Xtreme Xpedition Body Mods

(NARRATOR)>> BY THEMSELVES STEEL AND ALUMINUM ARE GREAT METALS FOR BUILDING A RIG. TOGETHER THEY CAUSE RUST. TODAY ON XTREME OFF ROAD WE CUT THE CORROSION ON THE LAND ROVER EXPEDITION RIG, MAKING OUR D-90 BODY STRONGER AND SAFER. PLUS IT'S EASIER THAN EVER TO PLAN A BIG TRAIL RIDE THANKS TO SOCIAL MEDIA, AND BUMP STOPS DON'T JUST LIMIT SUSPENSION TRAVEL. THEY ARE A CRUCIAL PART OF THE SUSPENSION SYSTEM.

(IAN)>> WE'RE GONNA KICK THINGS OFF TODAY BY TACKLING SOME OF THE BODY MODIFICATIONS THAT WE NEED TO TAKE CARE OF ON OUR LAND ROVER D-90 PROJECT. NOW THE DEFENDER SERIES BODIES HAVE A RATHER UNIQUE CONSTRUCTION, AND WE'LL GO THROUGH THAT AS WE START CUTTING ON THIS BODY. RIGHT NOW IT IS LITERALLY JUST SITTING ON TOP OF OUR JEEP JK FRAME. SO THE FIRST STEP IS TO ACTUALLY MOUNT IT IN PLACE. NOW EVEN THOUGH THE D-90 IS VERY STOUT IN STOCK TRIM I THINK WE HAVE MADE JUST THE RIGHT NUMBER OF CHANGES. AFTER SPENDING A LITTLE TIME IN THE DIRT WITH OUR DEFENDER WE KNEW WHAT WE HAD TO DO. WE NEEDED MORE POWER, BETTER SUSPENSION, LARGER WHEELS AND TIRES, AND LOCKERS FRONT AND REAR. SO THE ENTIRE CHASSIS WAS PULLED OUT FROM UNDER THE D-90 AND REPLACED WITH A TWO DOOR JEEP JK FRAME, JKS FOUR LINK SUSPENSION, ONE TON AXLES, AND 37 INCH TIRES, FOLLOWED BY A CUMMINS TWO POINT EIGHT LITER FOUR CYLINDER CRATE DIESEL ENGINE AND MANUAL TRANSMISSION. THE DEFENDER SERIES BODIES ARE A UNIQUE CONSTRUCTION DESIGN. THEY USE A COMBINATION OF STEEL AND ALUMINUM TOGETHER. YOU BASICALLY END UP WITH A STEEL EXOSKELETON, OR STRUCTURE, AND THEN ALUMINUM PANELS MOUNTED TO IT. THAT'S WHY WE WERE ABLE TO COMPLETELY REMOVE THE FLOOR BOARD AND TRANSMISSION TUNNEL WHEN WE DID THE DRIVETRAIN SWAP. NOW THE IDEA BEHIND THIS SETUP IS ACTUALLY VERY SMART BECAUSE THE ALUMINUM, OBVIOUSLY, ISN'T GONNA RUST AND IT'S GONNA BE A LOT LIGHTER. THE PROBLEM COMES WITH TIME. IF YOU HAVE DISSIMILAR MATERIALS, LIKE ALUMINUM AND METAL TOGETHER, TOUCHING EACH OTHER AND THEN YOU ADD WATER THEY ACTUALLY CORRODE FASTER, AND THESE LAND ROVERS WERE NEVER REALLY KNOWN TO BE THAT WATER TIGHT. THAT'S WHY WE HAVE A LOT OF RUST IN KEY AREAS. THIS FLOOR BOARD PANEL IS PART OF THIS EXOSKELETON STRUCTURE THAT'S HOLDING THIS ENTIRE BODY TOGETHER. IF IT STARTS TO ROT OUT WE LOSE THE STRENGTH IN THE BODY. NOW INSTEAD OF JUST REPAIRING IT AND PUTTING THE ALUMINUM PANELS BACK IN PLACE I HAVE ANOTHER PLAN. SINCE I HAVE TO BUILD A NEW TRANSMISSION TUNNEL AND CHANGE THE INTERIOR A LITTLE BIT, I AM GOING TO REMOVE ALL THE ALUMINUM, WELD IN AN ACTUAL FLOOR INSIDE THIS TRUCK. THAT WAY I WILL GET SOME STRUCTURE BACK IN THE BODY AND I'LL BE ABLE TO MAKE THE CHANGES THAT I NEED TO. WE'LL START BY BOLTING THE FRONT FENDERS BACK ONTO OUR BODY, ALONG WITH THE RADIATOR AND GRILL SUPPORT, AND THE FRONT GRILL JUST TO TAKE A FEW MEASUREMENTS. THE REAR OF THE BODY IS THEN LOCKED ONTO THE FRAME WITH SOME TEMPORARY PIECES OF STEEL TO KEEP IT FROM MOVING. NOW THAT THE BODY AND FRAME ARE ONE PIECE THE REST OF THE INTERIOR ALUMINUM CAN COME OUT.

