Posted by Vaughn on June 04, 2000 at 17:09:45:
In Reply to: 51 m37 replacement of rear brake cylinder, help posted by rob on June 04, 2000 at 10:49:31:
Once you have your wheel, hub and brake shoes are off, take the boots, pistons, and cups out of the cylinder so you can see inside. If you have no deep pitting or scratches in the walls, then hone and put in new parts. Most of the time deep pitting results from these trucks sitting around for long periods without use. You can buy a new cylinder from A.B. Lynn or Vintage Power Wagons.
Instructions for Honing:
1. Hone the cylinder until no pits or scratches are left running parallel to the wheel cylinder
2. Was the cylinder with warm soap and water and dry the cylinder walls quickly. Dish detergent works well. This is the only way you will get all the hone grit out.
3. On assembly, lube the cylinder walls and new parts with brake fluid
4. Reassemble the brake shoes and wheel and nub to the spindle. Tighten the inner wheel bearing nut until snug and back off 1/6th (start at one hub stud and turn the nut back to the next stud)
Brake Shoe ADJUSTMENT
To adjust the brake shoe cams the following steps should be taken with wheel off the ground:
1. On the brake plate there are two ¾ inch nuts upper area, one on each side. Turn the front (front side of axle) brake shoe cam adjusting nut out (counter clockwise when facing wheel (driver side), or clockwise when facing brake plate) until wheel is locked, then back off until the wheel will spin;
2. Turn the cam for the rear shoe out (clockwise when facing wheel or counter clockwise when facing brake plate) until wheel is locked, then back off until wheel will spin;
3. Reverse for passenger side;
4. When bleeding start with rear passenger side wheel, then rear driver side, then front passenger then front driver side as final. Repeat until air is out, BUT MAKE SURE YOUR ARE CHECKING MASTER CYLINDER FLUID LEVEL FREQUENTLY DURING PROCESS to avoid pumping air into brake system;
5. Adjust brakes, then bleed!