I Also have an 86 K20! I too found it challenging to mount the brackets / tank (new brackets, new tank… both from LMC). I used a large piece of cardboard and some scrap wood under the tank (cardboard for scratching, wood to prevent damage of threaded rod protruding from bottom of lmc straps that hold the fuel tank protection plate in place (I did all this on the ground in my garage btw). Initially thought I could reuse OEM straps, as they were still good, but learned they don’t fit the LMC tank. The lip the runs around the entire lmc tank -on the sides-, I discovered sticks out too far for the straps to fit around. So I took a pair of pliers and had to bend down on both sides of the tank where the straps sit. I then placed the protective “padding” (2 different pieces… one short, one long) in place (short piece obviously goes first. I used a piece of tape to hold the longer piece in place until I got the strap on, (tape kept it from slipping off… be sure to position the seem of the longer protective paper accordingly, as securing the strap around the takes a bit of jolting and the protective paper can shift out of position). If I could do it over again, I would try to find a piece of rubber or some kind of sticky membrane (not quite sure what would work best) to place between the tank and the strap. Tho what LMC provides may be more than sufficient to protect the tank, I can’t help but think that water -in time- will find its way in between the tank, protective paper, & strap and begin eating away at the tank. Ohhh… I also sprayed the tank with bed liner (3 coats), in hopes of adding further protection. By the time I got the straps on tho, I had scuffed away -in a few spots, the gray coating that came on the new tank and my spraying coating. Thus, if u can get a second pair of hands for the entire process, I would recommend it! I then discovered that -assuming the bolts for the straps needed to face the same way(s) that I found them from the old tank & straps- that you must first install several of the bolts (upper strap to frame bolts), into their proper mounting holes on the straps BEFORE securing the straps to the tank (otherwise, u can’t get those bolts on). Once the straps are in place around the tank (while still on the ground), I too used a ratchet strap around the the strap & tank so that I could get the strap’s threaded rod thru the hole and get the nut around that rod. I used some thread locker too for good measure. After I got got both straps secured, I placed the nuts, washers on the threaded poles protruding from the bottom of the strap despite not yet having any kind of tank protection plate (figured the the nut would help to somewhat protect this threaded rod &, if needed, make it so I can get the nut off again in the future -repair the threads enough, should damage to threads occur over time. Regardless, if no fuel tank protection plate is used - I have yet to find one online- take steps to protect that threaded rod found on the bottom of both straps (in case of future use). I then lifted the tank in place, one strap at a time because I was by myself (extra set of hands would have been helpful at this point to. OHHH… an extra long wrench (check needed size on strap to frame nut prior to mounting tank… makes life easier while the tank is still on ground) I found I absolutely needed, in order to mount the tank, to use a long wrench (longer than the basic size) when securing the upper straps bolts to the frame. I ended up putting a piece of tape, for lack of a better known solution, on one end of my wrench in order to prevent the wrench from slippkng off the nut while tightening (again, it’s tight & dark when dealing with several of the tank strap bolts… assuming my choice to mirror the positioning & direction of the bolts as I found them when removing the OEM tank & straps was proper. In the end, I wish I would have better documented this process via a video, as I am sure many others have run into this. I have another tank to do at some point and will do so then. BUT if u r able & willing, u might consider taking a few pics or video for future use. Everything on this truck is a decent learning curve for me… it’s ALL new to me.
