Wilcox and Crittenden deck fill problem

[killarney_sailor]

Our boat has Wilcox and Crittenden deck fills that consist of an aluminum deck fitting with a black plastic screw in plug. One of our diesel fills has seized. I broke the plastic trying to get it open and had to repair it with epoxy. I have tried PB Blaster without success.

The problem is that we are sitting in Suva harbour in Fiji and there is no convenient marine store - especially with imperial-sized fittings. I suspect we can survive until we get to Brisbane in early September but does anyone have a bright idea for getting this plug loose?

[MarkSF]

You can try to take advantage of the difference in thermal expansion between plastic and aluminium.

The aluminium should be 20ppm/C and the plastic could be anything from 25 to 200 ppm/C. (Nylon is 50). That means that cooling the cap and deck fitting might free up the filler cap as the cap will shrink more than the aluminium part.

Try pouring some very cold, icy water over it and see if that frees it up. If you can cool the plastic part more than the aluminium, so much the better.

[Zanshin]

Unfortunately this does seem to be a rather common problem, most often caused by overtightening. I've done it twice (fills had to be drilled out/replaced), assisted two friends without success, and watched a poor soul with a frozen diesel fill have to postpone his departure for Europe from the Caribbean by 2 days since the torque applied in trying to open up the fill tore out the fiberglass mounting screws so that everything around the fill needed to be re-glassed.
In my case I assume that it was metal-on-metal galling and I hope that MarkSF's great advice will help solve the problem. I've learned my lesson and now only tighten the fills just a touch more than hand-tight.

[paul323]

Just an idea - in a similar situation (frozen emergency tiller access), to get more leverage I got a long piece of wood, put in two large nails (with the ends cut off) and used this as a lever/wrench to increase the torque. My problem was holding it in place; once I wedged it is place it did work. So perhaps a combo of ice and a long lever?