A new crush washer should always be used anywhere they go, oil drain
plug included, as the washers harden and then are prone to leak.  Too
often, folks try to overtighten them to get a seal.

That said, when a new crush washer isn't available, you can anneal the
old one (soften it up again) by placing it on a brick or some such and
heating it to red hot.  You can either let it cool naturally or by
quenching and, because it's copper, quenching will not harden it like it
will steel.  Actually, quenching will keep down the oxidization.

Mike

Michael Sullivan wrote:
> Hi, All.  When I pulled the high pressure switch, I also removed the bushing
> to the block.  I cleaned both  and reinstalled bushing(old w/copper washer),
> then the new switch. Put on the laternator belt and tested for leaks and
> seems I have one.  Will remove switch and bushing again and wanted to know
> if new crush washer needed on bushing. Want this DONE. Will remove belts
> again as I replaced w/new 1 hour ago and easier to reach switch.
> BTW-24mm deep socket and thin 1/2 drive and switch is OUT! No bending and no
> muffler probs.  Really easy with belts off.
> Please advise opinions ASAP. Thx.