WITH THE ENTIRE FLOOR UNBOLTED YOU CAN GET A GOOD LOOK AT THE STEEL STRUCTURE THAT I WAS TALKING ABOUT BEFORE. IT'S BASICALLY THE ROCKER PANELS ON EITHER SIDE AS WELL AS THAT FRONT FOOT WELL. YOU CAN SEE THAT WE ALSO HAD A LOT OF WASTED SPACE IN THIS D-90 BECAUSE THAT SEAT MOUNT WAS JUST BASICALLY A BIG EMPTY BOX, AND NOW I CAN GO AHEAD AND DROP THE FLOOR DOWN AND HAVE IT SIT EVEN WITH THE ROCKERS. NOW THE FIRST STEP IS TO GO AHEAD AND GRIND OFF ALL OF THE COATING THAT IS APPLIED TO THIS ROCKER. THIS COATING IS HERE BASICALLY TO PREVENT THE RUST HAPPENING BETWEEN THE STEEL AND THE ALUMINUM, BUT BECAUSE I'M GONNA NOW PUT A STEEL FLOOR IN THE BOTTOM OF THIS D-90 THIS COATING CAN GO. [ grinding metal ]

(IAN)>> WITH THE ROCKERS GROUND DOWN TO BARE STEEL, A NEW FLOOR SUBSTRUCTURE IS BUILT USING ONE INCH SQUARE COLD ROLLED ELECTRIC WELD TUBING. THIS WILL GIVE THE FLOOR A STRONG SUBSTRUCTURE FOR THE FLAT PLATE TO BE WELDED TO, AND BOTH ROCKER PANELS WILL BE TIED TOGETHER FOR MORE STRENGTH. [ welder crackling ]

(IAN)>> A RAISED SECTION IS ADDED THAT WILL EVENTUALLY BECOME THE NEW TRANSMISSION TUNNEL.

[ welder cracking ]

(IAN)>> THE ONE INCH STEEL IS BASICALLY JUST THE STRUCTURE THAT WILL THEN PUT THE 16 GAUGE FLOOR PANELS ON. NOW I CAN'T WELD IT TO THE BACK OF THE TRUCK BECAUSE THIS PANEL IS ALUMINUM, BUT I WILL BE ABLE TO CUT OUT ALL THESE RUSTY TOE BOARDS AND BEND UP A WHOLE NEW ONE PIECE FLOOR PLATE FOR EITHER SIDE OF THE TRUCK. YOU CAN SEE THERE'S A LITTLE NOTCH OUT THIS SIDE, AND THAT IS BECAUSE THAT IS THE SIDE THAT THE TRANSFER CASE SITS ON. SO I NEED THE FLOOR SITTING A LITTLE BIT HIGHER IN THAT ONE SPOT. NEXT STEP NOW IS BASICALLY TO CONNECT THIS BRACE UP TO THE ORIGINAL TRUCK'S FIREWALL, AND THEN WE CAN START SKINNING IT. [ saw cutting metal ] [ welder cracking ]

(NARRATOR)>> UP NEXT, NOW THAT THE LAND ROVER'S INTERIOR HAS STRUCTURE IT NEEDS SKIN.

