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High pressure union pipes


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Hey gang,

So I want to replace the rocker cover gasket on my MK2 Focus 1.6 TDCI, as well as checking out the oil separator for leaks and replacing injector seals. 

According to Haynes (and a lot of other sources) the union pipes connected to the fuel injectors MUST be replaced once removed. These seem to be rather expensive, and although I've researched the reasons why they should only be used once, it's gonna be looking pretty expensive for the "simple" (and cheap) work I'm attempting.

So, question, is it too much of a risk to re-use the pipes? Is there a way to remove the oil separator for inspection without dismantling the entire manifold including injectors? 

I hope someone can help, cheers, Sam

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I've had the HP pipes off the injectors a few times on the same engine and never had any problems but have taken care to be clinically clean with pipe and injector open ends etc. I think to main reason why they stipulate replacement is that the flared ends are semi "compressible" to make the hp seal onto the injector and common rail and to cover manufacturers backs. I've had all the pipes off when removing the inlet manifold and injectors (can be tricky!) to replace the injector seat washers and injector tube top seals (well worth it if you're removing the injectors). If you're very careful you can just undo the unions at the injector end and gently tie them out of the way with some wire so that you can get the manifold off. Make sure you don't bend or kink the pipes! It's easier if you take the black plastic anti vibration pipe clamps off as this will make it much easier to get the pipes out of the way. When you put the pipe unions back on to the injectors make sure they're perfectly square and undo the injector clamp nuts so that the injectors will rotate to align the union before tightening up.

I threw away the poxy moulded seal in the camshaft cover valve thingy and stuck a length of 5 mm diameter O ring cord in the seal aperture and haven't had an oil leak since. It's a poor design. Don't over tighten the hp unions as this will deform the flared ends and promote leakage - just enough so that you get a dry seal. The whole design of the cam chamber is rubbish from the inadequate injector retaining studs which are prone to tensile fracture to the over complex breather cover. Only thing they got right was sticking the turbo at the front! Good luck!

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