DCMoney
Goblin Guru
I've been working through an issue with brakes for a few weeks. Brakes have been, vacuumed bleed, pressure bleed, and bleed the old fashion way.
With the car off the pedal is nice and stiff, with it running, edit: (when brakes are applied) the pedal slowly sinks to the floor. Faster after vacuum builds up.
Brakes are not spongy. I'm not loosing any fluid, there are no leaks. My bleeder screws are pointed up. Master cylinder was bench bled.
Things I've tried:
Bleeding till the cows come home.
Replaced master cylinder. Was bench bled.
Check valve on brake booster is working properly.
Pistons are holding the entire time and releasing as soon as you lift off the pedal, so its not a sticking piston.
Plugged both master cylinder ports, pedal does not sink.
Testing the front brakes and plugging only rear brake port, pedal sinks.
Testing the rear brakes and plugging only front brake port, pedal sinks.
Put short hoses feeding the master cylinder to watch the fluid level to make sure the fluid wasn't being displaced between the front and rear ports. After the initial press that dropped the level just a little it didn't move until you lifted off the pedal.
Is it possible to have too much vacuum assistance? When the car idles and you get on the brakes for the first time after a few seconds of it running you get that woosh sound of all the vacuum leaving the booster.
Could it be the booster? I figured it was ruled out with plugging both ports on the master cylinder and the pedal staying firm.
Other than replacing the brake calipers I'm out of ideas, any help would be appreciated.
With the car off the pedal is nice and stiff, with it running, edit: (when brakes are applied) the pedal slowly sinks to the floor. Faster after vacuum builds up.
Brakes are not spongy. I'm not loosing any fluid, there are no leaks. My bleeder screws are pointed up. Master cylinder was bench bled.
Things I've tried:
Bleeding till the cows come home.
Replaced master cylinder. Was bench bled.
Check valve on brake booster is working properly.
Pistons are holding the entire time and releasing as soon as you lift off the pedal, so its not a sticking piston.
Plugged both master cylinder ports, pedal does not sink.
Testing the front brakes and plugging only rear brake port, pedal sinks.
Testing the rear brakes and plugging only front brake port, pedal sinks.
Put short hoses feeding the master cylinder to watch the fluid level to make sure the fluid wasn't being displaced between the front and rear ports. After the initial press that dropped the level just a little it didn't move until you lifted off the pedal.
Is it possible to have too much vacuum assistance? When the car idles and you get on the brakes for the first time after a few seconds of it running you get that woosh sound of all the vacuum leaving the booster.
Could it be the booster? I figured it was ruled out with plugging both ports on the master cylinder and the pedal staying firm.
Other than replacing the brake calipers I'm out of ideas, any help would be appreciated.
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