Trunk Floor Replacement (How to Replace Trunk Floor in a 1970 Dodge Challenger)

I’m writing this a few months after I actually did the work and couldn’t locate all the photos.  Plus when you are doing a project of this size its not easy to categorize everything into an item like “How to Replace the Trunk Floor in a 1970 Dodge Challenger”.  Because to get to the trunk floor, I had to take the tail panel out, plus had to replace part of the left frame rail.  Those will be included in another post.

The good thing is that all this new sheet metal is available.  I got the trunk floor and the tail panel from Sherman Associates Inc. (http://www.shermanparts.com/)  Just a few years ago (maybe not even 2) these parts weren’t available. You’d have to buy the trunk floor in two pieces and then weld it back together, rather than the one piece floor that I used just as the factory did.  Also, the tail panel wasn’t available at all.  You’d have to either fix your old rusty one, or try to find a good one from a junk yard (not easy, or cheap for a 40 year old Mopar).

 

This is how the back end of the 1970 Dodge Challenger looked after I removed the trim and bumper.    Rustier than I hoped.   The tail panel had quite a bit of rust around it because of moisture, etc. behind the trim.  I couldn’t leave it like this.  Well I guess I could, but I wouldn’t.   After the tail panel was removed, which wasn’t that bad with a spot weld remover and a standard 3/8” drill.  But also, I noticed that the rear cross-member directly under the tail panel was also very rusty.  Again, thankfully you can now order brand new sheet metal.

  

 

After removal of the Tail Panel, then I cut the trunk floor out.  Since there was no concern about re-using it, I only needed to be careful that I didn’t damage the frame rails or surrounding sheet metal.   And even though, I had already determined that the majority of the surrounding sheet metal pieces would be replaced, I decided to leave them in place until I got the trunk floor welded so that I would have a reference of where to put it.  Again, I used tools from Sears and Harbor Freight.  You can get some rather cheap air tools from Harbor Freight that work o.k.   It probably took me longer than most ‘body work’ professionals, but I’m new at this and I wanted to be extra careful to help not have any extra work.  Once it was removed, I determined that the damage to the left (drive side) frame rail meant that it would need to be replaced.  I bought a partial frame rail.  I’ll describe its replacement in another blog of the 1970 Dodge Challenger Restoration.

  

I next set the new trunk floor and tail-panel in there because I couldn’t stand it any longer and wanted to see what some new metal looked like in the challenger.  I think it looked good.  This is a little overly simplified because actually, I put these pieces in and out several times, test fitting before I was happy with everything.  But it did look good to have a new 1970 Dodge Tail-panel and trunk floor in the car for the first time in almost 40 years. 

It was during this time, that after talking to several people, and watching some car shows on TV (http://www.powerblocktv.com/site3/index.php/musclecar), and looking at all the rust on the car, I decided to have it media blasted in Lebanon TN, by “Blast from the Past” (http://www.manta.com/coms2/dnbcompany_gghw4r).  They did a good job and I had them also spray a coat of primer on it for protection.   They used crushed glass and the car looked much different when I got it back.  (I’ll post more latter).  Below is after I got it back, and replaced part of the left frame rail from year one (www.yearone.com), I put extra primer, and sprayed the insides of the frame rails with black paint (because you’ll never see them, or be able to get in there again) and the top of the rear shock-member that runs under the front of trunk. 

 

Next was a hard part, because we (my brother and I) had to take the nice, new, shiny, black, sheet metal and punch a bunch of holes in it so we could weld it together and put in the car.  First was punching holes in the trunk floor bracing from Goodmark Industries (http://www.goodmarkindustries.com/) (which is where a lot of the metal originated) so it could be welded to the underside of the trunk floor.  Then I welded them to the trunk floor and next carefully drilled lots of holes all in the new trunk floor (ugh!) so that I could replicate the spot welds from the factory to hold it to the frame rails.  Then I had to remove all the EDP coating around the spots where I would be welding else it would be difficult to impossible to get a good weld (by this point I had already welded in the new rear cross-member, again to be discussed latter).

Next, I primed the spots underneath that would be impossible to get to latter (because they would be attached to the frame rails) with 3M Weld-Thru Primer.  (good stuff, but expensive at $20-$25 for a spray can of it).  Then I welded the new trunk floor carefully into its final home, the back of my 1970 Dodge Challenger.  I think it looked pretty good.  I know it’ll all be covered up when I’m done, and I probably could have got some flat sheet metal and welded it down, but I thought this would be better. 

That’s pretty much it for this installment.  If you have any questions, email me or leave comments on my web site.  I hope to update this site more frequently than I have been, and get it up to date to where I am on the restoration of the Challenger, which isn’t as far along as I hoped to be at this point.  Its difficult to find time to work on it, and every time I take one part off to replace, the part underneath needs work or replacing too.  Its amazing how much rust can get in these vehicles.  But the good thing, there is lots of new sheet metal available, if you have the money and time to put it in.