Hi. Difficult one this. On my xtype diesel when switching off the engine I have always had quite a healthy residual amount of vac for the brakes. So much so I could back the car down my sloping drive with the engine off for a while before the brakes gave out. Car was in for full service yesterday and when I got home I discovered that as soon as the engine stops I have instantly no brakes, nothing, and the pedal becomes solid. With the engine running the brakes are as normal.
Any suggestions please.

 

DUNKS, I would be looking at the line between the intake and the brake booster. If that line develops a crack between the booster and the bulge in the line (which is a check valve), it will cause what you are seeing as the built up vacuum can then escape. If it isn't that, then you may have a small hole in your brake booster diaphragm which would then require you to replace the brake booster.

 

Thanks I will check.

 

Diesel has no vacuum on inlet manifold, instead it has a vac pump on the end of one of the camshafts.
Check the vac pipe between pump and servo, depending on version, it may have a tee split that also feeds egr vac valve, so check it all out.

Paul.

 

Thanks all. Looks as if it's the none return valve on the booster.