04 Coyote swap brake issue

Randy Hayes

New Member
May 26, 2022
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Hello, I'm hoping someone with the Hydroboost has ran into this issue and can help.

I bought the car and it had the OEM proportional brake valve installed and a rear remote mounted adjustable proportional valve. Looking at MMS they had a plug to install when you remove the guts of the OEM valve. While I was doing this the brake system drained of all fluid and when I filled it back up there is no brake pedal (all the way to the floor) In the manual it stated to drain the MC at the bleed fitting on the side and at the calipers, I have done this 3 times with a power bleeder and a couple with me wife helping from inside the car. It bleeds perfectly but still no pedal it goes all the way to the floor. The manual also states to start the car and turn the wheel all the way to stop and run over the relife valve for up to 5 seconds retun the wheel to center position and turn the car off. This is supposed to recharge the Hydroboost but it doesn't do I need to replace the hydroboost portion of the system or shoudl I convert to manual brakes? Any input is appreciated and thank you in advance for yoru help, Randy Hayes

I started messing with the brake system because when I went to adjust the rear proportional valve I found that the rear brakes were not engaging.


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