Renault clio mk3 brake bleeding- doh moment

[scoobydo123]

So working or car for Sons girlfriend. It failed MOT and they didnt have the money to get repaired at the garage. Needed new rear caliper and wishbone. Changed rear caliper just lost a couple of drips. Bled the rear caliper with owner keeping eye on cylinder only to find they let it drop down low I believe :-( Got everything bled again and pedal is rock solid with engine off. When engine is started it is quite soft at the top of the travel compared to engine off. Have took it to gravel track and engaged ABS is it just a case of bleeding again now. Gutted as if the helper was paying proper attention then would have been all sorted. Anyone got any advice for me please? Car is in Romford if anyone is local that has the required scan tool to activate abs so I can bleed the pump if that is the problem

Tks in advance