front discs

[Mike Wattam <MikeWattam@domain.elided>]

Hi Brian

Replacement discs (and pads for that matter) are of variable quality.  
This arises from inconsistency in the casting process, 'swash' caused by
eccentric machining, and from thickness variations.  New discs should be
well capable of stopping the car quite easily without very heavy pedal
effort, without readily fading, and with no feedback through the steering
or front suspension at low, medium or high speed.  Bad material may cause
'judder' or 'swash' one day which disappears the next, then returns........

On fitting the discs check for running true within 4 thou (I like to see 2
thou but not always achievable) and if outside limits progressively turn
hole by hole on the hub(s) and check again.  In view of this it is
adviseable to fit new hub bearings, but only after this jiggery-pokery is
completed.

After 'running in' both discs and pads for c250 miles (no heavy braking if
avoidable) check the above quality, and no sooner unless problems become
evident.

In the UK, there is one supplier who can supply ventilated discs, Monarch
(details on request) and twin-pot calipers without any other modifications
to standard components.  I am expecting to be able to report on these soon,
but not sure exactly when.  These use proprietary ventilated discs of high
quality, plus reconditioned Volvo 440 twin-pot calipers via an adaptor
plate to the standard lugs on the stub axle.

Richard Lane (Brighton Stag Specialists) supplies an altogether heavier
duty kit which requires stub axle modifications plus alloy wheels and is
suitable for large power increases, plus will enable you to weld your nose
to the windshield under emergency braking conditions.  This ideally should
be used with his rear disc conversion.  The body and you could leave the
wheels behind with this lot!

However, I am one of those who believe the Stag brakes are more than
adequate when in good condition, the thing which makes them very heavy and
inclined to fade is that (on the Stag for some reason) on the inner wearing
face the discs tend to corrode very badly and this gives quick overheating,
fade and thus a stupidly heavy pedal, all this exacerbated by ridged
wearing surfaces.  What the Stag really could do with is a bigger servo
(BMW 5 series up to 1995 does nicely) and ABS (no chance!).  So, to vastly
improve your worn brakes, just fit good quality new discs and pads.

I am also unconvinced that ventilated discs per se are a good thing.  In my
experience on a number of cars, the thin-ness of each 'plate' is quite
thin, and it only takes one bout of intensive severe braking to cause them
to distort and thus need renewal.  Also ventilated discs need replacing
when worn less and must NEVER be re-ground unless specifically approved by
the manufacturer and then only to restore 'swash'.

Sorry, what was the question?

Mike Wattam
Chairman - Triumph Stag Register