Tale of an MOT and a plea for torque

[batwad]

My 306 failed its MOT a fortnight ago on sub-frame mounts, OSF track-rod end and emissions. I took a day off work in the week to sort these bits out (with parts purchased from GSF, natch) so that I could get the old boy in for the free 7-day re-test. I got down there at 8:30 and was the first to be seen, so the engine was nice and warm and I could watch the test. Drove up to the guy to do the emissions test, popped the bonnet and he started attaching sensors when a mechanic over the other side of the shop called out.
"You've got a leak, mate!"
A quick peek under the car, and sure enough a sizeable puddle of coolant is forming on the garage floor. "Bloody typical" I thought. I had a good look around and I could see coolant seeping from the union between the hose and the inlet on the front-right of the cylinder head. I wiggled the hose and it looked like the jubilee clip holding the hose on had worked loose so I thought I'd nip back home to tighten it up and refil the system.
I wish it were that simple. It turns out that there's a plate that bolts on to the front of the head. On NA diesels it's just a blanking plate but on turbos it's got a spigot onto which a hose goes. The spigot on mine had snapped off, quite some time ago before I bought the car I should add, and someone had made a quick fix by inserting a piece of thin copper pipe into the hole left by the spigot, thereby making a new spigot. Quite ingenious, but an horrific bodge really, although it's held for at least a year as that's how long I've had the car.
Now I really needed to get the car MOTed on that day, so I remade the fix by putting some central heating silicone sealant on the copper tube and poking it back into the hole. An hour later it seemed to be holding, so I refilled the system and trundled off to the garage.
It passed! [:D]
Got a replacement spigot plate thingy from the dealer this weekend (£21 please [V]) and fitted it yesterday afternoon. To get to the lower of the two bolts that held it on I had to remove the short metal section of fuel line that goes into the fuel pump. The bolt that holds the fuel line in is some crazy bolt with a hole drilled up the shaft and another hole drilled across the neck. I spent some time looking at it as it intrigued me.
I should have paid more attention. It didn't occur to me that all these holes in the bolt would make it quite fragile, so I overtightened it and it sheared. [:(]
I'm off to the dealer (again) to get a new bolt (£23456245629562 please [:o)]) today and was wondering if anyone here knew what torque setting to use [:)]

[mbunting]

Obviously not as much as you used before !
Seriously, with this sort of thing, I wouldn't get too scientific, and just tighten it until it feels tight.
Presumably there's some kind of seal / gasket ?
Mat.

[batwad]

I think the problem was that it was pretty stiff to undo, so I reckon that maybe it fractured or weakened when I undid it thereby making it more prone to breaking on tightening. At least that's how I explain it to myself [:)]
As for the seal, there's a pair of copper washers that go either side of the union. Should I replace them as with the sump plug, or is it enough to give them a good clean up before refitting?

[fastandfurryous]

Hi.
These fuel system bolts are called "banjo" bolts. This is because the bit it bolts through looks kinda like a banjo. They are a nice design, as it allows you to set the direction the pipe to the injection pump goes. The copper washers will only need replacing if you can't get a good seal (this is rare, they usually seal fine). As for a torque setting.. I have always done these by guesswork, but you shoudn't need much more than a "nip and a bit" to seal them up.
Make sure they are sealed though, as any leakage on the supply side will not show up as a fuel leak: this is a "suction" line, and so air will be drawn into the fuel, and you run the risk of the dreaded XUD surging problem. (although this is a lot less common on turbo models for some reason)
HTH.
David.

[batwad]

Thanks for that, David. What would be the signs of air being drawn into the fuel line, and would they be something I would see pretty soon after putting it back together?

[fastandfurryous]

If you do start drawing air into the injection pump, you'll get poor starting, bad idling, and possibly surging, (big power fluctuations at a constant accelerator setting) If you are even slightly concerned about the copper washers, then just change them. new ones are pence, and they're the same size as the sump one, so you can use the old fuel system ones on the sump as and when you need to.
David.

[fastandfurryous]

No... sorry.. I lied. They are not the same size as the sump copper washer. It's the injector sealing copper washer that is the same size as the sump copper washer. oops!
David.