(IAN)>> WE ARE ELBOW DEEP IN OUR D-90 PROJECT TODAY REPLACING THE ORIGINAL BOLT TOGETHER ALUMINUM FLOOR STRUCTURE WITH A NEW STEEL FLOORING SYSTEM TO GIVE US MORE ROOM ON THE INTERIOR AND MORE STRENGTH. WITH OUR NEW STRUCTURE IN PLACE INSIDE THE D-90 WE CAN NOW SKIN IT. NOW I'M GOING TO USE 16 GAUGE STEEL. NOW THIS IS A LITTLE BIT OVERKILL FOR A FLOOR, BUT THE NICE THING ABOUT THE 16 GAUGE STEEL IS IT'LL GIVE US BACK THAT EXTRA STRUCTURE THAT I AM AFTER BY REMOVING THE ALUMINUM FLOOR INSIDE THE LAND ROVER. MY PLAN HERE IS SIMPLE. I'M GONNA DO THE FLOOR IN SECTIONS. I'LL ACTUALLY TIE IT INTO THE SUBSTRUCTURE THAT WE'VE WELDED INTO THE BODY AS WELL AS BEND IT SO IT WILL REPLACE THOSE RUSTED TOE BOARDS.

THE 16 GAUGE SHEET METAL IS CUT TO LENGTH AND THEN TRIMMED TO FIT, BOTH AROUND THE NEW TUBING FLOOR STRUCTURE AND THE "A" AND "B" PILLARS ON THE TRUCK.

IT'S THEN DROPPED INTO PLACE TO CHECK THE FIT.

NOW YOU MAY THINK THAT THE NEXT STEP NOW THAT THE FLOOR BOARDS ARE FITTED INTO THE BODY IS TO JUST START WELDING THEM INTO PLACE BUT THAT IS NOT THE NEXT MOVE. IF YOU REMEMBER, WE'VE GOT A PILE OF RUST AT THE FRONT OF THESE TOE BOARDS. WHAT I'VE DONE RIGHT NOW ON THIS SIDE OF THE TRUCK IS BASICALLY JUST COVERED IT UP WITH GOOD METAL. THE PROBLEM WITH THAT IS THE RUST WILL KEEP RUSTING IF YOU COVER IT UP. IT NEEDS TO BE COMPLETELY CUT OUT. THAT'S WHY THE FRAME WAS SO ROTTEN ON THIS PARTICULAR PROJECT. SOMEONE HAD DONE PATCHES OVER TOP RUSTY METAL. THE RUST JUST NEEDS STEEL TO CONSUME, AND IF YOU JUST PUT NEW STEEL OVER TOP OF IT IT'S JUST GONNA KEEP RUSTING AWAY. THAT IS WHY I RAN THIS TOE BOARD ALL THE WAY UP TO THE VERTICAL EDGE OF THE FIREWALL. I'LL BE WELDING THESE TWO PIECES OF STEEL TOGETHER BECAUSE THEY ARE BOTH RUST FREE. SO THE NEXT STEP IS TO MARK THAT FRONT EDGE, MARK THE ANGLE THAT WILL BE COMING DOWN THE SIDE, AND I ALSO NEED TO MARK THE LOCATION OF ALL THE STRUCTURE PIECES UNDERNEATH BECAUSE WE WILL BE SPOT WELDING THESE FLOOR BOARDS INTO PLACE ON TOP OF THE STRUCTURE, AS WELL AS WELDING ALONG THE SEAM. THEN WE'LL HAVE A NEW FLOOR.

