Customer Service
24 Hour Fax Machine
Canada Wide Toll Free Order Line
1 (519) 337-3232
1 (519) 336-5936
1-800-265-743 7
9
Symptoms
-Hard Steering-greater than normal effort required
to turn the steering wheel, particularly at low speed.
This can be difficult to determine since the problem
often develops very slowly, over a long period of
time.
-Excess wheel squat. Do the front wheels appear
to camber out?
If you look straight at the front wheels from in front of
the car, the wheels should appear to be straight up
& down. If the tops of the tires are closer together
than the bottom, the kingpins are probably worn
out.
-Excess tire squealing while cornering at moder-
ate speed.
-Excess vibration in the steering wheel.
Note: tire imbalance or a bent wheel can also cause
this. In fact we have seen this attributable to bad
driveshaft U-joints in rare instances!
Potential Wear Points In The front Suspen-
sion:
-Kingpins & their supporting stub axle bushes.
Failure to grease kingpins regularly will cause the
stub axle bushes to wear badly where they con-
tact the kingpins.
-Lower trunion steel sleeve & lower trunion bush.
Regular lubrication is critical here!
Failure to lubricate this point always results in dis-
aster. The lower trunion bush wears. The trunion
bolt seizes to its steel sleeve. This causes the
kingpin assembly to pivot on its mounting bolt rather
than the sleeve and trunion bush as designed.
This quickly "trashes" the lower control arms by
elongating their kingpin retaining bolt holes.
-Lower control arm rubber bushes.
These bushes fail over a short period of time &
cause excess wheel camber. The original bush
design is soft rubber. Deterioration of the rubber
causes the bushes to break apart and fall out of
position between the fulcrum pin and lower control
arms.
We offer a much stronger & longer lasting bush
with a steel insert for improved durability.
The fulcrum bush in the bottom of the kingpin
shown here is almost worn right through on the
lower left hand side. The bush has become oval
shaped, instead of round, as it should be.
It just goes to show you how important it is to grease
that bottom 'Zerk' fitting on the kingpin once in a
while!
Look how badly the bearing surface for the
lower stub axle bush is worn on the bottom
kingpin.
Compare it against the same area on the new
kingpin above it. This will cause significant tire wear
and poor driveability!
Doing the job
The front end of the car must be jacked up. Sup-
port the car on proper safety stands. Unbolt &
remove both front wheels.
Unbolt both brake calipers and support them out of
the way. This can be done with wire. Do this in a
fashion that will not allow the calipers to strain their
fluid hoses.
Unbolt and remove both outer tie rod ends from
their steering arms.
Support the lower control arm with a jack or stand.
Remove the castellated nut & cotter pin, which se-
cures the upper trunion, to shock arm bolt. If you
are lucky it will be possible to pound (or should we
say tap) this special bolt out. If it moves continue to
hammer it until the threaded end is flush with the
shock arm. Use a large pin punch to completely
remove this bolt.
If you are unlucky and the bolt will not move go to
plan 'B' and here it is:
Use a hacksaw to cut the bolt. It will be necessary
to carefully saw down in the narrow gap between
the upper trunion and the shock arm. You will
need to saw through the bolt twice, once on each
side.
After removal of the bolt by either method, the sus-
pension assembly will drop a few inches under the
force of spring pressure. Once this occurs, spring
tension will be minimal, negating danger inherent
in compressed coil springs. Put simply, once this
happens there will be no safety hazard from the
coil spring!
Here is a typical MGB kingpin with the bottom bolt
& bushing seized.
You can see what a rusty mess it is. The slot you
see in the bolt is where I cut through it with an angle
grinder! Grinding thru the bolt and then breaking
off the head will allow the kingpin assembly to come
free of the lower control arm when faced with parts
that are all seized up.
It is now time for your next challenge.
Remove the castellated nut & cotter pin (split pin if
you will) from the lower trunion bolt. This is the
large bolt that secures the bottom end of the kingpin
assembly to the ends of the lower control arm.
