Thomas' request for info on removing the GMC fiberglass rear cap so that
he can get an OE bath module inside reminds me of my experience three
years ago removing those large Phillips head screws that hold the cap in
place on my 76 Transmode. My goal was just to replace the screws since
they were quite rusted and unsightly.
I soon learned that removing the screws was an impossible task due to
the corrosion which had "welded" the screws to the metal inserts into
which they were threaded. The inserts had high-low threads on the
outside which were screwed into the fiberglass cap. No amount of
penetrating oil and power bar leveraging helped. Even my impact driver
would not break the rascal screws loose from the corroison's grip. I
was afraid of damaging the fiberglass with all the pounding and I
stopped that approach.
I was resigned to having to drill out each of the secrews but the screws
must have been hardened because I kept breaking bits. I was about give
up entirely when the last bit dulled and its spinning heated up the
screw. Was I supprised when I noticed the screw appeared to have
loosened. I quickly jammed a screw driver in the srew head, twisted,
and out came the screw and insert in one piece.
With this discovery, I quickly removed the rest of the screws and
insterts by holding an old Phillips screw driver against each screw head
and carefully heating the shaft with a propane torch. The heat
transferred to the screw and each insert loosened in the fiberglass and
screwed out.
This method worked for me, but anyone trying it should proceed carefully
so that the body is not overheated.
I replaced my screws with stainless steel Allen head cap screws (bolts)
after I drilled out the hole all the way through to the interior. I had
the inside completley stripped so I could install a nylon lock nut on
the threaded end. I epoxyed each nut on the inside to the cap so that
the bolts can be extracted without the nuts turning if I ever need to
take the cap off in the future. I believe that the high-low threaded
inserts are still available if one wanted to go back with the orignal
(but rusting) fastners.
Well this was a long story, but I hope it might help out someone who is
faced with the same problem I encounter a few years back.
Phil Stewart
he can get an OE bath module inside reminds me of my experience three
years ago removing those large Phillips head screws that hold the cap in
place on my 76 Transmode. My goal was just to replace the screws since
they were quite rusted and unsightly.
I soon learned that removing the screws was an impossible task due to
the corrosion which had "welded" the screws to the metal inserts into
which they were threaded. The inserts had high-low threads on the
outside which were screwed into the fiberglass cap. No amount of
penetrating oil and power bar leveraging helped. Even my impact driver
would not break the rascal screws loose from the corroison's grip. I
was afraid of damaging the fiberglass with all the pounding and I
stopped that approach.
I was resigned to having to drill out each of the secrews but the screws
must have been hardened because I kept breaking bits. I was about give
up entirely when the last bit dulled and its spinning heated up the
screw. Was I supprised when I noticed the screw appeared to have
loosened. I quickly jammed a screw driver in the srew head, twisted,
and out came the screw and insert in one piece.
With this discovery, I quickly removed the rest of the screws and
insterts by holding an old Phillips screw driver against each screw head
and carefully heating the shaft with a propane torch. The heat
transferred to the screw and each insert loosened in the fiberglass and
screwed out.
This method worked for me, but anyone trying it should proceed carefully
so that the body is not overheated.
I replaced my screws with stainless steel Allen head cap screws (bolts)
after I drilled out the hole all the way through to the interior. I had
the inside completley stripped so I could install a nylon lock nut on
the threaded end. I epoxyed each nut on the inside to the cap so that
the bolts can be extracted without the nuts turning if I ever need to
take the cap off in the future. I believe that the high-low threaded
inserts are still available if one wanted to go back with the orignal
(but rusting) fastners.
Well this was a long story, but I hope it might help out someone who is
faced with the same problem I encounter a few years back.
Phil Stewart
