GPierce
Well-known member
A friend of mine and I trying to sort out a brake bleeding problem. His customer brought him a 31 A with a brake conversion using 39 to 42 backing plates. As near as we can determine it has never worked right. He bought the A with the conversion all ready on it. All indications are there is air in the system. Blocking off the rear brake line the front brakes work. Blocking off the rear line we have no brakes and the pedal goes all the way to the floor. Bleeding the rear brakes yields no air or bubbles, just fluid.
Investigation shows the wheel cylinders are mounted on the bottom of the backing plates so the shock levers clear; backing plates turned upside down. This causes the fluid to come into the bottom of the cylinder with bleeder port above. It is our opinion that this results in air being trapped in the top of the cylinder and bleeding won't remove it. See attached picture with orientation the same as the mounted on the backing plate. You can see the bleed port on the bottom of the cylinder with fluid supply port above it.
How do those of you use tghe 39 to 42 backing plates solve this probllem?
Investigation shows the wheel cylinders are mounted on the bottom of the backing plates so the shock levers clear; backing plates turned upside down. This causes the fluid to come into the bottom of the cylinder with bleeder port above. It is our opinion that this results in air being trapped in the top of the cylinder and bleeding won't remove it. See attached picture with orientation the same as the mounted on the backing plate. You can see the bleed port on the bottom of the cylinder with fluid supply port above it.
How do those of you use tghe 39 to 42 backing plates solve this probllem?
