DIY FRONT WHEEL ALIGNMENT
By Karl
Schluter.
The front on our cars cannot totally be adjusted.
However some adjustments methods are given, these are handy if the car is being
re-bushed or a tire rod is being replaced etc.
CASTOR:
Caster is the self-steering effect caused by the position of the strut centerline, much like the annoying shopping trolley!
Caster is fixed on our cars however the use of
homemade shims made by washers will allow some adjustment. Installing them in
front of the track arm at the sway bar junction and removing the same from the
rear side of the arm will reposition the strut via the track arm. In extreme
conditions the sway bar could have more threads tapped further up its forward
end if needed. I have seen the “U” bolts of the front sway bar
clamps repositioned to move the struts in turn too. However I don’t myself trust this method, maybe
filing factory like notches in the front section of the sway bar near its front
bends would help the adjustment stay. At this stage I feel I would be looking
more at why the factory setting is not available.
CAMBER:
Camber is negative when the outside top of the wheel
tilts in compared to the outside bottom of the wheel. Positive camber is the
outside top of the wheel being further out than the outside bottom of the
wheel.
Camber is also not adjustable on our cars, often
nothing can often really be gained by slotting the strut top mount areas, I
would look at adjustable strut top hats which would enable caster adjustment
too however on some cars the springs are very tight under the strut tower area.
Custom struts with smaller diameter springs like used in the article on
lowering our cars (photos by Ade) would help in this area with adjustable strut
top hats.
I myself run the tried and true camber pins. These
are eccentric in design and replace the inner track arm mounts. Be careful when
making these as I have found different tapers on different cars within the same
mark. (Plans on site for the camber pins and also an article about making an
adjustable track arm).
I have run camber pins on my V8 powered car under
hard use for 20 years with total reliability.
I run no more than ½ degree negative camber on both
sides at the front as more made my car loose under hard braking.
TOE:
Toe is whether your front (or rear) wheels turn in
(or out) at the front. Tires wear fast if this is incorrect (note to avoid
kerbs!).
The toe is of course easily adjustable (finally!) and
I usually run 4-5mm toe in with the common setting being 1/16” to 3/16” toe in (this means that sitting
in the car the front wheels are turned is very slightly together at their
front). Two types of jigs as shown can be made and used, depending what materials
you have on hand. Use something that is stiff and won’t bend if lifted on its own. A
lock bolt tapped into the outside tube or arm (or a nut welded over a drilled
hole on the tube/arm then a bolt screwed in) allows for the gauge setting to be
locked once set.
To check toe a few things need looked at first:
All ball joints must be tight and greased if
possible (replace any damaged rubber boots).
All wheel bearings should be adjusted correctly.
Both sets of inner and outer tie rods should over all
be the same in total length and their clamps or sleeves tight and sound.
Note the above is important for good cornering and
tire wear as the front wheels need to turn together in the correct curve, this
is called the Ackerman effect. Once the two tie rod sets are the same length
your steering wheel may need taken off and put back on in the now correct
position.
If adjustment needs done, adjust both tie rod pairs
on either side to be the same once the final correct toe in is set. (GM Holden
HQ tie rods can be used in Mklll cars with some work; they are a lot cheaper
and stronger too).
With a helper and the car on level ground and wheels
steering straight ahead, measure the outside rim edge half way up the front
wheel at the back, side on, (inline with the centre of the wheel) from outside
edge to the other sides front wheels outside edge and set the toe gauge to that
setting (B).
Then carefully bring the jig out from under the car
and compare the measurement this time at the far front outside edge of the rims,
half way up the front wheels again (A).
To be correct the far front measurement (A) should
have a gap from any one (only one) sides pointer to its rim that matches the
factory spec-ed measurement (or use the quoted 1/16” - 3/16”measurement for a start).
The aim is to have the front wheels turning into
each other by the set measurement.
If adjustment is needed adjust the tie rods keeping
both sides of tie rod pairs the same total measurement. Roll the car a few feet
back and forth to centre the front wheels after adjustment is done when
rechecking the toe.
I do my own alignments for toe and the car has
always been spot on when viewed on computer equipment.
Disclaimer:
The advice and guidelines given in these articles are given in good faith.
The owners and managers of the Galeforce Zephyr site will take no
responsibility for any injuries or loss sustained while carrying out the
described tasks and procedures or any consequences arising. Please read
the Safety First
Article