Power assist on brakes randomly working

[bigbunch]

Hi I have a problem with my brakes on my 89 nissan I think its something to do with the check valve
I randomly lose the power assist on the brakes and clutch. Anypne experienced a similer thing?

Thanks

[the ferret]

If the probem comes and goes, then yes I would say the non return valve between the vacuum pump and the booster is faulty.
Petrol or diesel ?, ..... petrol has no vacuum pump, diesel is on the alternator.
Cheers, the ferret.