Probably released in the 80s, orange red cover (hardback) with a picture of a treaded vehicle in an underground cavern. It's quite a long book that chronicles the adventures of a group of boys in a reform school who are forced to journey (via a large treaded vehicle) into an underground land to recover a magic artifact that the faculty of the reform school want to possess. The underground adventure is the middle portion of the book, the beginning describes life at the school and the third act takes place after they recover the artifact and escape the school.
I read this book a few times as a kid and it stuck with me; enough so that I tried figuring out what it was recently and am now stumped. The only thing I can find through Google search is another person who has tried to find the book on several other forums, with no success: here's the relevant goodreads thread
I'll quote the goodreads thread, since it is a very close match to what I remember of the book (I'm not the original poster of this though):
"I am looking for a YA sci-fi/fantasy book I read when I was a kid. I beleive it came out in hardcover in the US in or around 1988. It was about 12 boys sent to a military/reform school, I think the school was called Kah Nagallah or something like that. I seem to remember that the story was told from the POV of a boy who was being sent to the school with his adopted brother, who was autistic. The faculty trained secretly trained the boys to go on a mission to a subterranean kindgdom to retrieve a powerful object, I think it was called the Vroon. The boys started calling themselves 'the Coyotes' and their symbol was a nautilus shell with an arrow through it. The boys escape the control of the faculty and recover the Vroon for themselves and use it for good.
The book was long, over 300 pages I think. It had some b&w illustrations. The cover art was a drawing of the boys riding in a tracked vehicle with a dome through a cavern. "
"-The faculty at the school used military ranks, most wre Captains. One was named Al Smear, who tries to help the boys later in the book but is killed.
-During a class at the military school, the autistic boy (named Don, I think) takes off his clothes and starts spinning around for no reason.
-During the first part of their mission to the underground kingdom, the faculty make them wear collars that are two way radios, and also shcok collars. Every morning the faculty would wake the boys up by making the collars give the boys an electric shock.
-Later, the boys find a cavern filled with hard cyrstals, possibly diamonds, that are very sharp. they use these crystals to cut off the collars.
-When the boys do find the underground kingdom, they are told they can have the Vroon if they can defeat the enemy of the friendly underground dwellers. I think the enemy was called the Mord. The Mord was a machine that boradcast some kind of evil that would harm or control anyone who came near it. It was a series of 12 large metal disks that were connected by 2 loops of cable. the boys defeat the Mord by getting in the center of the circle, unscrewing the cables from their mounts and crossing them. this makes the Mord eventually explode.
-When the boys return, the narrator contacts his parents. They have been missing for weeks, and the boys make up a story about where they were, and how they were abused by the school faculty. No one can find the faculty, but some of them are trying to get the Vroon back from the boys. The narrator's parents adopt the boys who are oprhaned, or whose parents can't/won't take them back.
Its crazy that I can remember so many of these details but not remember the title or author. Any help would be appreciated! "