[Hellz]

i doubt it is your UCA that is bottoming out.

there is basically no stopper for the UCA going upwards.
if you disconenct teh UCA from teh spindle, you can raise the UCA all the way up.

downward wise, there is a bump stop there. so your travel is limited.

but if you are going over a speedbump, your UCA will be traveling upwards.

Now, there should have been a plastic bumpstop that should have been installed on the UCA when it was put in. this is a little plastic circle that will prevent the UCA from bumping on the frame.

first thing i would do is check to see if it is there.