WITH THE FLOOR PANEL REMOVED, THE RUST IS CUT OUT FROM THE STOCK D-90 BODY AS WELL AS CLEARANCE CUT TO MAKE ROOM FOR OUR NEW TRANSMISSION TUNNEL. [ saw grinding metal ]

(IAN)>> HOLES ARE DRILLED INTO OUR NEW FLOOR PANEL FOR PLUG WELDS, AND THE FLOOR IS DROPPED IN ONE LAST TIME. FULLY WELDED TO BOTH THE FLOOR STRUCTURE AND THE D-90'S ROCKER PANELS AND FACTORY FIREWALL.

(NARRATOR)>> WHEN IS A JEEP MORE THAN A JEEP?

(JEFF)>> 2014 WAS MY LAST DEPLOYMENT TO AFGHANISTAN. I GOT HOME, WENT THE VERY NEXT DAY, AND BOUGHT A JEEP.

(IAN)>> TIMES HAVE CHANGED OVER THE YEARS. IT USED TO BE IF YOU WANTED TO GET A GROUP OF YOUR FRIENDS OUT AND GO FOUR WHEELING IT WAS AN ELABORATE ARRAY OF PHONE CALLS TO DIFFERENT PEOPLE. MAYBE A COUPLE OF EMAILS, NOTES LEFT ON EACH OTHER'S DASHBOARDS, AND THEN YOU'D ALL ARRANGE TO MEET IN ONE SPOT AND HEAD OFF TO THE LOCAL OFF ROAD PARK. NOWADAYS IT IS A LOT SIMPLER. ALL YOU DO IS THROW A POST UP ON YOUR SOCIAL MEDIA ACCOUNT AND BEFORE YOU KNOW IT 30 OR 40 OF YOUR CLOSEST INTERNET FRIENDS ARE PLANNING TO JOIN YOU FOR A DAY IN THE WOODS. NOW THAT IS EXACTLY WHAT HAPPENED RIGHT HERE IN THE XTREME SHOP. I WAS WORKING AWAY ONE AFTERNOON AND I SPOTTED ON ONE OF MY SOCIAL MEDIA FEEDS A GROUP OF JK OWNERS WERE GONNA SPEND A WEEKEND IN THE DIRT. SO I TAGGED THEM, AND MET THEM AT THE TRAIL.

(JEFF)>> THIS WHOLE EVENT, IT REALLY JUST STARTED AS A FEW OF US HANGING OUT, HAVING A GOOD TIME, AND TALKING ABOUT TRYING TO GET A RIDE TOGETHER, AND THROUGH SOCIAL MEDIA, THROUGH INSTAGRAM, THROUGH FACEBOOK THE WORK JUST GOT OUT REALLY FAST. HERE WE ARE. I THINK WE ENDED UP WITH CLOSE TO 100 JEEPS.

(IAN)>> THE PLACE, ADVENTURE OFF ROAD PARK IN SOUTH PITTSBURG, TENNESSEE, AND IT HAS BECOME WELL KNOWN FOR THE BOUNTY HILL SERIES THAT'S BECOME VERY POPULAR WITH LOCAL ROCK BOUNCERS, BUT JUST BECAUSE IT'S KNOWN FOR HARDCORE HILL KILLING BUGGIES DOESN'T MEAN YOU CAN HAVE A GOOD TIME WITH SOME MODERATELY BUILT TRAIL RIGS, AND THAT IS WHO SHOWED UP. A PILE OF JEEP JK'S WHOSE OWNERS HAVE REAL NAMES BUT THEY'RE BETTER KNOWN BY THEIR INSTAGRAM HANDLES, LIKE "GRAPPLER JK", "CRAWLER JKU", "THAT PIG JEEP GIRL", AND "I CRAWL ROCKS". THEY'VE BUILT A HUGE SOCIAL MEDIA GROUP AROUND ONE THING, HAVING FUN WHEELING IN THEIR JEEPS.

(DIEZEL)>> THE JK REALLY HAS GREAT PICK UP POINTS. THE FRAME WORK IS STRONG. IT REALLY HAS A GREAT BASE TO WORK ON, AND YOU CAN GO MILD TO WILD AND IT WILL REALLY GO WHERE YOU WANT TO GO.

