Knowing
that the ball joint on the front end of the drag link was a little worn, I
thought I better do something about it even though the car did not exhibit any
tendency to wander.
The Drag
Link is the rod which connects the arm which comes out of the steering box to
the arm attached to the offside front hub and transfers the effort from the
steering box to the front wheels. Forgive me if you knew that already but if you
didn’t, or were not sure the whole technical tip could have lost its appeal!
However,
back to the drag link with its ball joints. There are two of these on the drag
link, strangely enough, one each end. The ball is attached to the steering box
arm and to the front hub arm, the sockets in which the ball pivots are within
the tube of the drag link.
Each socket
consists of two bearing rods which fit inside the tube, are convex at the end
and hold the ball into the socket. One bearing rod is fixed to the drag link
tube and has a nut and bolt which passes through it and the outer cover.
The outer
cover slides onto the end of the drag link tube holding the outer bearing rod in
place and incorporates a spring.
Back to my
joint, it had a small amount of play in it so a shim or two to increase the
spring pressure would resolve this, or so I thought.
When I
assembled my joint without the cover I was able to compress the spring into the
joint level with the end of the drag link tube without too much undue pressure.
No matter how many shims I included in the joint they would only have any real
benefit if they could go inside the tube.
The answer,
place shims (or in my case a small washer) inside the outer bearing tube (which
is partially hollow to hold the spring) before inserting the spring. Now when
the bearing assembly is put together the spring is further compressed and hold
the joint much tighter.
The purpose
of the spring is to make sure that the joint is easy to move over the whole
range of its movement. If, as in my case, after many years of use the ball is no
longer spherical but has flatten faces the joint would become very tight at the
extremities of its movement.
Special tools
It is also worth noting that it is a very difficult joint to assemble on your
own as you have to push the end cover on to the tube, overcome the spring
pressure, line up the fixing holes and insert the bolt.
If you are
on your own you will most likely have to rig up some way of compressing the
spring with a sash clamp or something similar.
On the
other hand you could make use of a special tool available only to club members
which slips over both ends of the drag link and with the use of a screwed rod
you can press the end cap onto the arm and slip in the bolt.
It should
be noted that no greasing provision is included in the construction of this
joint but the joint should be greased regularly. If there is not one
already fitted, then it is worth adding a grease nipple to the assembly to
ensure adequate lubrication.
This article, written by Malcolm Watts, originally appeared in CA7C Seven Focus in
Sept 2000 pp12-13.
