Passenger frame rail and radiator support repair

The Passenger frame rail was in much better shape than that drivers side, If you recall I completely replaced the drivers side frame rail. This side only required a new section part to just replace the really bad area. The front most part of the frame has damage from battery acid dripping on it, and from someone drilling holes to access the bumper brace bolts.

_MG_9638I started by removing the shock tower.  The passenger shock tower was not quite as bad as the drivers side, but it has partially rusted through at the bottom.  You see from the picture on the right I left part of it in place to provide some rigidity to the top lip where the fender attaches.

_MG_9641Next I removed the suspension mounts from the frame.  I was surprised it only took a few quick runs with the air chisel to break the welds loose, that and the fact that there were only 14 spot welds holding the suspension to the frame.  I did not remove all the suspension brackets nor the swaybar mount.  I only removed what I needed to  allow me to cut the old section out, or any parts that would be left on the original frame.  Since I’m replacing the suspension I’ll be using all new brackets.

Once I was ready I measured the length of the new replacement rail, and marked the old frame rail leaving about 2″ overlap that I would use for adjusting the fit and placement.  With the Plasma cutter warmed up, I zipped the old front end off the car.

If you look closely at the picture of the front end sitting on the floor, You’ll see some primer on the top of the radiator brace.  This is a spot where the car had been repaired a long time ago.  I think at some point the car was in a minor fender bender, and it bent or broke the radiator brace.  Someone had taken another part and braised the section on.  It was a pretty decent job, but the seam was right on top where it was clearly visible, so I decided to replace the radiator brace too, I mean it was off the car already. 😉

With the front end out of the way, I finished grinding the spot welds down, and removing the few bits from the driver side inner fender.  I also noticed some rust in the very front of the inner fender.  In the images below, I made a small replacement section.  This one I made by measurement and eye, not the cardboard template you have seen me use in other posts.

The next step was to start getting the new frame section ready to install.  I mocked up the frame rail and measured it against the Driver side.  I cut one section of the frame to my measurements, This allowed me to clamp the new frame section in place and double check my measurements.  I used a section of angle iron to act as a straight edge and to brace the frame rail.

This next part turned out to be the most frustrating part of this whole job.  Using the frame alignment jig, I checked that that the mock up was the correct length and it was square with the rest of the car.  When I ran my tape between the frame rails it was 27 1/2 inches along the full length, so I knew the two frame rails were parallel.  And if I used the frame alignment jig with the suspension mounting holes on both the Driver and Passenger side, they lined up exactly.  So again I knew I had the right length.  the problem came in when I tried to measure if the frame was square with the car.  Using the frame alignment jig I would measure from the floor pan seat brace holes to the front of the frame in the alignment holes there.  This measurement was showing that the frame was off by almost 1/4 of an inch!.  After several hours of measurement and double checking, I finally figured out that the new floor pan seat brace on the drivers side has its alignment hole off by 1/4 of an inch.  I did not notice it when I was installing, since I was pulling measurements from the seat pan itself, and not the floor brace.

With that out of the way it’s time to mock up the front end and start to assemble the frame rail.

The pictures above cover the steps.  First I drilled some holes to allow me to plug weld a plate inside the frame rail to help strengthen the joint.  I used some scrap sections from a spare floor brace I bought for the drivers side, since it was the same gauge as the front frame rails. I forgot to take some pictures of the welds before I ground them down, and primed them, but you can see that it’s hard to find from the outside, and has a good strong seam with a backing plate.  When I mocked up the radiator brace and measured it, I was off by between 1/16 and 1/8 of an inch, well inside the 3/16 tolerance.  With the inner frame rail looking square and good, I did the same work to the outer section.

Here you can see the plate next to the frame rail after I sprayed them with weld through primer.  In the last few shots you can see it welded in place, and the the welds ground down smooth.

_MG_9811The last step was to paint the inside of the frame rails with a sealer paint that’s designed to coat the inside of the frame, and run between the cracks and nooks.  For this I’m using Eastwoods Internal Frame coating, it goes on easy and dries to a very hard surface.  It comes with a 2 foot long hose and spray nozzle, so you can reach way down inside.  I used some the the suspension holes to get areas beyond the reach of the hose from the front.  This is much easier to do now that I have the front off, than later, I could still do it, but this way I look in and see that I got everything.

Next time I’ll assemble the radiator brace, and the passenger inner fender.