Don't risk damage to your truck, your cover, yourself or a family member. Tonneau cover lift supports are inexpensive and easy to replace.
Simply measure your current strut extended from the center of the lower attachment to the center of the upper. Most struts are ball and socket and simply pop off.
To order the proper lifting capacity look on the strut itself for it's rating in lbs.
It's recommended that you replace both struts to avoid uneven lifting and twisting that might damage your cover or hinges.
Caution: Support your cover with a solid rod before removing any lift supports.