Likely spot for rust to start

[jeffc280sl]

I've been busy replacing driver side firewall, floor pan and side rail.  As I reassembled the car I noticed what I believe is a likely place for a failure in the weather tight seal between the firewall, side rail and inner front fender panel.  The inner fender panel requires a rubber gasket which seals the fender area from moisture.  It is very important that this gasket be checked and renewed if there is any question about its integrity.  Most obvious is a gasket failure which leads to moisture invading the fender followed by rust.  Less obvious is the need for this gasket to seal the joint where the inner fender panel, firewall and side rail intersect.  The gasket must be cut long enough to cover a small traingular shaped opening at this intersection.  The rubber gasket must fit tightly against the fender and at the bottom it must fit tightly against the outside rail cover.  If not, moisture will find its way behind the firewall and then downward inside the rail.  This seal failure is one important area to check on a regular basis to prevent having to do the kind rust repairs I faced.

Jeff C.
1970 280SL 4-speed

[bjudd]

Jeff

Are you taking any pictures of the work you're doing?   I'd love to see what it looks like.



bjudd
1969 280 SL 5 sp

[Ben]

Yeah me too !!

Another area for me to check !!

Regards,
Ben in Ireland.
'64 230SL 4sp.

[jeffc280sl]

As mentioned the inner fender panel seal is an important area to maintain.  Where it meets the fender is pretty easy to spot problems.   I'll try to describe the lower section in more detail.

The firewall panel is flat in one direction and curved in the other.  The outside edge is straight and vertical.  The front lip of the rail is angled to meet the firewall and it is welded to it to form a seam.  The inside edge of the rail is welded to the firewall on the interior of the car near the floor pan.   The bottom and side exterior edge of the rail are welded to the firewall on the exterior of the car.  

There is a small gap where the exterior vertical side of the rail meets the firewall. This gap exposes the interior and exterior section (inside the fender) of the rail to weather. It is protected from the elements by the rubber gasket of the inner fender panel.  In this area the gasket seal must be compressed against the outer fender and further down compressed by the seam where the inner fender panel and outer rail cover meet.  

If this gap is exposed to the elements by a poor seal, the interior of the rail and firewall will take on moisture.  If unattended the firewall/rail seam will rust. Eventually the entire lower rail will be exposed to the elements and rust.  The lower section of tire jack holes/brackets will rust. The interior section of the floor pan will be exposed to the elements from rust in the firewall and the interior of the rail.  It just gets worse from there.  The rubber gaskets are cheap and easy to install.  I suggest everyone consider replacing them.

If I were buying a W113 and had the opportunity I would remove the inner fender panel and carefully inspect this area.

Jeff C.
1970 280SL 4-speed

[J. Huber]

Hi Jeff. Now that you are well-versed in these rust areas, want to do my car? Sadly, it is way too late for rubber gaskets on mine. I urge anyone who still exposes their cars to the elements to take Jeff's advice seriously...

James
63 230SL

[jeffc280sl]

Hi James,

If you were closer I would like to help you out in person some way.  Maybe I can still be of benefit long range as you move forward taking care of your "challenges".  Please let me know if you have any questions.

Jeff C.
1970 280SL 4-speed

[J. Huber]

Thanks Jeff. At a minimum, do share some photos of the project here if you can.

James
63 230SL

[jeffc280sl]

Can't seem to post pics on this site.  Send me your email address and I'll share them with you.

[Chad]

If I may throw in my non-tax-deductible two cents...

This forum is a fantastic resource for enthusiasts of these cars, and there are many technical threads and help that is very useful, however very little use of pictures, diagrams, etc. is used.  Digital cameras are probably pretty common among the forum members, but perhaps not. Anyway, visual objects, pictures would add greatly to many  technical or restoration related threads/posts and they are virtually never used on this site.  Is it a problem with user-friendliness of the site for allowing members to post pics???  Can something be changed to change this and help members post pics easier within their threads??  Is it a memory problem?? Shopforum is an excellent of a forum for mercedes cars that has this problem worked out somehow, I believe.

Anyway, my two cents of constructive criticism.



-CD-
1967 230SL, 113.042 10