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Re: hard brake pedal
Don't like intermittent brake faults
Servo or vacuum failure would normally leave pedal hard and no braking assist.
For an intermittent failure either Vacuum is not being trapped by the servo check valve or not being released by the pedal movement, which opens a vent valve on the pedal side of the servo diaphragm
Turn engine off and leave for a while. Then pump pedal. If hard immediately or in first couple of pumps, I'd suspect a faulty check valve. Most servos will store enough vacuum for four maybe five pumps.
If memory serves, you still have a few days of warrantee left. Could be a good time to report a problem and set a stake in the ground in case its a servo change needed.
Won't be a fluid or pad/caliper problem as they would leave you with no pedal
Above is assuming the renault haven't messed with normal servo design.
Currently in Dancingdad's garage:
Qashqai 1.6 spark driven, Kia Sedona 2.9 TDI, Scenic II 15DCi 2004 (SORN) not quite RIP.