Suddenly won't start after recent tandem pump change

The Jubilee clip does not apply even pressure onto the pipe due to the shape of the clamp. This is more visible when you remove a Jubilee clamp that has been fitted for a while. you find a deep indentation where the thick part that hold the worm gear screw has been sitting. This is the area of most pressure on the pipe. The spring band clamps when removed have the same depth indentation all around the clamped surface. The Jubilee clamp can easily be over tightened where as the spring band clamp automatically sets its tightness as long as the correct size is used for that pipe.

It is worth noting that the older canister type fuel filters did not have a problem with trapped air. The later plastic housing filters can even after years of use still have a small amount of trapped air inside them.
 
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These would be better than jubilee clips then
 
That's exactly the set I've got but I find that the grip isn't very good on the original tubing.
Probably because they have the indent from the original clamp
 
The original tubing is by now probably compressed and stiffer than new. That said the original Audi clamps are better, I much prefer them if I can get them.
I've been looking for those types of clamp.
There seems to be two types, the pex clamp that you squeeze with pinchers or the other type that are completely flat
 
Hope I'm not speaking too soon, BUT.. it looks like I may have sorted this starting issue on my TDi.... replaced the old hard top fuel hose, and used the spring clips rather than jubillee clips, also cut the end off th lower fuel hose and re-seated it with a spring clip. Car has now started first click when left overnight a couple of times!
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The Jubilee clip does not apply even pressure onto the pipe due to the shape of the clamp. This is more visible when you remove a Jubilee clamp that has been fitted for a while. you find a deep indentation where the thick part that hold the worm gear screw has been sitting. This is the area of most pressure on the pipe. The spring band clamps when removed have the same depth indentation all around the clamped surface. The Jubilee clamp can easily be over tightened where as the spring band clamp automatically sets its tightness as long as the correct size is used for that pipe.

It is worth noting that the older canister type fuel filters did not have a problem with trapped air. The later plastic housing filters can even after years of use still have a small amount of trapped air inside them.
Understood.
If there is room you can use two jubilee clips side be side and 180 degrees apart when tightening will normally stop leaks.
 
the clip in the middle picture is fitted incorrectly, it looks like the clip is deformed to an oval shape, you can clearly see in the picture that the top of the pipe is not being clamped

Paul
Well I will remove it and try again then.
And they are the correct size.
 
the above clamps look OK, however they are VERY subject to how they are installed,
By design they do not have a large clamping range, the part that is nipped together is never meant to be totally sqeezed together, also when the sqeezing is done the clamp should still be round, not oval

Personally I much prefare the spring steel type clamps especially on small diamter pipes like fuel pipes. The type I mean are unclamped by using a tool like pliers to squeeze the clamp ends together, you then position the pipe and release the pliers and the spring clamp does its stuff. That type of clamp always remain round and applies a consistent equal force on the pipe all the time, so even if the rubber pipe compresses over time the clip always keeps it clamped and leak free.
See the third picture above for the spring type clamps I'm talking about
The problem is buying these types clips, as they are difficult to find

Paul
 
Mr Fartbox, did the car start ok after the new pipe and clips??

As per my previous post, I did speak too soon and the car is back to taking a while before it fires up!!
All a bit frustrating, seems after disturbing the fuel pipes it works for a day or 2, was the same when I replaced the tandem pump.. twice.
 
Mr Fartbox, did the car start ok after the new pipe and clips??

As per my previous post, I did speak too soon and the car is back to taking a while before it fires up!!
All a bit frustrating, seems after disturbing the fuel pipes it works for a day or 2, was the same when I replaced the tandem pump.. twice.
Yes it did but I made sure that I pumped fuel into the tandem pump using a hand pump.
So with the pump primed I turned the key and she spluttered into life and runs nice and smooth.
I've yet to try her again after sitting overnight.
I'll report back later.
 
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