Ds3 brake issue

[RobD70]

Hi can anyone please advise, brake pedal went hard without warning, I’ve replaced servo & master cylinder, recycled the abs pump before each time manually bleed a caliper, in the sequence the diagnostic tool told me to, but pedal still feels there’s no assistance, don’t know if I’ve missed a crucial step or there’s another step to do,

I would be grateful for any advice given

Rob

[xantia_v6]

Did you check that vacuum is getting to the servo? Maybe a check valve is blocked?

[RobD70]

Thanks for your reply, yes checked valve working ok

[PaulC5]

When the engine is turned off, if you use the brake pedal do you hear air going in to the servo showing it had vacuum in it ? If not check if the vacuum pump is working if it has one (could be broken or its connection to the cam shaft/whatever could be broken), if not just check if the hose to the servo is getting vacuum at the servo end with the engine running. Also check if the hose is in good condition and not collapsed internally.