The nut sizes are variable depending on car and originality and which
bit of exhaust. Common sizes are 13, 15 and 17 mm, some vehicles need
special spring-clamp removing pliers.
As to separation: With the right tools and experience most exhausts can
be dismantled for re-use, if they are not too rotten. If you are
replacing the back section of exhaust it is often best to cut the pipe
just after the join, slit the remaing stub and twist it out.
If the joins are 'slide one pipe inside another', then after loosening
the clamp spray liberally withe rust dissolver and leave for as long as
practical, give the exhaust join a good tapping with a hammer before and
during the soaking, then try and wiggle the exhaust apart, once you get
the tiniest bit of movement you are on the way. Other ways to get it
started involve heat from a blowtorch or induction heater or an air chisel.
Seriously stuck exhausts may even have to be cut apart and rewelded as
needed. Another method that I sometimes use is to extend the join slit
of the outer pipe to relieve the tightness, pull the exhaust apart and
weld the slits up again, there are also various air chisel ends to take
exhausts apart, plus specialised thin curved chisels which can open up
The difficulty of separating exhaust components is why most exhaust
places do not bother and just fit the whole lot after cutting the old
off as needed.
You would really struggle with an arc welder on normal exhaust,
particularly as the metal gets older, rustier and thinner. Mig, tig or
oxy-acetylene would be first choices, unless you are really good with a
stick welder and used to such thin stuff. I am lucky enough to have all
available, but I cannot remember the last time I got the stick welder
out of storage to use it (probably thirty years) and would not even try
it on anything normal unless there was absolutely no alternative.
On Sat, 06 May 2017 17:16:17 +0100, MrCheerful wrote:
I still keep an Oxford oil cooled 300 Amp job, though. For heavy plate
you can't beat it. Many times over the years I've needed to knock up a
jig or a hydraulic press or a vehicle stand or whatever that requires
strong jointing of thick steel parts, and there's simply no comparison.
For normal everyday fabrication up to half inch stuff, the Mig is fine,
luckily enough I rarely need to use anything even approaching the total
capacity of any of the sets I have. I did use big arc sets years ago,
but have had no need since.
I have a tin made by pattex, it came from a Lidl store, but not usual
Vinegar is actually a good rust remover, and everyone has some of that,
and it's cheap!
WD40 would be better than nothing.
I used to get a product called Lusol which was very good, despite the
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