I guess you mean when you press the pedal the foot on the bottom doesn't hold it and the whole hi hat starts to lean towards you?
To fix this there should be a big thick washer under the hi hat which keeps the feet rigid when the wing nut under the hi hat is tightened. If this is missing and you only have the nut you will need a new washer.
Hope this helps.
Lest
October 2008
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