I have mounted the wall plate and hangers. After installing the TV onto the wall plate I was adjusting the tilt angle and noticed that it would slide along the wall mout nt with little resistance. Is there a way to stop it from sliding along the wall plate?
The installers told me that it is designed to move backward and forward so you can place the tv where you want it but the mount can be right over the beams.
Can I lower the tv once the wall mount is installed? since the tv is a little too high. Is it possible I can fix the problem without making too much mess?
Depending on the size of your TV and how far you want to adjust it it is possible. The brackets that attach to the back of the TV have several holes, you can adjust the height sightly up or down by using other holes. This gives you about 2" maybe 3" of adjustment range. If you need to go further then the only way is a big hassle moving the mount plate on the wall.
Unfortunately it's measure twice, cut once. The only way to lower the TV after the mount is installed is to reinstall it lower. There isn't much else you can do about that.