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Copyright 2013 by
Randy Pflanzer
Technology Professionals Consortium
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   What's New?
 
  02/01/13 - Reformatted web page.

 

Rear Bumpers

The rear bumpers, boy, did I have trouble with these.  First, the instructions are not very helpful when it comes to placement.  Two, they don't really fit the frame mounts, or at least, mine didn't.

First thing was to get the proper placement and to make it the same place on both sides.  Since the bumpers stand out, if they are not located in the same location relative to one another, that fact will become readily apparent to anyone behind you.  So it was time to get out the laser level and some plumb bobs and go to work.  At this point, I have the body fit into it's final position on the frame INCLUDING the rubber body cushions, and the trunk support mounts in place and the truck screwed down to them.

I used a plumb bob to find the center of the trunk support mounts.  I wanted the holes for the bumper rods to be centered on the mount.  That placed the bumper midway between the taillights and the trunk openings.  This is slightly outside of the marks on the body for the bumpers, which the instructions tell you to ignore anyway.  On the prototype, the bumpers are closer to the trunk opening than the taillight.  The top line on the tape is the bottom of the trunk liner.  No holes can go above that line or your bumper mounts will intrude into the trunk and that won't look cool.

Vertical placement is pretty much a given since you have to be below the trunk floor.  Honestly, I think the bumpers look better up higher.  That's the way they are on a lot of the other kits out there, but there's no choice here unless you want to mess inside the trunk with different mounts, etc.  I drilled my holes as high as I could and then used my laser to point through the pilot hole to mark the location of the holes in the trunk support mount.  I used a drill bit extension to reach through the holes in the body to drill the holes in the mounts the bumper extensions.

The placement of the bumpers out away from the body is pretty much a personal choice.  I looked at a lot of pictures and found them everywhere from right up against the body to almost a foot away, which I thought looked a little funny.  The top of my extensions are about 1 1/4" away from the body and mounted so the inside edge is vertical when the car is level.

Unfortunately when I have the bumpers places vertically where I want them, the mounting holes are not level.  The mounting plate welded inside the rear bumper is not vertical, so the bumper extensions missed my mounting holes.  My solution was to cut a piece of angle to weld to the mounting plate that would match up to the bumper extensions.

Here is the angle tack welded in place.  You can see that the forward face is cut at an angle to match the angle of the extensions.  The extensions were shortened to match the new mounting location.  Now this took almost two days to get right.  I installed, clamped, measured, removed, cut, re-installed this assembly more than 6 times before I got it where I wanted and I got both sides the same.

I'm glad they are finally done.  I will finish weld these mounts once I break down the body and frame for paint.

Side Pipes

The first step in mounting the side pipes is to get an opening cut in the body in order to trial fit the pipes.  I used my laser level again.  I set it on the air filter and set a line down each edge of the pipes and onto the inside of the body.  Then using tape, I transferred those lines to the outside of the body.  This allowed me to get a very accurate location marked.  I cut just outside of the lines to give me a little clearance to mount the pipes.  I do not want to cut the final clearance in the body until the pipes are bolted into their final position.  Then I will cut in a 1/2" clearance all around.

I knew this was going to happen based upon posts from other builders.  The pipes do not follow the lines of the frame evenly.  In order to correct this, I had to grind on the mounting flange.

I would love to have a surface grinder to very accurately adjust these, but since I don't, I'll have to do the best I can.  The gasket should cover up the minor imperfections.

I used my metal ruler to look for gaps and high points and I ground the flange just about as far as I felt comfortable.  I ended up lower than this picture shows after three or four trial fittings.

After trying to get the right fit by grinding, I finally gave up and ordered some extra gasket sets.  I cut an aluminum spacer and tapered the gasket towards the cut edge.

I then sandwiched the spacer between two sets of gaskets.  This finally gave me the angle I was looking for.  I'm no sure how this will hold up over time, but I'm willing to give it a try for now.

I borrowed this mounting suggestion from another builder.  Rather than bolt the end tab of the side pipe directly to the frame mount, I used my torch and cut the frame mounts off of both sides.  I used some angle to make up a mounting flange that will get welded to the underside of the floor pan and frame.

The whole assembly looks like this and once mounted, I can weld in the angle to the frame.

This is the final fit I was able to achieve.  I think this will work out fine.  I have some guards to add to the muffler.  I will do that during the final installation after paint.

The next step is to mount the gas cap to the body and connect up the filler tube to the tank.  That work begins on the next page.