(IAN)>> THIS GROUP DROPPED ME A MESSAGE, VIA SOCIAL MEDIA OF COURSE, TO SEE IF I WANTED TO RIDE ALONG WITH THEM. ALL THE REASON I NEEDED TO GRAB ONE OF MY RIGS AND HIT THE DIRT. WE ROLLED THROUGH A COUPLE OF MY FAVORITES. TRAIL 41, A LONG, ROCKY SIDE HILL PATH THAT PROVIDES A GOOD OPENING CHALLENGE, AND TRAIL 55 AND 60. A TIGHT, TWISTY TRAIL THAT HAS A ROCK GARDEN AT THE BOTTOM AND TWO DIFFERENT EXITS, EASY OR HARD. THERE IS NO QUESTION THAT PEOPLE BUILD JEEPS FOR MANY DIFFERENT REASONS. SOME LIKE THE CHALLENGE OF BUILDING SOMETHING TOUGHER THAN THE MANUFACTURER EVER PLANNED. FOR OTHERS BUILDING A RIG CAN BE A TYPE OF THERAPY THAT HELPS THEM DEAL WITH CHALLENGES. JEFF YURK, AN ACTIVE MILITARY INFANTRYMAN, HAS DEPLOYED MULTIPLE TIMES. AFTER ONE OF THESE DEPLOYMENTS HE BEGAN SOME JEEP THERAPY.

(JEFF)>> 2014 WAS MY LAST DEPLOYMENT TO AFGHANISTAN. I GOT HOME, WENT THE VERY NEXT DAY, AND BOUGHT A JEEP. THE JEEP ENDED UP AS MY OPPORTUNITY TO KIND OF CHANNEL SOME ENERGY FROM A REALLY TOUGH DEPLOYMENT, AND STARTED OUT I WAS JUST GONNA THROW SOME TIRES AND LIFT ON, AND NOW HERE WE ARE WITH "THE GRAPPLER".

(IAN)>> DIEZEL KRENTZ CAN CERTAINLY RELATE TO JEFF. HE BECAME AN AVID WHEELER AFTER A LIFE CHANGING ACCIDENT.

(DIEZEL)>> WELL IN '06 I BROKE MY BACK IN A DIRT BIKE ACCIDENT. BURST FRACTURED ABOUT FIVE VERTEBRAE, AND I WAS PARALYZED FROM THE WAIST DOWN. I WAS IN A WHEELCHAIR FOR A GOOD YEAR, AND ALL THE THINGS YOU WOULD IMAGINE. TRYING TO WALK THROUGH THE SITUATION. THEY PICK YOU UP IN A BIG CRANE AND DUMP YOU ON A TREADMILL, AND MY FEET ARE KINDA JUST FLAPPING BACK IN THE WIND YOU KNOW. SO YOU KNOW, I'VE LEARNED A LOT ABOUT MYSELF AND A LOT OF CHARACTER.

(IAN)>> DIEZEL'S INJURIES MADE WALKING VERY DIFFICULT, AND HE STILL CAN'T FEEL HIS FEET OR LOWER LEGS. NONE THE LESS, HE LEARNED HOW TO CONTROL THE BRAKE AND GAS PEDAL, AND VENTURED OUT ON AN EPIC CROSS COUNTRY WHEELING TRIP.

(DIEZEL)>> I WAS HAVING SOME PROBLEMS WITH LIFE. MAYBE A MID AGE CRISIS, NOT REALLY SURE, BUT I SOLD EVERYTHING AND LOADED EVERYTHING I HAD IN THE JEEP, STARTED TOOLING AROUND. IT WAS ABOUT TWO AND A HALF MONTHS, 13,000 MILES, AND I STAYED IN A TENT. SO I DIDN'T SMELL TOO GOOD, BUT YOU KNOW MOM'S LOVE. SHE THREW MY BUTT IN THE SHOWER REAL QUICK.

