Servo one way valve?

[Blakefruid]

Happy sunny morning to all!
What a day to be out under the bus!
I'm replacing the vacuum pipe from the Servo, but there isn't a one way valve (black & yellow VW 191 611 933)- should there be one? I have a stock ATE servo.
Cheers,
Blakie

[itchyfeet]

see diagram here, looks to me like the diesel doesn not have one, probably because it's fed from a pump rather than the engine manifold

8 is petrol 10 is diesel

https://volkswagen.7zap.com/en/rdw/typ+ ... 611-67000/" onclick="window.open(this.href);return false;

[colinthefox]

The non-return valve on a diesel is integral with the vacuum pump on the engine.

[Blakefruid]

Thanks very much.