While all of our T’s have hydraulic dampers, I believe it to be one area
that does not get much in the way of maintenance or service. We all know
the symptoms of a bad one; here are some tips to improve yours! Since a
worn out shock is not serviceable by the average home mechanic, preventative
maintenance is useful in extending the life further of these components.
Bouncing on each fender will quickly tell youif a shock is bad or needs
service. If it is leaking and you have filled it before, most likely it is
shot and needs rebuilding by a qualified rebuilder of these units. A way to
check a non-leaking shock is to separate the shock arm from the top trunnions
and move it through its full travel or better yet, remove the shock
completely. Do this safely and refer to your shop manual for the procedure
to release the shock arm or to remove it from the chassis. Assuming you have
removed the shock, secure it in a vise and move the arm through it’s full up
and down travel. You may notice weak spots or inconsistencies in the
resistance as you move the arm.
The main thing we are trying to do here is to clean out the chambers and remove old hydraulic
oil and filings and deposits. Remove the top filler plug and the valve
assembly under the arm. Gently remove the cover plate if fitted. Drain out
all the old fluid while exercising the arms through the full stroke.
Inspect the inside of the shock body as well as you can to see if there is
any obvious damage or wear. Once drained, refit all the covers and plugs
and fill the chamber 12 with kerosene. Next work the arms to move the
kerosene around to flush. Remove the valve and top filler plug and drain out
the kerosene and then repeat the process 3 or 4 times until you are
satisfied that you are not getting any further debris. Drain all the
kerosene to make sure that there is none remaining. Inspect the valve
assembly for cleanliness but do not disassemble it. Adjustments to the
valve are outside the scope of this article. Make sure the valve assembly
is reinstalled as it was originally. Reinstall the remaining parts and fill
the body with the recommended shock oil or SAE 30w non-detergent oil. Fill
the chamber and work the arms several times to expel any air. Refit the
shock and check the level once more. It should be about 5/8” from the top.
That’s it. This can be done to any Armstrong shock. Be aware that like most
old things, disturbing the “dirt” may cause a problem in a working, but very
marginal part. You may end up having them rebuilt anyway. Such is the life
of a 50 year old part!
Information for this article came from Internet searches and personal experience.
New Fangled Timing Lights
Some of you no doubt have seen and used the relatively new inductive
dial-type ignition timing lights. I have a Sears unit, which I have found
to be quite useful, especially with engines that do not have any type of
timing marks on their crankshaft pulley other than a notch at TDC.
To use this type of light, hook up as you would normally. Let’s say you want
10°. BTDC. Turn the knob to 10, run your engine at the specified idle
speed for timing checks. With the light aimed at the mark, adjust your
distributor until the mark in the front cover lines up with the notch in the
pulley. Snug up the distributor clamp. Simple as that! You can do the
reverse too if you want. Let’s say that you are pleased with the way your car
is running. Using this light set it to 0 then rotate the knob while you
are idling the engine. See what reading you get, that is where the timing
is now set. Note that setting, along with your idle speed and you should be
able to replicate that setting again if you have the need to remove the
distributor. This can be useful in determining maximum advance and a worn
distributor shaft. With a worn distributor shaft, and any timing light, the
mark on the pulley will be seen to jump around a bit, indicating changes in
dwell, affecting ignition timing.