Orson_Yancey
NAXJA Forum User
- Location
- Portsmouth, NH
I would like to describe my improvement of using stainless steel screws in all of the
front grille and headlight area. I recently had to take a part the headlight bezels,
molding and front grille while I was working on new sealed beam headlights to pass inspection.
Here is what I encountered. While taking a part the headlight molding and bezels, I found
that most of the M4 metric sheet metal screws tapped their way into the fiber glass front panel.
Over the years, the road salt had eaten away the steel of the metric sheet metal screws,
right under the head of the screw, the part of the screw that was not turned in to the fiber glass.
Several of the plain steel metric screw heads twisted right off immediately, leaving a rusty
stub still in the fiber glass front panel.
So, I found myself having to remove the remaining stubs from the fiber glass front panel.
I did this by drilling two small holes (one on each side) of the remaining stub down,
1/4" to 3/8" into
the fiber glass removing fiber glass from around the outer part of the stub.
Next, I used a small punch and tapped with a hammer until the stub moved back and forth.
Then I used either a needle nose pliers or a regular pliers to turn counter clockwise and
remove the remaining stub.
At this point, I had removed the remainng stub, but the screw holes were enlarged somewhat
at the outer part. It would have not been practical to go to a larger diameter screw.
I filled the holes with Permatex liquid metal filler and let is set for a few days.
Loctite also makes a liquid steel product. These products are all plastic like and similer
to epoxy. I suppose epoxy would also work fine, but I felt the liquid metal filler
would be easier to apply to a sideways surface and to drill later. Afterall,
I did not need a filler that is much harder than the original fiber glass.
After the liquid metal filler set, I drilled small holes for the new screws.
The original OEM screws were plain steel Metric M4 x 20 mm sheet metal screws.
in the places that tapped into the fiber glass front panel and plain steel #8 x 1/2"
that held on the headlight bexels.
For less that $10.00, I purchased 24 stainless steel sheet metal screws, #8 x 1/2", 3/4"
and 1" lengths. I put in 1/4" longer screws in the holes that I had to enlarge
and then fill-in with liquid metal filler.
Anyways I put in stainless steel screws in all places.
Another poor design of the OEM metric sheet metal screws was that the thread of the
screw was deep while the minor diameter, i.e. the shaft of the screw was too small.
This left too little metal remaining after some years of rust and explains why the
metric sheet metal screws twisted-off so easily. It see that #8 SAE sheet metal screws,
although they had approximately the same outer diameter as the M4 sheet metal screws,
the thread was slightly shallower, leaving more metal for a larger minor diameter, i.e.
the shaft portion of the screw. (The longer the screw, the less thread depth is needed,
but a larger minor diameter shaft is needed.)
The only OEM screws that were stainless is the two #8 x 1.25" sheet metal screws that
hold on the amber side marker lamp bezel. Over the years, they did not rust at all.
It is too bad that AMC/Jeep did not use
more stainless steel screws, due to cost cutting reasons - for my 1988 XJ.
I also put in 8 stainless steel screws that hold the front center grille.
A few weeks earlier, I changed the windsheld and had to removed the windshield wiper
arms. At that time, I also removed the plastic panel below the windshield wiper shafts and just
in front of the windshield. I used 8 stainless screws when I put the plastic panel
back on. So, over time as I have been removing and putting back various exterior
panels, I have been putting in stainless steel screws. I even used stainless steel
screws to fasten the front license plate, to eliminate rust spots from discoloring the
license plate. The additional cost of using stainless steel screws over zinc is small
but the benefits are no more screws rusting off, no discoloring of nearby panels, and
the vehicle looks nicer.
I find that in the North Country, the road salt rusts the front of the vehicle quickly.
I mention this project to provide ideas to others and to see if other people have encountered
the same problem with screws rusting just below the head and then easily twisting-off.
front grille and headlight area. I recently had to take a part the headlight bezels,
molding and front grille while I was working on new sealed beam headlights to pass inspection.
Here is what I encountered. While taking a part the headlight molding and bezels, I found
that most of the M4 metric sheet metal screws tapped their way into the fiber glass front panel.
Over the years, the road salt had eaten away the steel of the metric sheet metal screws,
right under the head of the screw, the part of the screw that was not turned in to the fiber glass.
Several of the plain steel metric screw heads twisted right off immediately, leaving a rusty
stub still in the fiber glass front panel.
So, I found myself having to remove the remaining stubs from the fiber glass front panel.
I did this by drilling two small holes (one on each side) of the remaining stub down,
1/4" to 3/8" into
the fiber glass removing fiber glass from around the outer part of the stub.
Next, I used a small punch and tapped with a hammer until the stub moved back and forth.
Then I used either a needle nose pliers or a regular pliers to turn counter clockwise and
remove the remaining stub.
At this point, I had removed the remainng stub, but the screw holes were enlarged somewhat
at the outer part. It would have not been practical to go to a larger diameter screw.
I filled the holes with Permatex liquid metal filler and let is set for a few days.
Loctite also makes a liquid steel product. These products are all plastic like and similer
to epoxy. I suppose epoxy would also work fine, but I felt the liquid metal filler
would be easier to apply to a sideways surface and to drill later. Afterall,
I did not need a filler that is much harder than the original fiber glass.
After the liquid metal filler set, I drilled small holes for the new screws.
The original OEM screws were plain steel Metric M4 x 20 mm sheet metal screws.
in the places that tapped into the fiber glass front panel and plain steel #8 x 1/2"
that held on the headlight bexels.
For less that $10.00, I purchased 24 stainless steel sheet metal screws, #8 x 1/2", 3/4"
and 1" lengths. I put in 1/4" longer screws in the holes that I had to enlarge
and then fill-in with liquid metal filler.
Anyways I put in stainless steel screws in all places.
Another poor design of the OEM metric sheet metal screws was that the thread of the
screw was deep while the minor diameter, i.e. the shaft of the screw was too small.
This left too little metal remaining after some years of rust and explains why the
metric sheet metal screws twisted-off so easily. It see that #8 SAE sheet metal screws,
although they had approximately the same outer diameter as the M4 sheet metal screws,
the thread was slightly shallower, leaving more metal for a larger minor diameter, i.e.
the shaft portion of the screw. (The longer the screw, the less thread depth is needed,
but a larger minor diameter shaft is needed.)
The only OEM screws that were stainless is the two #8 x 1.25" sheet metal screws that
hold on the amber side marker lamp bezel. Over the years, they did not rust at all.
It is too bad that AMC/Jeep did not use
more stainless steel screws, due to cost cutting reasons - for my 1988 XJ.
I also put in 8 stainless steel screws that hold the front center grille.
A few weeks earlier, I changed the windsheld and had to removed the windshield wiper
arms. At that time, I also removed the plastic panel below the windshield wiper shafts and just
in front of the windshield. I used 8 stainless screws when I put the plastic panel
back on. So, over time as I have been removing and putting back various exterior
panels, I have been putting in stainless steel screws. I even used stainless steel
screws to fasten the front license plate, to eliminate rust spots from discoloring the
license plate. The additional cost of using stainless steel screws over zinc is small
but the benefits are no more screws rusting off, no discoloring of nearby panels, and
the vehicle looks nicer.
I find that in the North Country, the road salt rusts the front of the vehicle quickly.
I mention this project to provide ideas to others and to see if other people have encountered
the same problem with screws rusting just below the head and then easily twisting-off.