Using a BFH (large hammer) attempt to pound the
bolt out. If you are lucky it will slide right out. This
is usually not the case. On most cars the bolt
seizes solidly to the steel sleeve that it passes
through. Since the control arm bolt holes are not
large enough for the sleeve to pass through, the
whole assembly presents a big problem to take
apart.
This is where the operation becomes rather messy.
If you have a cutting torch you can cut the old
kingpin into several pieces. If you cut the lower
trunion area, cutting close up to the control arms,
the bolt and sleeve will disintegrate and fall out of
the way. If you are not so fortunate and do not
have a torch you can still get things apart. Use a
hacksaw or angle grinder to cut the outer ends of
the control arms off, where the trunion bolt passes
through them. Obviously this will destroy the con-
trol arms but they are probably worn beyond re-
use anyhow. (We have new control arms on sale
at very reasonable prices now).
In any event the kingpin, stub axle assembly, and
brake disc will be separated from the car and can
be taken to the bench.
Remove the grease cap, cotter pin, and castel-
lated nut from the stub axle. Lift the brake disc
complete with hub & bearings off the stub axle and
set aside.
Clamp the bottom of the kingpin in a vice. Remove
the top nut off the kingpin. It may be very tight
requiring an impact gun or heat. If necessary cut it
off since kingpins will require renewing.
The upper trunion must now be removed from the
top end of the kingpin to allow further disassembly.
Insert a stout steel bar through the hole in the side
of the trunion. With the kingpin tightly clamped in
the vice, attempt to wiggle the trunion back and
forth until it breaks free of the kingpin. Eventually it
will be possible to slide the upper trunion up and off
the kingpin.
If the components are solidly locked together, the
judicious application of heat from the torch will help
loosen things up.
After the upper trunion is removed, the stub axle
assembly can be slid up and off the exposed end
of the kingpin.
The kingpin is of no further use and should be put
in the garbage (or recycling facility).
Squeeze together the halves of the stub axle-seal-
ing tubes and carefully pry it out of the back of the
stub axle. It consists of two steel tubes that slide
inside each other, held apart by a coil spring. The
seal generally is reused after thorough cleaning.
Be careful not to damage it by careless prying
during disassembly. It is not included in the sus-
pension rebuild kit.
Using a press, remove the two stub axle bushes.
These are steel bushes pressed into the two stub
axle holes, which support the kingpin. New bushes
are included in the rebuild kit.
It is now time to begin cleaning parts. Thoroughly
clean the stub axle assembly in solvent. Remove
all traces of grease dirt, and rust. If facilities exist
the stub axle can be abrasive cleaned (sandblast,
bead blast, or media blasted). If the stub axle is to
be abrasive cleaned it is imperative that the wheel-
bearing surface is first protected to avoid pitting.
Once the stub axle has been scrupulously cleaned
it must be inspected. Check for any sign of crack-
ing, collision damage, damaged or stripped threads,
or wear in the wheel bearing area. Damaged
threads can be repaired by a competent machine
shop. Other damage requires that the stub axle be
scrapped and replaced by another.
After cleaning we suggest a good coating of black
enamel. Painting will be one step on the way to
making your car concourse or suitable for show-
ing.
Painted suspension components will rust far less
than bare ones.
Assuming that you have purchased a front sus-
pension rebuild kit it is now time to dig out the new
stub axle bushes. Each stub axle has a larger
lower and smaller upper bush. These must be
carefully installed using a press. Press the new
bushes into position in the stub axle. Pay close
attention that the lubrication holes in the bushes
match the grease holes in the stub axles. Failure
to do this will make lubrication impossible! They
are a light interference fit. This is required so that
they are held solidly in position.
After installation, the stub axle bushes must be
reamed or honed to fit the new kingpins. People
often ask why this is necessary. The question
often asked is why the bushes are not pre-sized to
fit the kingpins properly by the manufacturers.
There are a couple of good reasons for this:
Remember that a good, tight, suspension will re-
quire a maximum of only a couple of thousands of
an inch (and preferably less!) of clearance be-
tween the kingpins and their stub axle bushes.
