Pagoda Mercedes Front Fender Repair

This week I helped my friend repair the damaged fender on his 1971 280SL.  This is the same car on which I performed the side marker delete two months ago.  We noticed that there was a poorly done repair to the left front fender.  The significant gap between the fender and bumper along with improper body contour alerted us to a likely problem.

I started by sanding away all the filler.  Filler use was very extensive with coverage almost 1/4 inch thick in most places.  The pics below clearly show how thick it really was:

Pretty thick!  If you look at the top left corner you can see that the beltline was created almost entirely of bondo!  Quality work by the previous “craftsmen”.  Below all the bondo is removed and the extent of the damage and anemic attempt at metal straightening is revealed:

I started by tackling the bottom corner.  Here is a close-up of the damage:

There is a pretty deep crease that was left unrepaired.  Part of the reason that it was improperly metal worked is likely due to poor access as there is a headlight “bucket” inside the fender which houses the headlight assembly.  This makes it quite difficult to get a body hammer in there.  Once the filler was removed it also became evident that there was a huge gap in the lower corner between the headlight and the fender.  Here is the gap and the glob of filler that was used by the previous bodyman to compensate for the gap:

I had to cut the corner and push the metal around to correct the gap:

I then welded it up and finished the weld with some grinding:

Headlight back in place for test fit reveals corrected gap:

I then worked out the crease and recreated the lower contour:

I used a combination of techniques.  A stud welder is used to attached metal rods to the panel.  A special slide hammer puller is attached to these rods and the metal is pulled out.  I was also able to get a pick hammer in the back side and hammer on dolly.  Subtle contour recreation was done by adding metal with my mig welder and carefully grinding to sculpt the contour.  Some final finishing was done with a hand file.  Here is the stud welder in action – pictured on the top of the fender:

I next turned my attention to the top of the fender where the beltline detail was almost entirely obliterated in the front corner:

I used the stud welder here but was not very successful in pulling back the metal.  I think it was work hardened by the previous repair making it difficult to pull.  Its location near a corner and high crown above also contribute to its difficulty moving.  Again, access is very difficult from the back so working the metal from behind is nearly impossible.  Stud welder in action again:

I ended up having to recreate this beltline notch by adding metal:

Here it is after sculpting with grinder and hand file:

It looks pretty good but with careful inspection you can see that the area is still a bit low.  I’m going to have to figure out another puller set-up!  If you look carefully you can see that the horizontal crease in the middle of the fender was also eliminated.  I used hammer and dolly along with the stud welder.  The original deep crease caused the metal to stretch.  This leaves a bulge which cannot be worked out.  I had to use something called a shrinking disk to shrink out the bulge.  Sorry, no pics of the disk!  Below are some close-up pics of the crease worked out:

I will finish up the metal by planishing out all the tiny bumps with hammer/slapper and dolly.  That’s it for now!

Pagoda Mercedes Sidemarker Delete

This past weekend I helped a friend “delete” the sidemarkers on his 1971 280SL.  These markers were a safety mandate in the US but detract significantly from the lines of the car.  The euro models lack them for good reason.  Some people feel that this modification detracts from the originality of the vehicle.  I have mixed feelings about this.  I like the results but haven’t decided if I’d do it to my own vehicle.  My friend has done some other very significant modifications to this car including a Mercedes V8 engine swap.  The car drives amazingly well by the way!

Anyway, here is what we did.  Below you will see one of the rear quarter sidemarker deletes in progress.  Here the sidemarker was removed and a round patch was fashioned and tacked in place.

Next, the tacks were ground flush on both sides and planished.  Planishing is a process where the metal is worked with hammer on dolly, for example, to smooth out the surface.  In this case, the planishing was done to stretch the weld area in order to undo the shrinking that occurs by welding.  As I’ve mentioned in other posts, shrinking around the weld causes the surrounding metal to get pulled in, resulting in distortion.  Planishing the weld “magically” removes all the surrounding panel distortion!  Below the tacks are ground and planished:

Next, I welded between the tacks and closed up the sidemarker mounting holes on either side.

Again, the weld bead is ground flush on either side and planished to get a flawless result!

The same was done on the other side and on the front two sides.  Here is the front:

This whole process took two full days.  Planishing the welds probably took most of the time but it was worth it!

Mercedes 240D Inner Door Frame Cover R/R

The W123 chassis Mercedes diesels are truly amazing cars but they, like all cars, do have some faults.  The door frames have an inner plastic cover which is color coded to the interior.  With time these covers shrink and crawl up the frame leaving large unsightly flowing wrinkles.  Mercedes seems to have most parts available but this is not one of them!  As a result, most w123 owners simply remove them or just deal with the eyesore.

I was lucky enough to find one of these NLA covers at the Mercedes Benz Classic Center.  It was available in blue for only the driver’s side door which happens to be the door I’m currently working on – previous couple of posts.

Here is the new cover:

New interior door frame cover.

 

Here it is next to the old one:

old and new back end

 

old and new front end

 

This is the first such installation for me.  I learned that you have to start installing on the back top corner in order to avoid tearing the paper thin edge which folds over the edge of the frame.

Here it is installed:

Cover installed

 

cover installed

That’s it for now.  Cold weather here in the Northeast is probably going to slow down my progress!

 

 

 

 

Mercedes 240D door repair. Welding in patch panel.

The weather cleared and I got started on welding in the patch.  I sourced it from a pick ‘n pull yard in Maryland.  I showed up with a cordless sawzall and went to town on the poor Mercedes.  Sadly, the car was rust free. It must have had a blown motor or something.  Why can’t people fix these cars?  In many other parts of the world, cars are not considered disposable so they keep getting repaired.  I understand that a rust bucket deserves the crusher but a rust free survivor deserves the dignity of some mechanical repairs!  Anyway, here are some pics of the door corner that I cut out of the poor old mercedes:

Rust free patch panel juxtaposed to rusty part from my car

Inner aspect of patch.

