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Old 08-02-2011, 06:12 AM   #15
davegaz OP
Joined: May 2007
Location: Chandler, AZ
Oddometer: 58
Originally Posted by JStancampiano View Post
Looks like yours may be leaking fron the flange itself. Mine leaked from the cracked fitting, but my flange has small radial cracks similar to yours. The Yamabond was used to seal the threads on the new brass fitting. This is a totally wrong place to use a tapered pipe thread because of the weak plastic flange. It looks like ours were overtightened from the factory, causing the cracks. I hate to spend the $300 on a new flange, but even though it's holding now, I don't trust it.(on the 07 GSAdv plate is listed separately from fuel pump). This is one of those parts that should never break within reasonable life of cycle. Try for warranty repair before you fix anything.

Agreed. My experience with NPT connections is to never use a female thread in a plastic part. The hoop stress is fairly high and one can easily crack the flange by over-tightening it. I think the case here may be that, over time, the flange material degrades from contact with oxygenated fuel until it cracks under the original assembly stress. What's more is that the pump flange sits almost directly downstream of the oil cooler too. Summertime riding in Phoenix certainly can't help the situation.

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