Subject:
Narrowcase
single shocks
Date:
Sun,
29 Jul 2001
10:29:17 +1000
To rebuild
your shocks
you will find if you make something similar
as shown in
the attachments
makes a tedious job painless.
Being
constructed in an
" upside down " manner makes the reassembly
a four
handed affair
without a jig. With the jig it takes but a few moments
to get the
job done.
My tool
came out a
little different but works the same. Be
sure to round and smooth the underside of the cut out of the tool that
contacts
the bottom alloy cover, I also covered the edge with electrical tape.
inspect them
for damage.
There are four nylon guides on the lower alloy
shroud to
protect that
body from scraping directly on the steel upper
shroud. If
any of the nylon guides have worn away you
will need to have a
small piece
of nylon on
hand to "weld " on. That is use some heat to melt
the end to
secure it. I
use a soldering iron!
I used
that yellow weather
strip glue, gorilla snot.
The springs are
often rusted and look
bad - this is not a problem.
All you need
to do is
clean the rust from them and coat with a zinc based or
galvanizing
paint. There
is really no need to rechrome them, you can't see
them anyway!
Be sure
that the free length is the same on both springs.
Cleaned
the springs
and coated with grease.
Next inspect the
shaft, this should
not have any score marks and be
perfectly
straight. If it
is scored you would need to have it hardchromed
and ground,
this is
expensive. Best to try to find another shaft, measure
the length
and the shaft
diameter to ensure the correct one is sourced -
there are a
couple of
different sorts. Shafts come in 9mm and 10mm as well
as a couple
of different
lengths.
I had 8
shocks, I got them really cheap. I used
the
best parts from all to make a pair.
You will want to
replace the seals,
which are unobtainable ( at
least here
in Australia
) A double lip hydraulic seal can usually be
obtained in
the correct
shaft diameter and the depth, the width will need to
be a
compromise. My
solution is to machine the seal holding collar to an
available
seal size. Be
careful when removing the old seal not to damage the
seal holder,
these
aren't so easy to machine up!
I found
the seals at
a local supplier but I didn't want to machine the shocks.
My rebuilt ones don’t leak so far.
When reassembling
the piston components
on the shaft do not
over tighten
the end
nut. There is a series of discs which operate as rebound
valves and
if crushed
you will have no rebound damping, which is the main
operation of
the shock.
Take care too not to mix up the order of reassembly
of the
piston and valves,
shims.
Take
pictures, make
sketches, take more pictures!
In refilling the
shock with damping
fluid ( oil ) I have taken the
advice of
Henry Hogben
in Canada, 50cc of 5w oil. You can experiment with
this to the
extent of
changing the viscosity up to 10w. Phil Hitchcock
recommends
60-65ccs of
oil, I don't subscribe to this one, it seems too
much. Have
the piston
assembly at the bottom of its stroke when refilling.
Then tighten
up the seal
collar, again don't over tighten, using a new o ring
for the seal
between the
collar and the shock body.
Regards
Richard
Kennedy