Many of us owning Jag x308 series cars should check for leaks at brake booster vacuum line connection into throttle body adapter.
This large vacuum line frequently will have leaks, especially if your car has high mileage or has had cooling system problems. Not easily noticed. Vacuum line is large and connects beneath throttle body. This vacuum line is only held pressed to a rubber "o" ring within the throttle body adapter to intake manifold. Hot engine = loss of flexibility in rubber seal at tube end.
if you have a leak... only available part is shown in s-type & x-type parts catalogs (x200 & X400). C2S15816 vacuum line conector kit, consists of 2 pieces & 3 parts. "o" ring is principal part needed. However, "o" ring necessary is found within press-on brass bushing. Good luck.

 

Good advice! I have owned three X308s and all three were leaking at the brake booster/throttle body connection when I bought them.

I bought that kit and fixed them but I couldn’t figure any way to do it without removing the whole throttle body assembly, so that’s what I did...

 

great photo from Jim Lombardi of part for our x308 series jaguars. Part is in catalog for x200 and x400 series cars

Great picture of the odd fitting and O-ring from Jim Lombardi (Sure wish he would post more too!). He came up with the part number and that's great because the JEPC does not list this part separately and I was told you had to buy the entire induction elbow from Jaguar!

https://www.jaguarforums.com/forum/a...1&d=1441731734

 

when i changed mine out on my x type the first time i went with the real o ring and it deteriorated alsmost right away vacuum leaks came back within 6-8 months i then bought an assortment of random o-rings from the brand dorman at the auto parts store and that $.10 cent o ring is still working almost 2 years later very firm snug and strong moral of the story dont buy the jaguar gaskets they fail all the time get good aftermarket gaskets fel pro and others these brands specialize in the gasket business and are often 10x stronger and better quality then oem

 

It’s not only the o ring to be concerned about, that plastic lock I wish could be sourced from somewhere other than a dealer. I wonder if grainger would have that….

 

Does AMAZON deliver to you?

Genuine Jaguar C2S15816 - Brake Booster Kit

 

they’re john guest plumbing fittings

8mm or 3/8 i forgot

the big one on the xf sv8 is 12mm