I have a 1959 Mark 1 with HD 6 carbs ( although with a 3.8 L engine installed). I keep this car in Utah at my second home. Anyway, I was away for about 8 weeks returning just now. I started the Jaguar this morning and thought I'd go for a short drive, but about a block away from home, I smelled gas ( this had never happened before ) pulled over but kept the car running, looked underneath to discover a steady drip of gas emerging from the front of the car. So, back to the garage. Leak was coming from the banjo connection to the front float bowl cover. This hadn't been a source of a leak previously ( and nuts USUALLY don't come loose by themselves when the car is just sitting in the garage). Anyway, my thoughts are that something is amiss inside the float bowl ( sunken float / bad float needle ) OR the breather pipe has become plugged which may have increased the pressure inside the float bowl and forces the gas out from the banjo connection. Gentlemen, am I on the right track of diagnosing this issue or is there another obvious explanation ?
THANKS !

Schmitty

 

You are on the right track. Replace the thick fiber gasket on the banjo bolt with a new one. They don't last forever.

 

Glyn, just what I've been thinking for the last hour. I'll put on the aluminum one that I bought last year.
Thanks !

 

fiber can dry out, shrink and crack. it needs refreshing with the liquid it's meant to stop from leaking. aging exacerbates the tendency. eight weeks is probably enough for it to affect a 1959 carb.

FYI. IME, if the proper array of washers of various substances, stacked in the correct order is not maintained on those banjo joints, there's little chance of stemming the tide, so to speak. even if done properly, it can be a bear to get the joint to seal properly. what i'm saying is don't be disappointed if it doesn't work with just the aluminum washer (although i hope it does, of course!)

 

I would go with the fibre washer and a bit of grease so it seats properly.
Using aluminum on aluminum may gall the carburetor surface.
Maybe copper would be better with grease.

 

Well I've got both types of washers so I can go with either one.k I had thought that the aluminum ones were supposed to be better. I do like the idea of some grease on the fiber ones. If I had some kersone, I'd soak the fiber ones in that for about a day and then use them.

 

Fiber washers require to remain damp. Grease & gasoline are ideal. Grease surface & you will have gas internal.

 

So, it turns out on dismantling that my carbs do NOT have the float chamber filter. It has run just fine without them.... so , are they really necessary ?? the car has an inline fuel filter before entering the feed pipe to the carbs.

 

That's all you need.

 

I have always used fibre washers. Alloy never worked for me.
Just pre-soak them in any petrochemical handy such as kerosene, diesel, petrol (gasoline) for a day or so to soften up the surface.

By the way if you are using old copper washers string them on a piece of wire heat them up to red hot and then dunk them into cold water.
That anneals (softens) the copper so it will conform to the sealed surfaces. Useful on cam covers and anywhere used to seal fluids.

 

I didn't have any luck with the alloy washers either. Installed the fiber ones. Next time, I'm following Bill's advise and soaking 'em in petrol for a day or two before installing.
Thanks everyone for your help with this issue.
Schmitty