 

In the above pics, you can see that I trimmed the patch to fit into my car.  That is, the piece I cut in the junkyard was slightly larger than what is pictured.

After cleaning the paint away from the patch and the car door where welding will take place, I tack welded the patch in place.  It took a couple of tries to get it perfectly aligned.  This is critical because sloppy work here will create inconsistent panel gaps.

Tacked in place. Outer view.

 

 

Tacked in place. Inner view.

Again,  tacks are placed every 3/4 inch or so apart and then welding between the tacks is performed.  Jumping from one point to another is crucial here so as not to create too much localized heat – thus panel distortion.  This is especially important when welding on large flat-ish sheets of metal such as door skins or quarter panels.

Next, everything was welded up.  Welds were ground flush with the surrounding area using an angle grinder for readily accessible locations and a dremel for tighter quarters. 

 

Welded up and metal finished. Outer view.

 

Welded and metal finished. Inner view.

Inner view. Closeup.

Door repair complete!  Now I will protect the inner aspect of the door around the weld with POR-15 and get the panel painted.

 

Mercedes 240D Driver’s Door Repair. Rust Cut Out.

So on to my next project – the unsightly rust on the driver’s door.  This occurs from water entering the door by leaking past deteriorated rubber window scrapers.  If the drain holes on the door bottoms are blocked the water and salt have a hayday with the sheetmetal.  I’ve been tackling this repair over the past several days.

Rusty door:

These pics demonstrate very typical rust on the W123 chassis Mercedes.  This can be present on cars driven on salt free roads as well.  In my case it was serious as this car is driven mostly in the northeaset USA.

My favorite way of precisely cutting out rust is by using a thin cut-off wheel mounted on a Dremel tool.  I use a sharpie to mark the cut.  A larger cut-off wheel on an angle grinder is best left for longer, straighter cuts and a plasma torch leaves ragged sloppy edges and I don’t own one anyway!  You can make precise, controlled and quick cuts using this technique.  Having trained as a surgeon, I take pride in performing these tasks in a methodical and precise manner.  I know it’s only a car but while  in my hands,  it is my patient!

Here is my door sans rust:

I don’t necessarily use straight lines when cutting out sections as I like to retain as much original sheetmetal as possible.  I know that this is not a high value car but for me  it’s a matter of principle!

Here is my “workshop” for now.  Pretty pathetic, I know.  I’d do it in the garage but that spot is currently taken up by the currently inop Adenauer (1958 300d) visible in the pic.  Also notice the original edition (1949) Hazet Assistent tool trolley. These were used in the service departments of  many German car dealerships at the time.  Having it beside me somehow makes my work feel more official! 

That’s it for now – my work is interrupted by Hurricaine Sandy.  Hopefully a tree won’t destroy all my work.

Mercedes 240D hood rust repair

Well, this is my first post!  Basically, I’m going to document a rust repair that I performed on my car this past month.  No frills, no nonsense, documentation.  Well maybe some nonsense!

So this is the car.  It’s a daily driver that I bought about 3.5 yrs ago. It takes me everywhere reliably and cheaply.  Being a Northeast car it has its share of rust but overall not too bad.  About 90% original paint.

Not too shabby right?

Well, look further at this nasty hood rust.  Yikes.

This all gets cut out and spot welds drilled out with a spot weld cutter-basically a tiny hole saw with some bells and whistles.

Rust cut out.

Notice that the inner support is fairly rusty – basically heavy surface rust and pitting.  This gets de-rusted with several days application of naval jelly.  Every bit of rust is dissolved and then the support is painted with a weld-thru primer which is necessary since the new piece will be plug welded onto the support.  Weld -thru primer somehow resists the heat!

Inner support de-rusted and weld-thru primed

Here you see the old piece juxtaposed to the new piece I fabricated from 20 gauge cold rolled steel.  Notice that the patch has holes pre-drilled for the plug welds.  Plug welds basically are a quick and effective way to duplicate a spot weld.  After some dressing of the weld and some more fancy work they can be made to look exactly like the original spot welds.

old piece next to new patch

Next the patch is tack welded in place.  I jump around with the tacks so as not to put too much heat in one place at a time.  Heat causes metal shrinkage which pulls all the surrounding metal into the heated area thus causing panel distortion.  As the hood has original paint, I would like to retain as much of the originality as possible.  Metalworking the top surface of the hood to compensate  for distortion will necessitate a hood repaint.  I don’t want to do that.  Most people would not have even bothered to repair this rust.  A new hood would have been their solution.  Being an impractical purist, I decided that it would be nice to keep as many original panels as possible!  Also, notice that I’ve started welding in the plug welds.

patch tack welded in place

The gaps between the tacks are welded up next.  Again, jumping around to prevent too much heat.  I use a heat absorbing gel around the work area to absorb some of the heat and minimize distortion.

All welded up.

The weld bead is ground down flush using an angle grinder and finished off with a hand file. Final finishing by hand with a file offers more control and makes me feel like a real craftsman!

Weld bead ground flush.

Below you will see a close-up of a duplicated “spot” weld.  These plug welds were ground flush, circumscribed with a punch and slightly ground within the circle using a dremel to create a subtle depression exactly simulating a spot weld.  All “spot” welds were placed in the exact spot as from the factory.

spot weld duplication

The repair is complete and ready for paint.  The back side of the weld will also be painted!