One of the better diagnostics I've found on the web is at:
http://yallara.cs.rmit.edu.au:8080/~mg/cars/goblins/tech/frontend.htm
From that site, here is the front-end test:
Spridget
Front Suspension
Gillspeed
Spridgets are enjoyable to drive for a number of reasons, but one of
the foremost must be the very nimble steering. Nimble that is if you
have maintained it well, dastardly and twitchy if you or
the DPO have let it go too long between visits to the workshop.
Below, I have outlined a series of inspections to do on your car to
decide if it is time for new suspension or brake components.
King Pin End Float
With the jack under the jacking point, lift one front wheel
clear of the ground. Try and move the front wheel up and down, if
there is any up and down movement and some "knocking"
noises, you have king pin end float. Remove king pin shims to tighten.
Lower Outer Wishbone Pin
Place a chassis stand or jack under the lower wishbone and
raise one front wheel clear of the ground. Again try and move the
front wheel up and down, if the kingpin moves up and down
relative to the wishbone, the "lower outer" pin and wishbone
bushes will be worn. It is not uncommon for the "lower outer" pin to
waer through the top of the wishbone! If you remove
the allow plug and grease nipple, the extent of the wear will
be obvious. This wear is dangerous and needs urgent attention!.
A less common problem is loose or missing cotter pins. Up and
down movement of the kingpin relative to the wishbone will again be
present because the "eye" of the kingpin has has
been worn oversize.
King Pin Bushes and Wheel Bearings
Hold the wheel top and bottom and rock the wheel in and out.
Any movement suggests worn king pin bushes or worn wheel bearings.
Have an assistant apply the brakes hard. If the movement
dissappears the wheel bearings are worn, if not, it's king pin wear.
If you can see no movement in the lower kingpin bush,
check the "upper outer" shock absorber arm bushes for wear.
Also, while the brakes are still applied try and rotate the wheel
backwards and forwards. If you get a "floppy" sort of
rotation movement, this confirms your "upper outer" shock
absorber bushes are worn, and even worse, your shock absorber lever
arm may be lose on its shaft. Both of these items need
immediate attention, especially if your car is twitchy under brakes.
Ties Rods and Steering Rack
Remove the road wheel and rotate the outer tie rod end (i.e.
tilt the rod end fore/aft). It should be stiff but not notchy. There
should be no in and out movement.
Check the rubber gaitors on the steering rack and replace
these if there are any splits or cracks. If you don't, you will soon
be up for a replacement steering rack!
Brakes
Check the front rubber brake hose. They often run on the tyre
when steering is on full lock. Check brakes for wear, shock absorber
bolts for tightness, also check for fore/aft movement
of the shock absorber arm, especially, on the inside end.
Check the metal hydraulic brake line on the chassis for kinks. Look
for leaking hydraulic joints and cylinders.
Check wheel studs for stetching, check steering arm to kingpin
bolts for tightness.
Front Shock Absorbers
Refit wheel, drop car back onto the road and bounce the front
muduard. If it bounces freely, reco shocks are in order.
Gillspeed is a specialist Spridget and MGB supplier (new and 2nd hand
parts) and workshop here in Victoria. Bob Gill started Gillspeed back
in 1974 and offers overnight service
throughout Australia.
--
__________________________________________________
Jeffrey H. Boatright, PhD
Assistant Professor, Emory Eye Center, Atlanta, GA
Senior Editor, Molecular Vision
<http://www.molvis.org/molvis>
<mailto: jboatri@emory.edu>
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