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MG MGB Technical - Fuel pump fitting leak - different banjo fittings?

I have 2 SU fuel pumps. The nicer of the 2 has flat surfaces where the banjo fittings attach (see photo). The other (currently on car) has a slight raised edge where the fittings attach.

The problem is the pump pictured leaks badly at the banjo fittings, even with new sealing washers. The banjo fittings have a recess on one side that holds the sealing washer, I have that toward the bolt head.

With the old pump, I have rubber o-rings on the pump side of the fitting and no leaks so far.

I would rather use the better pump, but can't figure out why it leaks. I have 1/4" rubber fuel line on the fittings, it's not a super tight fit but that's not where it's leaking.

Are there different types of banjo fittings?

Thanks! David


David Steverson

David - Have you tried really reefing on the banjo bolts? The pumps with the older style of ports (without the 'O' ring grove) require considerable torque to make a good seal. The sealing surfaces on the inlet/outlet ports on you pump look to have some damage on the surfaces, particularly the inlet port. When I get a pump with that kind of damage to the sealing surfaces, I file them down to a nice smooth surface, but it takes a good file designed for aluminum and a steady hand to keep the surfaces square to the threads. You might try a bit of gasket sealer on the sealing surface (I would use hylomar) and then really torque the bolts down quite hard. Cheers - Dave
David DuBois

I'll second Dave's comment re the file. And, I soak the fibre washers in oil for a day, and use Lubriplate on the threads and the bolt head shoulder. works every time.

FRM
FR Millmore

The raised edge does look like it has been pulled up by the threads on tightening, hence the filing. The same happens on cylinder blocks with the head studs.
PaulH Solihull

It turns out that bit between the 2 sealing surfaces was the culprit. On one fitting it interfered ever so slightly. Thanks to Dave for mentioning that!
David Steverson

This thread was discussed between 30/12/2010 and 01/01/2011

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