coilovers and bumpstop washer

Trying to reassemble my gaz coilovers after getting them refurbished however I can't get ahold of a bump stop washer to go between the rod and top mount. Im lead to belive that not having this washer in will cause the rod to puncture through the top mount , not ideal especially as this will be for track use so will be under alot of force

the part number is egp1706 however rimmerbros are out of stock as are the two other sites that list the part. The Honda version is also apparently unavailable so would it be possible to use a similar sized penny washer or is the metal not strong enough ?

from the last news http://ift.tt/1bNhw4I

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