Loose and sloppy steering problem? Can`t keep it

Safety Alert
Loose and sloppy steering problem?
Can’t keep it between the lines?
This article contributed by an Aurora owner describes in good detail his project to upgrade the steering
linkage to a more robust alternative which eliminates the “play” and keeps you idriving n the right direction.
PROJECT DESCRIPTION:
Replace two stock universal
joints and connecting shaft.
If you have play in your steering
system now, you will find this
project to be well worthwhile.
ORIGINAL SYSTEM: The car was designed to use a shortened “early” MGB
steering rack and pinion set. The MG steering ratio is quick and the system is (was)
readily available. Aurora shortened the rack housing some number of inches and
also cut the input shaft to less than 4 inches long, from the original 12”, or so.
There are no standard racks that would work on this car. The basic shaft is almost
” in diameter, but for some reason it’s about 16 thousandths undersize. I’m not
sure of the detail, but the shaft was outfitted with a thin bushing over the first inch.
The bushing measures to .749” and that’s the mating point for the u-joint. The shaft
end was drilled for a 5/16” bolt as was the u-joint. Both u-joints are “military spec”
items, meant for precision, light duty use. They are not meant for steering systems
as the design is not robust.
December 2012
Next up the line there’s a light duty 3/4” hollow tube - about 20” long. Again, all it
uses for force connection is a 5/16” bolt through the u-joint and shaft. The upper
end of the shaft mates with an MGB steering column/shaft. This shaft is also
hollow, but appears to be made of stronger steel.
On my car (17,000 miles) several of the above mentioned holes became elongated
and allowed connection movement so the steering system had “slop” in it. Both ujoints were near the end of their useful life as some “slop” was evident.
DISCUSSION OF A FLAWED DESIGN
As mentioned earlier, original provisions were not robust. Holes through tubes are
really not suited to this rigorous use and the u-joints are weak. While the upgrade
described herein is not the ultimate and proper design, it offers some degree of
improvement. The reader must decide on his/herown whether to use this information.
REASONABLE PATH TO IMPROVE THE SYSTEM: A wholesale replacement
of all parts would be preferred, however cost would be high. In my opinion the
highest gain for the money comes with replacement of both u-joints and the
connecting shaft. This does retain the steering rack and the throughbolt method of
securing a u-joint to a shaft. The same thoughts apply to the upper steering shaft. I
believe the two shafts are reasonably sound and can remain. Should wear occur
they can be replaced in kind. Breakage is a remote possibility. Please bear in mind
that I will not be held responsible for failures/problems in other vehicles due to
design/parts/ and-or installation flaws.
DESCRIPTION OF CHANGE:
Borgeson u-joints (#014964) were selected. They come with
a 3/4” “DD” bore on the outher end. The DD geometry
describes the shaft cross section if one were to place two D’s
back to back. The steering shaft is 3/4” high, 1/2” wide and
22” long (Borgeson part #419422). I used plain steel joints
and stainless for the shaft. A hole must be drilled through
each joint for the ¾” round connection shaft bolt.
The new DD steering shaft must be cut a little shorter and
then has to be drilled with shallow dimpled holes for the
joint set screws. None of these tasks are not especially hard
to do, but you may want a shop/professional to do this work
as accuracy is important. Note the steering column housing
connection bolts run in a slot and therefore it is possible to
adjust the steering wheel forward or back, a driver’s choice.
Steering rack input
Steering column shaft
Newly fitted joint and shaft
AFFILIATED WORK: Now is also the time to refurbish the steering rack.
General cleanup, paint, new boots, and lube replacement. Tap out the tie rod ends,
remove the four rack bolts and bring the assembly to a work surface. Keep the left
and right sides identified and remove all parts (see an MGB technical thread on
details here). Mine was in good shape and it was cleaned, painted, and lubed with
grease. There are pros and cons to grease vs. 90 weight oil. You decide.