Are the speed bleeder screws longer than the OEM bleeder screws ?
If they are the same length, the sealant on the threads is probably the issue .
Find these on the 737's I work on, usually in the cabin interior furnishings, the screw/bolt is usually threaded into a 'soft' metal, aluminum or brass like material .
The sealant binds the fastener up, until the threads give way .
I would personally run them through a die before installation to clean the threads up, if you wanted, you can add a wrap or two of teflon tape afterwards, on the upper portion of the threads to seal them during the bleeding process .