OK...your racking the bar on the front delts because your doing cleans or front squats? Sorry, my fault.
Anyway, the triceps will need some stretching if you can not get the elbows high enough (even the lats may need more flexibility in some cases), which is one of the keys of holding/catching the bar on the delts and upper pecs. Try some wrist/forearms movements also. If your into martial arts, there are some outstanding versions of these finger/wrist/forearm exercises/stretches. For triceps, might try bent arm DB pullovers ,working for a light full stretch at the bottom of the lift. Also great for lat stretching. Or something like wall/strap tricep stretches.
Rather than attempting to raise the elbows straight out in front of you, have the elbows points out wider a bit. Will depend on your body structure of course as to how wide the elbows should go. Might even have to play around with the grip on the bar to find what is right for you (as OverLoad suggest). A heavier weight, after a clean, should somewhat settle into the front delts/upper pecs quite well after awhile. Having thicker delts helps a lot. After settled, you should be able to let go of the bar without any fear of it going anyway, if you wish. That is, as long as the elbows are kept in position.
BB'ers will front squats with crossed hands at the middle of the chest, elbows raised. They are not really holding the barin place but allowing it to cradle into the delt/chest area. A few guy's go for the hands free method, and have the arm, bent at the elbows, extended out a bit.
I am not all that tall (6'2) and have a long hand span, so front cleans and catching the bar was a challenge at first. But the more you rep it out the more natural it becomes to clean any weight. Good Luck.