Mk1 coach vacuum pipe leak detection

Hello. We are in the process of commissioning a newly restored Mk 1 coach . The brake cylinders work fine and all flexible have been replaced. We cannot detect any leaks but the train pipe will not hold vacuum for the required amount of time. Has anyone experience of leak detection using a smoke generation machine? if so any advice on this or alternate leak detection methods would be gratefully received.
Thank you
Norman

 

Check the passenger valves, DA valves and vacuum gauge (if fitted).


1. Plug off cylinders and test just the pipework and valves on the coach. Make sure all valves are seating properly, and that the dummy seals are not split.
2. Check vacuum gauge, as I recently had one that was accurate, but had a split tube so wouldn't hold....

 

I'd check the PC valve first, particularly if you haven't overhauled it, as the seals go hard.

Has the carriage been out of service a long time?

Sawdust.

 

Thanks guys. Yes coach has been standing a long time. PC valve is ok , Admission valves have not been overhauled. Going to isolate cylinders and test pipework tomorrow. Guess we just need to keep going through the system.
Good point about the vacuum gauge will change for a spare and see what happens.
Thanks again