Installing rear fenders on Hornet- big gap to fill

DavidC

OK, got the hardware, 3m strip calk, and I've made waterproof 1/4 in strips for the panel-frame gap at the bottom. So, I'm comfortable with the very top and the very bottom contact areas. What I'm unsure about is the large gap of varying size between the frame and the rear fender. The original material was deteriorated and cannot be used. My plan is to use rubber pipe insulation from Home Depot (lcosed cell foam rubber) to fill gap, sealed and held in place by some type of goop. What would you all recommend? High solids seam sealer?. Elastomeric caulk? Roofing cement? Other? I really have no idea what to use. Please help!

Hudsonly,

Dave C

RL Chilton

Dave-

I'm sure you will get varying degrees of opinions on this subject.  I don't recommend putting anything as far as a sealant at the bottom edge of the quarter.  If you look closely at the bottom of your rockers, you will notice there are weep holes located there to let out condensation.  If you put some kind of sealant down there, where does the water go?  Nowhere, to be exact, except stay there and start rusting.  

That said, it's good to have some varying degrees of sheet rubber on hand to cut small pieces so that you can "shim" the bottom edge of the quarter where needed to get it straight.  If you just bolt the quarter to the bottom of the frame, it won't be straight (and water has a tougher time getting out.  At the least, you should have a small stainless washer between quarter and frame.  At the most, you might have 1/4" gap here and there that you can stabilize with a small piece of rubber.  You've got to get your eye way down there and sight that leading edge to get it straight. 

DavidC

Sorry I was not clear. The bottom edge was originally shimmed with some type of oil impregnated fiber board, based on my best interpretation of what came out when I removed fender. I replaced this with a length of 0.26 in thick extruded vinyl trim from Lowes. About 3/4 inch wide, six drilled holes for the through-bolts.

The big gap I'm talking about is the space between trunk floor edge (top edge of frame rail) and rear fender panel. From what I removed at disassembly, this was made up of some type of gooped on sealant, foam rubber, and squares of some type of mesh material resembling a birds nest. Not done very neatly from the factory, IMHO. I can fill the largest gasp with closed cell foam rubber in the form of pipe insulation from a home center. But to get a good seal I need a caulk of some sort. Thinking of an elastomeric caulk, rubberized caulk, seam sealer, or other.

RL Chilton

I'm not putting anything back into that area.  I think it's just a moisture trap.  I've seen too many of the inside of the quarters that were rotting from the inside out.  

 In order to combat the panel ring, I'm gluing on some rubber sheet approx. 3" x 10" in a couple areas on the inside of the quarter.  Putting that rat's nest back in there is just asking for future problems, IMO.  Any of the big gaps at the bottom of the quarter should have been filled with pieces of rubber, as mentioned earlier.  

If you are intent on sealing it up, though, just don't use silicone (it eats the metal).  

Glowplug

Sorry I was not clear. The bottom edge was originally shimmed with some type of oil impregnated fiber board, based on my best interpretation of what came out when I removed fender. I replaced this with a length of 0.26 in thick extruded vinyl trim from Lowes. About 3/4 inch wide, six drilled holes for the through-bolts.

The big gap I'm talking about is the space between trunk floor edge (top edge of frame rail) and rear fender panel. From what I removed at disassembly, this was made up of some type of gooped on sealant, foam rubber, and squares of some type of mesh material resembling a birds nest. Not done very neatly from the factory, IMHO. I can fill the largest gasp with closed cell foam rubber in the form of pipe insulation from a home center. But to get a good seal I need a caulk of some sort. Thinking of an elastomeric caulk, rubberized caulk, seam sealer, or other.

The factory solution to seal  open areas that
were unseen and potentially noise makers was to place a material not unlike
what upholstery workers might call HORSE HAIR.  This material was stuffed
into the opening and a pressurized pail of what amounted to hot tar was sprayed
into the Horse Hair until it filled the gap.  A quick smear of the area
with a tar mop and the opening and the noise potential were overcome.   

As a previous poster indicates, the rust
problems that many Stepdowns incur were the result of traps for dust and that
coupled with moisture created areas that remained moist where corrosion
flourished. The primary factor that caused the rust in these areas was in
reality the lack of protection for the interior surfaces of the bare metal at
the back of the fender as well as the stamped metal that was the unit body
frame.  Most restorers are quite anal about treating bare metal and they
are creating anti-corrosion  barriers to
prevent failures due to corrosion.  Materials available now to treat and
protect these areas will assure a life longer that that of the restorer. Restoring
the crack with the Hudson
factory treatment is probably not advised, but if you devise a method where
your cracks fill allows for below and behind ventilation the fix should be
great.

The last car I did that had the quarters off I used sheet rubber about 1/4 inch
thick.  I cut this to overlap the opening at the trunk floor with the edge
at the fender cut to follow the fender contour.  I then used a gasket
makers hole punch to create a row of 5-6 holes that were aligned with the
opening.  Into the holes I stuck straws then using a tube of roofer's tar
I glued rubber filler to the floor of the trunk and the edge of the fender.
Also used a small dowel to smooth the edges of the joints and allowed it to
dry.  Once dry the straws were extracted.  This repair has been in
place for over 10 years and the seal has not cracked and the quarter shows no
signs of corrosion.  

 

DavidC

That's a beautiful technique, Old Farmer. Thank you all for your suggestions. No bare metal in there, BTW, all metal coated with undercoat, to include frame, wheelwell, and fender, so hopefully this will help. Won't overkill the process. Thanks again!

Dave