Rock and Roll...

I learned that the Crossfire coupe, which uses the Mercedes SLK base, has a few vestigial provisions built into the unibody.  Of interest for this project is the fact that the bulkhead that separates the passengers from the hatch area has all the provisions for roll bars, even though the coupe is not equipped from the factory with them.  I found these instructions for replacing the roll bars in a Mercedes SLK - and the parts (even the unibody parts) are identical in the Crossfire, so I decided to investigate further.

Upon removing the plastic cover on the top of the bulkhead and moving the carpeting out of the way, I was able to confirm that indeed there were openings for the bars and holes for the bolts.  All one really has to do is get a set of roll bars and install them.  Well, more or less...

You see, there are a few things that need to be done first, and all of them are a bit of a pain.  First, the roll bars.  They can be a little expensive.  But I decided if I could get a pair for less than $100 I would go ahead with the modification.  eBay obliged me and soon I had two roll bars.

I found that the bars are quite long and cannot be installed in the coupe without either cutting a hole in the roof or cutting the ends of the roll bars off.  I didn't want to lose the strength so I pondered the possibilities and came up with an idea that would allow me to remove the ends, and reassemble them in the car, preserving most, if not all of the strength of the bars.

I cut the bars below the upper mounting points.  This required a trip to a local machine shop.  They took care of it in short order and soon I had two roll bars and four roll bar ends.  Next I went to the pipe section and purchased a 24" length of pipe the same outer diameter as the roll bar internal diameter.  I had the pipe cut in 5" and 6" lengths (2 of each) to use as inserts.

I purchased 10 bolts - 8M-1.25 x 25 - the size necessary to bolt the bars into the car - along with lock washers to fit.  I also purchased a tube of JB Weld to use to epoxy the tube inserts inside the lower roll bar parts.  I glued the inserts into the pieces of the roll bar that I had cut off, and set them aside to dry overnight.

Once home, I removed the necessary parts to gain access to the mounting points for the roll bars.  I installed the roll bars and tightened them down.  Then using a triangle-square I marked the location of the roll bars and depth from the back of the bulkhead to the back of the roll bars.  Then I removed the roll bars and installed the bulkhead cover.  With the cover installed, I transferred the roll bar locations to the cover with blue masking tape.  Each bar is 1 3/4" in diameter, so I was able to calculate the four squares that the bars occupied.

I removed the bulkhead cover and drew "X"'s on each 1 3/4" square to locate each center.  Using a center punch, I marked each center.  Then I drilled each center to create a pilot hole.  With a 2" hole saw I drilled out the four holes.  I got lucky and managed to place them perfectly for the roll bars to go through to the mounting locations.

I put the bulkhead cover back in place and installed the lower and upper roll bar parts and bolted them in place.  Next I took the rubber grommets that had come with the roll bars and glued them into place with heavy duty weatherstripping cement.

I relocated my fire extinguisher and radar detector remote speaker, then reassembled all the parts I had removed in order to access the mounting locations.

 

The major time for this job was spent getting the supplies, having the bars cut down, and making careful measures before cutting the bulkhead cover.  Other than those things, this job went very quickly.