[TR] Ref: : TR4 suspension mods

[Q]

The later style upper suspension arms place the caster at about 3 
degrees.  The trunion is also different to allow for this added angle.  
The added caster makes the steering more self centering.

The older style suspension, as used in TR2/3/early 4 has 0 caster angle 
which makes the steering lighter when moving slowly such as parking.  I 
always thought that the earlier cars with worm and sector steering boxes 
had heavier steering thus the low caster angle.  The TR4 has rack and 
pinion steer starting with CT1 which is easier to steer at low speeds so 
they added caster to make the car easier to drive at speed.  They 
changed the ball-joint style at the same time as well.

You will need to use the correct trunion for the upper wishbone type or 
you will preload the heck out of the suspension parts causing early failure.

Edward Hamer

Petaluma CA