Early XJ40 fuel line o-rings

Hi all,

I’m struggling a bit with getting the two rubber fuel lines from the fuel rail to the body hard lines connected without leaks. My '88 has the earlier style connections with threaded fittings.

I didn’t see the o-rings called out separately on the parts catalogue but got some Viton o-rings from McMaster in 7.6mm ID, 2.4mm wide that match the dimensions well.

I’ve tried putting the o-ring on the line first and then threading on the hose, and putting the o-ring in the hose bore and then pushing that over the line. Always a small leak. Is there a better technique? A different sized o-ring?


And of course after posting that I retread my past searches and find CBC4720 viton olive on the parts list. NLA from Jaguar, but eBay has some. Fingers crossed.

Anyone know the proper installation procedure for the viton olives? Assume they slide on the pipe until they hit the ridge, then tighten. But I don’t want to screw them up as they are expensive and rare.

Normally, with brass olives, you just slip them over the end of the pipe and tighten them up. The olives compress and make the seal. No doubt these plastic ones work the same way.

Thanks Larry! I am definitely hoping they are as simple as the little brass olives I use on my bicycle’s hydraulic brakes.

Update: I installed my seals purchased from eBay seller “jerryjag”. Here is their advice on installation:

“Jaguar has only made one type of these seals,
if you use them for the V12 fuel injector rail.
The fuel supply hose is thicker and there you put a seal on the pipe and tighten it.
On the other side, the return hose, the tube is thinner and there you have to first put the seal into the hole and then tighten the pipe .This side looks looser, but the gasket seals well.
Please check if it does not leak after installation.
Any questions please ask, I worked in the Jaguar service from the late 80s to 2004 as a Jaguar Master Technician”

I found on my car, the olives were a bit loose on both pipes, so to prevent binding while clearing the threads I seated them within the threaded section first and then slipped that over the pipe and tightened the union. It doesn’t take much force. No leaks so far.