Any extra play here will literally make for loose
front wheels!
When the stub axle bushes are pressed into the
stub axle casting, they crush slightly. In fact the
inside diameter of the bushes will decrease a small
amount as the bush is forced into the stub axle.
The holes for the bushes can vary slightly in size
which means that the amount of crush also varies.
Even the bushes themselves have a production
tolerance that allows their size to vary slightly dur-
ing manufacture.
After installation, there are two ways to properly
'size' the stub axle bushes. The preferred method
involves running a special kingpin reamer down
through the stub axle. This reamer tool is specifi-
cally designed for sizing the bushes in an MGB
stub axle.
The alternative method of sizing stub axle bushes
involves using an adjustable reamer or hone. The
bushes must be machined in small increments while
continually testing the fit with a new kingpin.
This alternative method is a definite second choice
as it is difficult to keep the bushes concentric with
each other. Using the correct MGB kingpin reamer
assures concentricity of bushes and exactly cor-
rect bush diameter since the reamer tool incorpo-
rates a pilot and has reaming flutes of predeter-
mined size.
Once reaming has been completed, the stub axle
must then be washed thoroughly in clean solvent
to remove any 'swarf' from the reaming operation.
The spring-loaded seal must then be installed and
seated in position in the back of the stub axle cast-
ing. It must be fully seated to ensure that dirt will not
enter the bushing area.
After installing the lower stub axle seal, the new
kingpin can be inserted up into the refurbished
stub axle.
The brass thrust washer and an adequate number
of steel adjustment washers (from the suspension
kit) should be placed onto the kingpin, above the
stub axle. The upper trunion should be prepared
the same as the stub axle was. It should be cleaned
and painted. When ready it can be pushed down
over the top of the kingpin. You will need to experi-
ment with differing numbers of shims underneath
the upper trunion to bring the 'end float' between
the stub axle and kingpin into correct specification.
This operation is tricky because the ideal amount
of end float on the kingpin assembly should be
almost zero. The stub axle should rotate freely on
the kingpin, but with no perceptible end-float.
The self-locking nut can be installed to lock the
assembly together.
The kingpin assembly should now be set aside in
clean storage while the rest of the suspension is
prepared.
Lower Control Arms & Fulcrum
Pins
At this time the lower control arms and coil springs
should be removed from the car. Pushing the
outboard ends of the lower control arms down with
your foot will usually allow the coil springs to be
pulled out by hand. If necessary, pry them with a
crow bar.
Remove the two bolts retaining each control arm
half to the spring pan. On cars with front sway bars
it is also necessary to unbolt and remove the sway
bar end links.
The spring pan will now drop out leaving only the
control arm halves attached to the cross member
mounted fulcrum pin.
MGB Front Suspension & Steering
Components
It has been a full year since we've had a sale on
MGB front end parts.
There have been supply problems with some of
the components. We have just received several
shipments and we now have all the important stuff
in stock again.
-The Suspension/Kingpin Kits are back in stock
now.
-We just received a heavy crate full of rebuilt MGB
front shocks.
These shocks are properly rebuilt using
stainless steel shaft repair sleeves. The
rebuilder claims that they "can't leak". (Of
course we all know that can't means
probably won't…)
-Once again we have good quality steer-
ing rack gaiter sets. Ten years ago we
never had any problem with steering
rack gaiters. Too bad that things changed!
Recently we had gaiters that were too
short, or suffered from cracking and early
failure.
-Those funny looking spring loaded seal
tube sets in the back of the kingpin were
out of stock for a long time.
We have lots of them at great pricing now.
All 63-80 MGBs use an identical front suspension.
The kingpin type front suspension used on the
MGB is a good design, but it can and does wear
out.
Rebuilding the front end is a rewarding, yet some-
what challenging job for the 'home mechanic'.
It will take the average enthusiast several days to
do a really first class job.
How do I know that my suspension is worn out &
requires service?
. . . continued on the next page
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