Peugeot 806 brake problems

[Bxtzdkyle]

The brake pedal is hard even with engine running. It has done this occasionally in the past but getting worse. There is a vacuum from the pump. She also had mentioned the engine revs sometimes drop like a big load has been applyed. Looking online seems to suggest the booster(servo) is likely to be the problem. Anyone offer help or advice if it is the booster how to replace? Thanks

[Oldpug]

I take it the engine is diesel.
From experience the vacuum pump will be the most likely cause. You say there is vacuum but is there enough? They don`t cost the earth and are very easy to replace.
Brake servos very rarely pack up,when they do you may hear a "hissing" sound down by the pedal

[GiveMeABreak]

The brake pedal is hard even with engine running. It has done this occasionally in the past but getting worse. There is a vacuum from the pump. She also had mentioned the engine revs sometimes drop like a big load has been applyed. Looking online seems to suggest the booster(servo) is likely to be the problem. Anyone offer help or advice if it is the booster how to replace? Thanks

Pop up your VIN here and this will provide us with all the details we need.

[Bxtzdkyle]

I will try that I have a spare for it I had a leaking servo on a 306 that hissed when pedal pressed like you mention but not noticed it on this. Will change it tonight and see how it goes