Compact Dual Circuit Remote Brake Servo

[Purplemonsta]

Hello

Does anyone have one of these fitted?
I fitted one a few years ago and now have an issue that puts the brakes on full when the engine is running (remove the vacuum feed & brakes work normally - all be it unassisted)
Has anyone else had this issue - or has an idea what might be causing it?

Thanks in advance

 

[radish]

I don't know if this is the cause but worth replacing to find out or contact VWJIM and ask him

https://www.alanhschofield.com/ourparts/prod_3034812-Brake-Servo-One-Way-Valve-6879-191611933.html

 

[Purplemonsta]

Already got one fitted Radish
Been in touch with Jim & we reckon a valve has got stuck - he's trying to find a diagram of the system so i can try to strip it down and see what's what

Left it on the van just now & bypassed the vacuum connection