The brake reaction bars (or Upper Cross Axle Braces, as they were once known) address the movement of the top of the suspension pillar and locate it with respect to the chassis. There is already a brace from the bottom of the pillar back to the chassis to locate that end. However, under hard braking, the top of the kingpin assembly moves ubder that force to ill effect. There are two basic sources of this movement; (a.) the action of the suspension itself, particularly on washboard surfaces and (b.) rotational reaction from braking stresses.
I must admit that when I first put them on our DHC back in 1959, I had never even heard of brake torque reaction. I was addressing the movement on uneven surfaces which (in addition to making the steering a bit vague) caused cracking of the front wings just inboard of the wing lamps due to movement of the wing stay attached to the top of the pillar. These cracks began to appear within weeks after we bought the car.
I asked Chuck Talbott (then Tech Editor of the Morgan Plus 4 Club) and he told me that all of the racers had installed a brace from the top of the pillar to the chassis where the damper blade is attached. I built them myself (as well as for all of the Morgans I have had through the years). All were made from aluminum and I used thin wall electrical conduit tubing.
After cutting approximately to length (a little long), one end is flattened with a hammer on an anvil (or the end of a vice) and drilled to take the oiler bolt at the top of the king-pin. This is then bent to the angle required, the other end measured and flattened. It is bent to shape and trimmed as necessary, then drilled to take the forward damper blade bolt.
It is a very simple installation. I have never seen
any indication of damage to the frame through their use unless the drill bit being nused is finito.
Brake Reaction Bars are made of a number from a number different metals
and formats and levels of sophistication these days. They can also be purchased
from Mulfa) or Heart of England Morgans (John
Worrall) or Librands. (See the Morgan
Masters Page.) There is also a write-up on making and fitting them
in Cuthbert Twillie's famous a Yank in Malvern. They can even be very effect
made from a flat metal strap.
Update July 2012: I have noticed that the Factory has copied the Mulberry design (again) and is now selling them in stainless through their dealership network. I have no reports as yet on the strength of their retaining bolts.
WATCHPOINT 2: One important precaution is to use bolts WEAK ENOUGH TO SHEAR IN AN IMPACT. The Mulfab and Heart of England versions are supplied with such bolts. The reason for this is key. It is a wonderful accident of the traditional Morgan design and wooden tub that they create crumple zones front and back...and this was before the vital need for crumple zones was even understood as they are now. An automobile crumple zone absorbs impact forces rather than passing them on to the occupants. The lack of them was why race drivers (and road drivers) used to die so often in the sad past.
We do not want the brake reaction bars to prejudice this important safety feature in any way. So the reaction bars fittings at the frame are carefully chosen to shear with an impact and allow the design to absorb forces rather than pass them on to you. But sadly, over the years new suppliers, less mechanically savvy forums and even the new MMC have copied brake reaction bars without fully understanding them or their effect on the car. Many of the lower fitting bolts I have seen of late are far too strong. We live in a world now where profits are a justification for ANYTHING. Do not play around with fatality merely trying steady your front end. Sadly, big bolts mean big bolt holes, so swapping in appropriate bolts might negate the ideal effect of these bars if you already have badly designed ones. My wife and I lived through what should have been a deadly accident which totally destroyed our Morgan. I received a survey from the subsequent professional investigation stating, unequivocally, that we would have died without the Morgan crumple zones. In an impact, I learned that lives hang on mere millimeters of metal. DO NOT let your proper enthusiasm for a better handling Morgan lead you astray. The proper bottom bolts will NOT prejudice the handling advantage of this addon and there is NO extra cost.
The first thing I noticed after installation was how much
better the steering felt in rough corners. The cracking of the wing
ceased (and was covered up by installation of wing mirrors over the top
of the existing cracks and bolted through the wing stay). I have since
installed them on every Morgan that Barbara and I have owned and several
others for friends. I think they are beneficial to all Morgans. I
have always installed them "to fit" and never made any attempt to adjust
caster through them. I am the most surprised that they only recently
(in the last several years) re-surfaced as a "new" innovation in England.