R50 Project: Chassis Refresh and Reassembly

Posted by L P on

It's been a while since our last update on the R50 project. A lot has been done in the past month, so it seemed like time for another post. We left off with the car mostly stripped, and the shell cleaned up and ready for work to begin. This car seemed to have been partially submerged in water at some point, so extra care was taken to flush every part of the under body / frame with clean water. Then it was completely dried using a leaf blower, compressed air, sunshine, and fans.


The R50 body right after being washed.


As a side effect of being submerged, or from living near the beach, most of the suspension and brakes had a lot of surface rust and went straight into the scrap bin. The body also had some surface rust above and around the rear subframe and fuel tank area, so that's where work began. Disclaimer: We are not a body shop and this is not a restoration! This is just a functional, budget-minded rebuild.


The area that needs attention. It's hard to see in the pics, but the rust is starting to form in some places.


Overall the car is very solid and clean underneath.


First, all the rust was removed using a wire wheel. Plenty of extra paint was cleaned off to be sure the metal was totally clean and there was no hidden rust. Most of the seam sealer in the area was removed as well, since there was rust starting along the seams. Sandblasting would've probably been better than the wire wheel, but with the car inside the shop, we didn't want to deal with the mess. After all the rust and seam sealer were cleaned off, the metal was treated with Ospho. Ospho is basically a liquid, phosphoric acid based rust inhibitor and metal treatment. It works great, just be careful not to get it on your skin or in your eyes!


Rust and seam sealer removed. Metal treated and ready for primer.


Next up, primer was sprayed over all the areas that were stripped. Then new seam sealer was applied in the same places as the factory did. This seam sealer is a little thicker than OEM and was spread on with a putty knife. The OEM stuff seems like it was thinner and brushed on. Again, we are not a body shop and this is not a restoration! Some $4 red spray paint from the hardware store was a decent match for Chili Red. Good enough for underneath the car anyway.


After primer.



Seam sealer applied.


 Back to red. Not bad for a $10 spray can job. Most of this is never seen once the car is assembled.


Meanwhile, work began on the subframes and suspension parts. The subframes and suspension parts on this car both had a lot of rust, so they weren't really worth restoring. We took some nicer stuff from our stock, but once thoroughly cleaned, even the nicest were starting to rust along the welds. So the same stripping, treating, and repainting process was done to the front and rear subframes, front knuckles, and front control arms. Then new OEM ball joints and Powerflex control arm, sway bar, and steering rack bushings were installed.


 Front subframe ready to go.


Rear subframe and front sway bar (OEM 24 mm).


Front knuckles with new ball joints.


Front control arms with new bushings and ball joints.


Front subframe assembled.


In the rear, the car got R56 trailing arms and control arms with an OEM 18 mm rear sway bar. Shocks/struts are OEM R56 Sport for right now, at least to get the car rolling. Suspension upgrades may come at a later point. The R56 trailing arms save 5.5 pounds per side of unsprung weight, and give some camber adjustment that this early R50 lacked. Plus they look better and won't rust. All 4 hubs are just used, low-mileage stock parts. New hubs are expensive.



Rear subframe and suspension installed.


Trailing arms, control arms, shocks/springs, sway bar, and hubs are all from R56.


Front subframe and suspension installed.


With everything installed, the car could finally go back on the ground! It had been disassembled for over 2 months, so it was cool to have it rolling again. Old axles were disassembled and the outer CV joints were installed and the nut to hub was torqued to spec. Otherwise, the front wheel bearings will have play and that's no good for rolling around. The car looks to be sitting extra high with so much weight out, and no bumpers. The stiffer R56 springs are probably contributing to that also. We'll have to see how it sits once everything else is back together. Now it's on to the fuel system, brake system, and engine / drivetrain. Stay tuned for the next update.


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