Much chatter lately on rear springs. This is another alternative as
provided from the Triumph Maintenance Handbook on the VTR home page --->
Larry Quirk
Air Shocks for a Triumph Spitfire
by Charlie Brown
cb1500@erols.com
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Not long ago, when I launched my second Spitfire as a daily driver, I found
it too suffered the same malady as other Spitfire 1500s; a sagging rear
end. After trying to cure the sag problem on my first Spit with a re-arched
rear spring, I finally ended up replacing the OEM Girling rear shocks with
a set of Monroe air-adjustable shocks.
By increasing or decreasing the air pressure of these shocks, I not only
can increase the load capacity of the trunk (in a Spitfire??) for
overnighters, but I can also maintain proper camber angle for normal
everyday driving.
My first set of these shocks was installed in 1990 and they're still
working properly. Even though that car is not may daily driver, during
warmer months it has been autocrossed on a monthly basis.
Try not to misinterpret the purpose of this modification. although it will
help support the rear end, which on a Spitfire is woefully weak, it in not
intended to replace a badly worn transverse leaf spring. If the spring is
shot, replace it then use these shocks to fine tune.
Another question I hear a lot is why Spitfires always seem to sag more to
the drivers side. I have a theory. If you think about it, the average male
driver accounts for about 1/10 of the Spitfire's total rolling weight,
that's always offset to one side. That's bound to upset the geometry. To
check the "set" of your spring, roll the car back and forth on smooth level
ground. If the car returns to a fairly normal attitude, the spring is
probably still in serviceable condition. If the car maintains a decided
list to port, the spring may have taken a set. Swapping the spring
end-for-end could extend its life. Once both rear wheels take on that
hideous 7-8o negative camber, think about replacement.
The air shocks I've used are designed for 1963-82 Corvettes. Their
compressed and extended lengths are close to Spitfire OEM, with the
air-adjustable units extending about 1-1/2" longer. The top and bottom
mounting eyelets are identical, although a rubber bushing swap will be
needed. And best of all, no modification to the car is needed. Both Monroe
and Gabriel kits include two shocks, tubing, connectors, routing clips, and
inflater "T".
The Monroe kit number is MA 785. When I spoke to Monroe Customer Service in
the Fall of 1995, they had no plans to discontinue this number. Their list
price for the kit is about $170. Our local discount auto parts supply could
special order the kit for about $88, delivered in 2-3 days.
Good ol' JC Whitney (312-431- 6102) carries what I believe is the Gabriel
cross reference (there are no brand names on the packaging or the white
painted shock itself, and Whitney would neither admit or deny the Gabriel
connection). Whitney's catalog number is 81-3388Y. Remember, tell them it's
for a '63-'82 Corvette (pick a year) or the phone representative will go
into a tail- spin trying to figure why you want to order Corvette parts for
a Spitfire. Cost is about $75, delivered to the east coast in about 7 days.
When I installed the Monroes, it was necessary to remove both upper and
lower bushings and reuse all four of the stock Spitfire rubber cones. The
Gabriels come with a lower bushing that slides right onto the stock
Spitfire mounting post; the upper bushing needs to be removed and replaced
with two stock cones. The Gabriels may also require a thin washer slipped
onto the lower mounting post first to provide a little extra clearance from
the vertical link (conveniently provided in the kit's hardware baggie).
Hint: A little silicone spray goes a long way in easing re-assembly.
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The air lines that come with either kit are long enough to route just about
anywhere you chose. On my latest conversion, I ran the air lines from the
shocks, up through the rubber bushings already in place for the fuel (left
side) and vapor recovery (right side) lines in the floor of the trunk. In
either case allow a little slack for movement.
My "T" filler valve was mounted in a 5/16" hole I drilled through the top
edge of the panel that covers the fuel tank, on the trunk side. Check for
kinks and clear routing of the air lines before and while reattaching the
panel. Like I said before, the air lines are long enough to route just
about anywhere; put the "T" valve where it's convenient for you.
That about it for installation. After lowering the car off the jack stands,
take a peek from below to check for reasonable slack in the air lines. In
both my Monroe and Gabriel installations, I've had no clearance problems
with brake lines or vertical links. However, with the addition of various
aftermarket parts, clearances may change. Check it!
Both of my Spitfires carry about 45 psi for everyday driving and about 55
psi for road trips with luggage and a passenger. If you want to get fancy,
you could adapt individual Schraeder valves for each side and really fine
tune your camber. Just add a little pressure to raise the rear, and bleed a
little pressure to lower it.
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