Bill,
I have glanced under the bonnet of my 72 TR6, and although I would not
swear to it, the wiper assembly looks like it is die-cast aluminium alloy
(rather than zinc-based pot metal). This doesn't make one jot of
difference to the problem, however, since where ever on the electrochemical
series you will find brass and whatever the threaded bit is, I am sure you
are right: you've got corrosion aplenty in there.
The problem you face with soaking is finding an agent that will disolve
oxides, and many of the non-ferrous oxides are very stubborn. So the
agents are often pretty toxic and caustic (and can harm the parts
themselves). They also have to have very low visocity, since you need the
agent to get into the spaces between the two parts (capillary action will
help, but the fluid has got to "flow" well).
My suggestion is to resort to the standard solution of heating the parts.
A good sized propane torch will usually supply a far amount of heat to the
joint quite quickly. The old problem with this approach is know "how
much." If the wheel box is pot metal, then you cannot apply as much heat
as you could to an alumimium. And even then aluminium doesn't glow very
much before it melts. The MP is quite high thou' and if the alloy surfaces
are clean and shiney, you can smear hand soap on the metal surface, and
heat until if turns black (it will turn to yellow, gold, brown, and then
black). This will give you a good indication of when to stop and then try
getting them apart.
You can repeat
Help!
I'm trying to remove the chrome-plated nut that holds the wiper wheelbox
to the car. The bushing it threads onto (part of the wheelbox) turns
when I turn the nut. Yup, there's corrosion in the threads. But it's not
your Standard Triumph rust. The bushing is non-ferrous (pot metal?). The
nut is chrome plate over brass.
Does anybody know what kind of alien chemistry I'm dealing with? More to
the point, what do I soak it in to loosen the nut? 3 good soakings in
'Snap Rust Buster' haven't budged it, but hey, it's not rust!
This is a replacement wheelbox - I cut the nut off the trashed original
to get it out of the car. Immersion IS an option. But in what?
Bill Kelly
'68 TR250, on the mend
'62 Herald, on the road
____________________________________________________________________________
Anthony Gordon Technology Education Coordinator
Saginaw Public Schools tel: 1-517-797-4855
ISDC, 1505 Ottawa Blvd fax: 1-571-797-4778
Saginaw, MI 48602, USA email: tgordon@saginaw-city.k12.mi.us
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