Front Suspension Question

[Mike Wattam <101714.1343@domain.elided>]

Regarding the discrepancy you have noted between your two Stags, clearance
between tyre and damper.

Yes, you should be able to get your fingers between the tyre and the bottom
spring carrier.  Bu it is not too unusual to have a smaller gap.  I have an
uneasy feeling I am about to spend the rest of my life sticking my hand
under Stag front wheel arches - whatever turns you on.

The front subframe is the same for 2000/2.5 (with power steering) and the
Stag, so this is not responsible for your problem.  Even if the position of
 the inner bush is changed, it does not affect the relationship between
damper and hub (see below).  

Likewise the upper mounting and bush.  But check the bush anyway as there
are a lot of sub-standard mountings, the rubber bonding is very bad.  It
doesn't matter which way the spring is fitted in theory, but it is not
unusual for the spring to 'bow' after considerable use, in which case it
should be fitted on the damper with the 'bow' facing towards the tyre, as
the other way round it would rub on the inner wheelarch. 

The position of the wheel/tyre in relation to the damper assembly is fixed
by the 4 bolts which hold the hub carrier (209344) to the bottom end of the
damper assembly.  There is a very small adjustment by fitting shims (0.010"
and 0.004") in pairs to the bolts, as has already been mentioned.  This
adjustment is not for clearance, but to enable the correct camber of 0.5
degrees lean out towards the top.  

These shims were fitted by Triumph on production when the car was made but
in service when the dampers are changed, these shims normally drop out and
become lost.  Frankly, these shims are so small that they will make no real
difference to the tyre clearance (add 0.020" shims = 0.100") at the tyre. 
I also believe it is a complete waste of time fitting these shims as they
are 'no longer available', and modern tyres and road conditions suit more
negative camber than Triumph designed anyway.

So, this leaves you with the problem.  In my view, the problem lies with
either
a.  incorrectly manufactured parts, or
b.  damaged parts.

Then I suggest there are three items which could be causing the problem;
1.  The damper assembly is not correctly dimensioned or the spring bottom
seat was welded on out of line, so the bottom spring seat is closer to the
tyre than it should be (compare dimensions against your 'good' car)
2.  The central pushrod of the damper assembly is bent - this occurs quite
easily in collisions (check this by bouncing the car, is the action of the
damper 'sticky' or leaking?)
3.  The hub 209344 itself has been machined incorrectly (probably on the
taper where the stub axle fits) or has been distorted in use.  The hub is a
malleable iron forging, this is so that a severe blow will merely bend the
forging, and not break it.  It is not unusual for these to be bent from
brute force being used to separate the lower balljoint.
4.  The stub axle itself (154474) may be bent, either from accident or from
a severe 'yump'.

The only way to check the last two is to substitute parts from car to car. 
In any case, if you are stripping the hubs and stub axles you should fit
new stub axles.  This is because they tend to fatigue failure after many
years use, and fracture just inside the hub, in the taper.  

All Digest members please note:
This problem of stub axle fatigue failure is becoming fairly common, the
wheel is restrained by the callipers for a while so it is easy to stop the
car without catastrophy.  I know of only one case (in Germany) of a driver
pressing on regardless of sudden severe front end vibration, inevitably the
calliper was ripped off the hub and a nasty accident ensued.  I have also
examined a number of stub axles removed which have not failed, and found
they can have deep cracks at the point where they eventually fail.

Mike Wattam
Triumph Stag Register