Diesel Pump Leak

[Puppywalker]

Can anyone help? I've a leak around the switch on top of the pump, the weep comes from between the switch and large nut.

what size socket to remove the nut?
is there anything behind i have to watch?
easiest way to seal this?
do I need anything special?

Thanks in advance tony

[Tiger]

Try nipping it up a touch other wise there are a couple of easy seals to change and 1 horrible one. have a look in the 2.4 tech section. good luck