Adjusting Vacuum brake?

[Tony Smith]

Originally Posted by Malcolm Towrie

Would it be correct to adjust the vacuum brake so it just contacts the disk at idle, which I can see by watching the timing light just start to retard? Because the vacuum at idle is up around 20", so at high loads, when the vacuum drops to near zero, the full spring tension will be braking the disk.

Malcolm

That's about the right spot. An important thing to check is the condition of the leather brake pad. If the leather has gone dry and hard, or worn, or has ANY kind of lube contamination it won't have the same hold on the breaker plate, likewise if the edge of the plate has any rust or roughness, it will bind on the brake pad and give you bad timing.