Progress Thread 1986 GT 5.0 Mustang Restoration/Bringing my dad's old car back to life


clean it good before insertion
Jul 3, 2005
Dallas, TX
Kyle, take a deep breath and relax a minute.

When you are ready, check that all connections are tight, bleed the master (it can be done on the car), and then do the complete bleeding process again.

Check to confirm that the booster vacuum is hooked up correctly.

If your problem is still there then take a hard look at the booster, new or not.
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Active Member
Apr 23, 2021
Goleta, USA
Bad booster would just feel hard. Sinking to the floor usually means air in the system still, however if the pedal gets rock hard and stays at the top of the stroke with the engine off, it could mean there isn’t air.

All the lines are new? No signs of leaks anywhere in the system?
Yea, no leaks, it builds and holds fine after a couple pumps with the engine off, I replaced the rubber lines, not metal.