If you fit front disc brakes you will need to have the handbrake on the rear which is unusual on early drum brake Renault 4 I have converted my left hand drive Renault rodeo and fitted a servo while I was restoring the car this was from a Renault 5 mark 1 but it looked some adapting to get it to clear the inner wing as with dual circuit brakes you need the servo mounted to the pedal box welcome to message me for more information I might have some parts available