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Topline Truck Bed Extender Installation - 2008 Toyota Tundra

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How to Install the Topline Truck Bed Extender on a 2008 Toyota Tundra

Today on our 2008 Toyota Tundra, we're going to review an install, the Top Line Bed Extender, part number BX4004-01. Here's what our bed extender look like once installed. What's really nice about the bed extender, especially on these short bed pickups is that it adds approximately 2 feet extension onto our pickup bed. Additionally, when it's not in use, it can simply be folded up as the clamps will secure the sides to the main body and then it folds down where the clamps will hold it to the brace. We can simply just close our tailgate and it's stored inside the pickup bed, or we have a situation where we need the entire length of our tailgate without the bed extender, we can pull the pin, which has a nice detent on it to keep it in place. We pull it out of the bracket on both sides and we completely remove our bed extender, opening our tailgate back up. Now, let's go ahead and show you how to install it. Now, to begin our install, we're going to open the tailgate.

We'll go ahead and bring in the tailgate extender and find our mounting location. Now this is the Top Line Universal Bed Extender, which means it has an adjustment point. That's going to be here in the center. We can adjust out the length or width to match the tailgate attachment points. When adjusting it, we want to make sure we do it equally on both sides of the center adjustment point, so from the support brace to the clamp on each side being equal. When looking for the mounting location, we need a level surface for all three attachment points for the lower bracket.

If I swing the tailgate extender up while holding the bracket flat to the tailgate, we have the rear attachment point here under the pivot point. Then, I center and forward attachment points. Let's go ahead and get both sides set. Once you have the width set, we'll go ahead and tighten down the clamp to help hold it in place. Keep in mind that each process we do here on the driver's side, we're going to repeat identically on the passenger side. Next, we're going to hold the bracket tight to the tailgate as we raise up the extender.

Double check your alignment mark. Make sure you're in good location and then use your paint marker to mark the center and forward attachment points. Then, we can go ahead and move the extender from the tailgate. We're going to go ahead and remove the bracket from the bed extender. We'll pull the pin and just slide it off. We can then take it back to the tailgate, line up the marked attachment points, so we can mark our third attachment point.

We'll line it up with the premarked attachment points and also use our reference mark, and then our paint marker to mark out that third attachment point. Now, we're ready to drill out our hole. To start the drilling, we'll center punch each hole first. Now to drill it out, we're going to use a step-bit process starting with a smaller pilot bit and then opening up to our final size. Now with our holes drilled out, let's go over our hardware. We're going to have a bolt that'll go down through the bracket through a gasket and then into the nut that gets inserted into the tailgate. The nut will go through our predrilled hole, get turned and tightened down, locking it in place. Let's go ahead and put the nuts in position through our predrilled holes. Now, as I put it down into place, I'm just going to take my bolt and turn it so that it will accept the bolt as it goes down into position, making it easier to tighten down once we get our tailgate extender bracket back in place. Now, once we have all 3 of the nuts into the tailgate, provided with the install kit is a gasket or rubber isolator that'll sit between the tailgate and the bracket. We can then go ahead and take our hardware and put it down through the bracket. Provided with our install kit is a 5/32 Allen wrench, which we can use to tighten down the hardware. I'm just going to go ahead and get everything started. Keep in mind as I'm tightening the hardware, I'm not going a full 100%. I want it to still be a little bit loose so we can set the extender back in and make sure everything lines up before we fully tighten it down. With our brackets in place, we'll go ahead and put the tailgate extender back into position, put the pin back in and make sure everything is lined up and works properly, open it up, swing the side out, locks in nicely. I'm going to go ahead and tighten down the center fastener to hold it in place. Once I've got that tight, I can go ahead and rotate the side out of the way, tighten down the forward fastener, and then I'll pull the pin, pick it up out of the way and tighten down the rear fastener. Now, just like that, our bed extender is in place and we're ready to hit the road. That'll will do it for the review and install of the Top Line Fold Down Truck Bed Extender, part number BX4004-01, on our 2008 Toyota Tundra.

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Info for these parts were:

Video by:
Joshua S
Test Fit:
Nicholas E
Video Edited:
Jacob T
Video Edited:
Chris R
Video Edited:
Mike H

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