I have some tool-less slide rails for some 1ru x4150 sun servers. I can't seem to see how to remove them. Sun in their wisdom did not include this seemingly important information in their documentation; they simply (possibly with a cheeky smile) say to...
"Refer to the (long since lost) installation card included with the rackmount kit for instructions on attaching tool-less slide-rail assemblies to the rack."
So if anyone knows please let me know.
If I assume you are talking about square post hole rack rails, the way to remove them is less than obvious and almost invisible when they are installed in rack.
There are 2 ways to remove them.
The imgur gallery here (http://imgur.com/a/kqA83) shows the spiring loaded tab and the access hole highlighted in red in the first and second images respectively. In the second image it is orientated as it would be for a LEFT hand rail in the rack.