[T3] Oetiker clamps?

[Jim Adney]

Even tiny fuel leaks are annoying and always worth chasing down and fixing.

For the large gas tank filler hose, you need to make sure that you have the 
wide "rubber band" seals under each end. I've never seen that large hose 
deteriorate, but others have reported it so it must be possible.

For the 5/16"/8 mm hose, it's important to get the connections sealed right 
from the start, because some of the cheaper hose comes with an inner tube 
that is compatable with gas but an outer jacket that is not. So a leak there 
will damage the outer jacket. This may, or may not, be reversible when the 
leak is gone and the outer layer can dry back out.

If you're using the usual worm gear hose clamps, it's important to not 
overtighten, as once the outer jacket starts to extrude thru the slots in the 
band, the hose is ruined. And, note that the smallest sizes of worm gear 
hose clamps come with a "buckle" that is curved to match the hose 
curvature. If you use a clamp that is for a larger size, the curve of the buckle 
will not match and sealing becomes difficult.

The 2 long steel fuel lines that run thru the car are simple straight cylinders 
at each end, making them harder to seal than all the others, which have a 
bulged portion that usually makes sealing trivial. On connections over a 
bulged tube, install the hose clamp BEHIND the bulge, not over it.

I've also had trouble getting the cylindrical connections to seal, even with 
Oetiker clamps. The Oetiker clamps are particularly suceptible to causing 
the hose to lift under the pinch ring, so they are hard to install successfully in 
many cases. I don't tend to use them in most places. The solution that I've 
found that always works on the cylindrical connections is to use the nylon 
snap clamps that have the little teeth that click to the appropriate tightness.  

I have good hose and all 3 kinds of clamps if you need them. I've never tried 
to find a supply of the nice OE style of FI hose clamps. I would have 
expected them to work, but they are just too expensive. They have the 
advantage of full 360 constraint, but so do the plastic snap clamps, which 
cost 1/6 as much.

Jim

On 12 May 2017 at 20:40, Daniel Nohejl wrote:

> Over the past two months or so, we chased down a number of fuel leaks in 
our ´69 Squareback. First, we noticed that both ends of the filler hose in the 
trunk were leaking. The hose was ancient and delaminating inside and we 
replaced it. The smell went away but came back a few weeks later. Turns out 
there was also a leak on the inlet side of the fuel pressure damper on 
account of a loose clamp¦.so loose tha fuel was dripping to the ground. 
Snugged it up. A week later the smell came back and it turns out this clamp 
was loose again. Replaced it. No more leak. Fuel smell returned. Found that 
the outlet side of the fuel pressure regulator was leaking at the clamp. 
Trimmed the hose and replaced the clamp. No more leak. Fuel smell 
returnd. CouldnTMt find a drip or anything anywhere. After a few days, we 
decided to look at the where the fuel lines connected to the nipples in the 
frame up front. Dry. In the rear, they were wet but not quite dripping. 
Tightened the clamps back up (got a bunch of turns on one of them) and no 
smell all week long for the first time in  good two months!
> 
> This was all with 5/16" FI clamps. 
> 
> So would Oetiker clamps be a better idea all over the car or are they only practical/desirable in certain locations? They´re not terribly easy to get off, but how often do they need to be replaced? Is it possible to use the clamping tool in most locations or is it too big restrictive? Just curious....

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Jim Adney, jadney at vwtype3.org
Madison, Wisconsin, USA
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