Front nose and grill metalwork
The 190SL is one of the earliest cars to be built in the "monocoque" or "unit body" design. With the exception of the rocker panels the steel body panels, frame and floor parts are all welded together to form a very strong single unit. The doors, hood/bonnet, trunk or deck lid are aluminium together with the 'A' and 'B' frames and dash. The aluminium parts will generally not need to be replaced but all of the outer body panels are made of steel and may need to be repaired or replaced. I was fortunate that with the exception of one or two minor areas there was virtually no rust on the body panels. Majority of the work on the left front wing and nose piece was panel beating badly repaired panels filled previously with bondo/polyester filler.
The factory fenders/wings and the nose (or tail) panels (item 45) were assembled and welded together on factory jigs, thereby insuring good fit and alignment. The entire front or rear could be ordered from the factory as one unit. Nowadays one has to resort to separate wings and nose/rear panels.
The nose panel, tail panel and fenders were in perfect rust free condition and only required a small attention with the hammer and dolly to work out small dents and ripples. Previous repairs were done with polyester filler rather than metal work. This was finished off with a small amount of lead to perfect.
If replacing the nose panel before welding ensure that the bumper brackets line up and that the holes through the nose have equal vertical and horizontal distances. The bonnet should be correctly aligned with the top of the nose. As one would not have access to the factory body jigs ensure that the headlamps are facing in a straight line. Note that the headlamp buckets are a separate part and not an integral part of the frnders or nose panel. This is an area overlooked and results in misalignment of headlamps. Another point to consider if replacing the nose panel is to ensure that the joint between the two parts is not overlaped with the fenders. Corrosion will result in latter years as the front tyres will throw up debris and become trapped between the two layers of metal overlaped. A butt welding this jointis typical of repairs at a restoration shop as opposed to overlapping as commonly done by bodyshops.
The grill area of the nose before restoration looked perfect until I trial fitted the chrome grill. The chrome barrel with the two spacers was impossible to slide into the nose aperture. The problem was either that the grill was too large or that the nose had panel damage not repaired earlier. Once stripping the paint and bondo it was the latter of the two. Incidentally no two bonnets or grills will fit different cars as these like the rest or the 190SL were hand built and made to fit by the factory workers. Taking measurements from different 190SL's it was obvious that the vertical distance was one centimetre too small in the middle where the chrome star would sit. The grill will fit with force when removing the chrome spacers. On the point of originality and as the spacers were probably there to prevent contact corrosion of the barrel with he upper and lower wings I decided to fix the problem. Most 190SL's I have viewed have one spacer, but there should be two, one upper and one on the lower. The bonnet line was higher than the top of the nose indicating that the top panel need to go up. A mini ‘Ram’ with a Portapower was used to correct the gap with a perfectly fitting grill.
With a perfect grill fit, it was time to lead around the upper nose section to fill holes previously made by a screw type body puller and to tighten the gap between upper chrome grill and nose panel lip.
The grill wing ends should ideally have a 1mm gap. Load loading and panel beating achieved this although at present there is greater than 1mm to allow for the thickness of the paint. 
