Erm whats this bit????

Noticed a bit of hissing in the engine bay earlier, turned out to be these 2 vacuum pipes and the joints had split.

Cut them down and pushed them back on but what are they for?

Haynes manual is pretty useless sometimes

www.cabby-info.com HVAC or Engine Vacuum diagrams.

One is usually plugged off, the other goes to the vacuum reserve through a check valve and a T line to power a/c servos.

If both were leaking it causes your engine to run funnily, and your brakes don't work as well as that is the main vacuum line to your booster.

I followed one to a t-piece at the front of the engine where it had completely come off.

Hopefully I've cured my high idle