(IAN)>> WHATEVER THE REASON FOR BUILDING A TRAIL TRUCK, AT THE END OF THE DAY WHEN THE DIRT HITS THE TIRES, THE REST OF THE WORLD SIMPLY GOES AWAY, AND THERE IS NOTHING BETTER THAN A DAY IN THE WOODS WITH GOOD FRIENDS AND SHARING THOSE MEMORIES ON YOUR SOCIAL MEDIA ACCOUNT. THAT WAY NEXT TIME MORE PEOPLE WILL SHOW UP FOR THE FUN.

(IAN)>> THE LAST TIME WE WERE WORKING ON OUR "BUCKIN' BRONCO" PROJECT WE WERE FINISHING UP THE UPPER SHOCK MOUNTS FOR OUR BYPASS AND COIL CARRIER SHOCK IN OUR TRAILING ARM SUSPENSION SYSTEM. NOW THIS REAR SUSPENSION SYSTEM IS NOT DONE YET CAUSE WE HAVE ONE MORE ITEM THAT WE HAVE TO ADD, AND THAT IS A BUMP STOP, AND ON A HIGH SPEED OFF ROAD CAR LIKE THIS ONE THE BUMP STOP DOES MORE THAN JUST KEEP THE SHOCKS FROM BOTTOMING OUT. IT'S ACTUALLY AN INTEGRAL PART OF THE SUSPENSION SYSTEM. THEY'RE CALLED HYDRAULIC BUMP STOPS. THEY'RE QUITE OFTEN JUST REFERRED TO AS AIR BUMPS BECAUSE THEY ARE ESSENTIALLY A SMALL AIR SHOCK. INSIDE THE BODY OF THE BUMP IS A SET OF VALVES LIKE YOU'D FIND IN A SHOCK, A COLUMN OF OIL, AND THEN A CHARGE OF NITROGEN ON TOP OF IT. NOW WHAT THEY DO IS PREVENT THE AXLE FROM EVER COMING TO A HARD STOP AS IT GETS COMPRESSED. WHEN THE AXLES COMPRESS IT WILL CONTACT THIS SMALL PAD ON THE BOTTOM OF THE BUMP AND WILL ALLOW IT TO SLOW DOWN PROGRESSIVELY BEFORE COMING TO A SOFT STOP AND THEN DROOPING AWAY FROM THE CHASSIS. ANY HARD STOPS INSIDE THAT SUSPENSION MOVEMENT CAN TRANSFER INTO THE CHASSIS, MAKE THE VEHICLE FEEL A LITTLE BIT UNSTABLE. THE HYDRAULIC BUMP STOP PREVENTS THAT FROM HAPPENING, KEEPS YOU IN CONTROL OF THE TRUCK WHEN TRAVELING AT SPEED OVER ROUGH TERRAIN. THERE ARE SOME GUIDELINES TO INSTALLING AIR BUMPS INTO SUSPENSION SYSTEMS, SPECIFICALLY WHEN IT COMES TO TRAILING ARMS. DUE TO THE LEVERAGE IN THE SUSPENSION SYSTEM, ON A TRAILING ARM CAR YOU NEED A LARGE AIR BUMP, LIKE THIS TWO AND A HALF INCH BUMP FROM ADS SHOCKS. DESIGNED TO WORK HAND IN HAND WITH THEIR SHOCK PACKAGES, THIS BUMP IS VALVED TO MATCH THE VALVING IN OUR BYPASS SHOCK TO PROVIDE FULL CONTROL OVER OUR REAR AXLE. YOU WANT AT LEAST 10 INCHES OF TRAVEL BEFORE THE AXLE CONTACTS THE BUMP. SINCE WE HAVE 26.5 INCHES OF OVERALL WHEEL TRAVEL THAT'S NOT GONNA BE A PROBLEM FOR US. THE PAD ITSELF ALSO NEEDS TO BE LARGE ENOUGH TO CATCH THE BUMP STOP WHEN THE AXLE ARTICULATES BECAUSE IN AN ULTRA FOUR STYLE CAR THE AXLE DOESN'T ALWAYS TRAVEL STRAIGHT UP AND DOWN. [ torch cutting metal ]

