bad. I changed the booster again because it was doing the same thing as before. When all along it could have been the master and that got changed. Hmmm I’ll bleed the brakes tomorrow and see if that changes anything. I’d hate for it to be a defective booster. Meaning it’ll have to be reordered, taken back out and reinstalled. Everything went back together fine. Had a little trouble getting all four studs lined up into the firewall. Brake light switched work as it should also. Fluid is full with no leaks. Front rotors and pads do need to replaced. Pads are very thin. That’s next on the list followed by both front cv axles. Ugh. Just had to pop in one new coil a month ago. Swapped all the plugs too while it was opened up and accessible. Just put new rotors and pads out back two months ago. 

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Create New...