DynaBro
Well-Known Member
Wasn't the booster, wasn't the pads, isn't a vacuum (I don't think). So what is this problem? Ecoboost FX4. Truck will lose breaking at like 1mph, for example when in line behind someone at gas pumps, pedal will become very stiff, there is a groaning sound from what we think is the lower middle of the engine compartment or maybe even down at axle. I can recreate this issue at will and we had a hand on the ABS unit and it was not coming from there. I replaced the pads and booster, no luck. The groaning happens, the pedal is hard, truck slides forward a bit, I crush the pedal to get it to stop, and then everything is fine again. No issues braking at speed. Any ideas???