Thought id post in here because the fab vrs is the one with most pd130 engines in.

 

I have an issue - its my new passat but could do with a hand.

 

i had a vac leak, so replaced and simplified my system, all i have now is brand new silicone pipe from vac pump to non return valve to n75 to actuator, and the system is air tight, the master cylinder pipe too is very good.

 

breaks are good but get better as i drive, and when i stop the engine i still have them as you would normally before they fade as pressure goes down. However it is very fleeting - after 5 minutes stopped with no brakes applied, the system loses all pressure, and it starts from scratch again.

 

could the tandem pump leak vacuum? seems slow to pressurise and eager to lose it once it is.

 

Thanks chaps dont wanna buy one unless its necessary. Fuel supply seems top notch

"simplified"  may be your problem--have you bypassed the vac reservoir  (sphere) ?       the vac pump already has one none return valve  the chunky part of the main connector which is often "loose" but I don't think is important      -----think there is another nrv further along with a small "t" off    part of the brake vac line   from memory!!!!!!!!

nah this simplification is very common in the vw world, and has gotten rid of all of my vac leaks. yes the sphere is disconnected but even when connected it was losing pressure still, the sphere is for the ASV etc

 

My golf is the same, with same simplification and there isnt a pressure drop. the nrv you speak of is present

So is it possible for the tandem pump to leak? could it be the 'chunky' one right by pump you speak of?