"There has been much discussion on the usefulness of the brake servos. Do you know why the servos were discontinued and do you have any opinion of their effectiveness?"
WATCHPOINT: These early Girling servos are unrelated to the later POWERSTOP servos used on all Classic Morgans after June 1993.
Secondly, what is the procedure and advantages of converting early Morgans from front drum brakes to front disc brakes?
The brake servos were very effective; I believe they may have been discontinued because of European legislation requiring a mechanical linkage between the servo and the brake pedal.
On a conversion from front drums to discs, the procedure is to use current 4/4 disc brakes which will require caliper brackets and in some cases new stub axles. The advantages are overwhelming for a car used other than a show car - greatly improved stopping distance and considerably more control under braking (i.e. the elimination of brake "pull" to one side or another).
I think the early Brake Servos were discontinued due to lack of supply (they became an obsolete part due to modern vehicles using a Brake servo/Master cylinder unit as per current Morgans). They were effective but there are now major parts availability problems for the old units.
To convert drum brake cars to discs you need new hubs, carrier bolts, the discs, the calipers, caliper carriers, bolts, flexible brake hoses, and, of course, brake Pads. The advantage is BETTER STOPPING POWER!
|WATCHPOINT by Derek Willburn on the Morgan Experience.
There are two problems with using your original front spindles:
1. The arms with tie rod connected will hit the rotors for caliper brakes. The later spindles have longer arms. If you are on a budget, the arms can be heated and bent inwards a bit to clear. The tie rod might need shortening.
2. The threads on the spindles are BSF threads and were not meant for taper bearing adjustment. The later spindles have a finer thread. You can use them but it is not ideal.
In changing to later spindles you have the choice of keeping it 5/8” dia on the spindle thread or going for the bigger 3/4” dia. This choice also affects the front hubs and bearings you need.
3. More parts you need are the spacer blocks for the two damper blades so they clear the brake
calipers. The spacer blocks on the chassis are removed and replaced by two flat plates to sandwich the blades.
4. Note: that the rubber brake lines will be moved to the valance panels just above the damper blade. You can put 3/8” bolts through the chassis where the olde lines mounted.
5. Another thing. If you have the original drag link, I recommend updating that to the later style that matches your tie rod.