From: Barry Lovelock
Date: 09 Jan 2002
Time: 08:35:09
Remote Name: 213.1.169.102
I think you need to read the comments below - re steering boxes.
If the A arm broke, then it may have been responsible for some of the bad steering anyway.
Basically, camber and to some extent castor, are factory-set - to whatever they are. Camber is set by the hubs - the king pins must be vertical and the axle eyes so too, until the castor is applied by the A arms and this is set too by the basic placement of the arms on the front cross member (and the end spigots). Twisting the arms to reset castor is a crude non-engineering way to do it and to be despised, but placement in a different position or modifying them in other ways is a good engineering solution. Look if you can, at a picture of Reg Nice's racing Ulster (he has two Ulsters) and you will see the A arms set below the front cross member on a lowering bracket. This car is rock steady at 85 mph ON THE RACETRACK and with 15inch wheels, but racetracks aren't normal roads and at 85 mph in my Ulster on 19inch wheels with 3-50 tyres and standard steering, but twin shockers I am s--- scared! In fact, the twin shocker set-up is fine for the track again, but too rigid for the road as it cause bump-steer due to the whole thing being virtually immovable.
If you look down at the suspension on a non-Girling front axle as you drive (dangerous!), you will see it all move and if you do the same in reverse and brake hard it will all wind up like a clock spring! Its meant to, its made of fag paper thickness!
An important thing to remember about A arms is that the ball on the chassis wears badly and you must ensure the new cups, let alone the old ones, don't bottom on each other without clamping tightly on the ball; just file them down to give some clearance. The spring on the bolt assembly, IMHO is an engineering mistake and I use a proper bolt, not a setscrew, done up really tight, so that the spring does effectively nothing except contain purely the thou or so clearance I leave. If the spring is left to, well, spring, the whole front axle moves back and forth - not exactly conducive to good steering. Remember, much as I hate them, BMW's don't use rubber in their steering gear and that's why most of the opposition feel like jellies!
Finally, my LWB Ulster special is rock steady at any speed, but is as boring as an Anglo Saxon word in it's handing; it understeered terribly when the rear springs were set far too low. When I bent them right down, it became more like the real (SWB) Ulster as it then suffered from rear-end steering. The other thing is it was very safe with 4.50x17 rear tyres, but using 4" section ones the tyre pressures must be 28-30 psi rear and about 18-22 front to prevent terminal oversteer. 4.50x17 are taboo on the front of any A7 btw, even though they are universally used.