Much to my surprise this morning on the way to work, I nearly rammed the car ahead when it stopped in a country lane and I couldn't.
So I stopped to have a lookie at the vacuum system. It's a Pug 405 GLDT, and I can only see one vacuum pipe which appears to go directly from the pump to the master cylinder. I removed the pipe at the master cylinder end, and there was a little bit of suck with the engine idling (not enough to suck my finger hard onto the pipe though). If I revved the engine then it would suck a bit harder.
Driving wise after that point, on the motorway the brakes appeared to be fine. The power asssist only stopped working when travelling slowly, and giving the car a bootful in neutral would return the power assist temporarily.
So, does this sound like the vacuum pump, or could a leaky seal somewhere in the master cylinder explain it?
The car is on 227k miles, so bits are bound to be rather worn.
Cheers!
Tony