Leaky fuel pump gasket?

[TheJWT]

I have a fairly infuriating problem with my Suzuki in that ever since I replaced the fuel pump, the gasket won't seal and it leaks fuel everywhere. It originally had an all rubber gasket that actually got recalled back when it was new. That one leaked, and I replaced it with the new metal/rubber hybrid one and it leaks just as bad. I tightened the bolts in the correct order to the correct torque setting according to Suzuki and no luck...

Here's what the fuel pump assemble looks like-

And this is the gasket that goes between it and the fuel tank-

The lip on the gasket sits in a channel on the fuel tank to keep it on place.

I'm hesitant to tighten the bolts more, all of the literature from Suzuki stresses not overtightening them. They recommend 35 in-lbs. though which doesn't seem like much.

This is the PDF issued by Suzuki detailing the recall for reference-
https://www.sportbikes.net/attachments/asmc_002631-pdf.107543/

[beefchips]

@TheJWT the fact that two new gaskets both leak makes me think that there is some crud on your tank or on the pump base that is preventing the gasket from sealing properly. Maybe clean both surfaces really well and try again?

35in-lb is very little but if the surfaces are good that should be enough to generate a good seal with a rubber gasket.

[TheJWT]

@beefchips The tank was rusted when I got the bike (I've had it cleaned out since) so that does seem likely. There is a bit of surface corrosion on the pump base

[benjrblant]

I'll second @beefchips about the surfaces being clean. It's not likely, but does it also call for form-in-place-gasketing (FIPG) on the seal?

[ItalianJobR53]

@thejwt I would stick with the factory torque spec...overtightening gaskets can also make them leak in my experience

[ClassicDatsunDebate]

@thejwt
First of all, the "New" cross section in the TSB looks to be deceiving, because it shows the lower gasket protruding INTO the fuel pump plate....which it wont because the plate looks flat. I HATE uncaptured gaskets in any design.
That looks like a very finicky gasket to get right. I see the gasket to tank interface has a home in the rolled lip around the tank hole. The bottom part of the gasket that pushes up against the fuel pump mounting plate doesn't have a groove? That's what it looks like to me. That means that it is completely reliant on how flat the fuel pump plate is to provide consistent squish around the full circumference. Also, if you over torque it or unevenly torque it, it could slide on the plate and roll over or move...just based on the TSB and pics you provided.
I would make sure everything is spotless and that the fuel pump plate is perfectly flat. Other than that, do the two step torque procedure and hope for the best. all while working upside down.

[TheJWT]

@benjrblant It doesn't, but I was thinking of resorting to that if I can't get it to work on its own.

[CivicWagonEngineer]

@classicdatsundebate said in Leaky fuel pump gasket?:

do the two step torque procedure and hope for the best.

Ya I think doing a stepped torque sequence on all the bolts will help keep the gasket in the right spots

[Exage03040]

There's also the possibility that the pump mounting plate (or less likely, the tank) is warped if the mating surfaces are clean.

[pip bip]

@thejwt sealant?