(IAN)>> NOW THE WAY I HAVE THIS BUMP PAD BUILT RIGHT NOW IT'S RAISED UP HIGH OFF THE AXLE TUBE SO THAT THE BUMP IS FULLY COMPRESSED RIGHT DOWN TO THE ORING BEFORE THE SHOCKS BOTTOM OUT. THAT HELPS PROTECT THE VALVING IN THE SHOCKS. NOW THIS BUMP PAD WILL SEE A LOT OF ABUSE. SO I CAN'T JUST LEAVE IT AS THIS THREESIXTEENTHS INCH PLATE HERE. I'M GONNA HAVE TO ADD SOME GUSSETS ON THE INSIDE TO BASICALLY BOX IT INTO PLACE. THEN I WILL BE ABLE TO GO AHEAD AND FINALLY FINISH THE UPPER LINK MOUNTS IN THIS SUSPENSION. [ torch cutting metal ]

(IAN)>> THERE ARE MANY FASTENERS ON YOUR RIG AND THEY ARE ALL VERY IMPORTANT. A LOOSE NUT AND BOLT IS THE FIRST STEP TO THAT FASTENER FAILING BECAUSE IT PUTS AN EXCESSIVE AMOUNT OF LOAD ON THE SHANK OF THE BOLT AS IT MOVES AROUND IN THE HOLE. THERE'S MANY DIFFERENT WAYS TO ENSURE THAT NUTS AND BOLTS STAY TIGHT ON YOUR RIG BECAUSE A LOOSE BOLT THAT THEN FAILS IN THE WORLD OF OFF ROADING, WELL THAT IS A BAD DAY. A LOCK WASHER IS A SPRING LOADED SPLIT WASHER THAT IS DESIGNED TO DIG INTO THE FACE OF THE NUT AND PREVENT IT FROM BACKING OFF. MECHANICAL LOCK NUTS COME IN A FEW DIFFERENT STYLES. A NYLON LOCK NUT HAS A NYLON RING THAT KEEPS IT FROM BACKING OFF. THEY WORK WELL EXCEPT IN HIGH HEAT AREAS THAT CAUSE THE NYLON TO BOIL OUT. A TOP LOCK NUT IS A NUT THAT HAS THE TOP THREADS PINCHED OVER. THESE ESSENTIALLY CRUSH THE THREADS ON THE BOLT AS THEY TIGHTEN. THE LOCK WASHER WILL HOLD BUT OVER TIME IT CAN LOOSEN OFF, ESPECIALLY IF SUBJECTED TO HIGH HEAT OR CORROSION. THE NYLON LOCK NUT WILL ALSO HOLD FOR A LONG PERIOD OF TIME BUT IF YOU REMOVE IT EXCESSIVELY THE NYLON WILL LOSE SOME OF THAT GRIPPING STRENGTH ON THE THREADS. THE TOP LOCK NUT WILL USUALLY RETAIN ITS STRENGTH NO MATTER WHAT, BUT IF YOU TEND TO USE THIS TYPE OF FASTENER MAKE SURE THAT YOU COAT THE THREADS OF THE BOLT OR STUD WITH SOME ANTISEIZE. THAT'LL PREVENT THEM FROM GALLING WHEN YOU REMOVE THE NUT. ANOTHER OPTION IS TO USE A THREAD LOCKING COMPOUND THAT CHEMICALLY WELDS THE NUT AND BOLT TOGETHER. THESE ARE AVAILABLE IN DIFFERENT STRENGTHS DEPENDING ON IF THE FASTENER NEEDS TO BE REMOVED IN THE FUTURE AND HOW OFTEN. IF THE NUT IS TO BE OFTEN AN OPTION THE OEM'S USE ON A REGULAR BASIS IS A CASTELLATED NUT WITH A COTTER PIN. THIS PREVENTS THE NUT FROM BACKING OFF AND THE NUT CAN BE REMOVED AND INSTALLED MANY TIMES WITHOUT DAMAGING THE THREADS.