[TR] TR4 horn wiring

[Dave1massey at cs.com]

In a message dated 8/17/2010 9:38:53 PM Central Daylight Time, 
brad.kahler at 141.com writes: 
> What I think is missing is some sort of grounding wire from the
> steering column to the rack and then from the rack to the frame.  This
> TR4 does have the solid aluminum mounts so I don't know that it would
> need a ground wire from the rack to the frame.  I'm not sure I see a
> need for a ground wire on the lower metal u-joint that ties the lower
> column to the steering rack.
> 


Mr. Brister's solution notwithstanding, the TR6 has a black wire with a 
ring terminal that attaches under the steering rack fill plug.  Since the rack 
itself is mounted via rubber bushings the only ground path is through the 
suspension components which is unreliable at best.  In fact all the attach 
points to the frame are implemented with rubber or nylon bushes If I remember 
correctly.  

Connecting the shaft to the rack housing is problematic in that you would 
need some sort of watch spring arrangement that will wind and unwind as you 
turn the wheel.  I tried that many years ago when my MGB horn stopped 
working.  The wire lasted long enough to get me through my annual inspection but 
not much longer.  As it turns out there was sufficient rust in the U-joint 
connection to prevent electrical conduction and taking it apart and putting it 
back together (I forget why I did it) fixed the horn problem.  So check the 
U-joint of you get no joy.  But the shaft to rack housing connection is made 
by the gears and bearings inside the rack which are bathed in oil/grease 
and should provide many years of trouble free service.

Of course you can bypass all that by using the slip ring solution offered 
by my friend Dave B.

Cheers


Dave