SUB-SECTION 9D
BRAKE CHAMBERS
3. The power spring should be wire brushed and imme-
diately coated with-a rust inhibiting compound, It is im-
portant that all rust on the inside diameter of the spring be
removed.
4. The spring support should be wire brushed and coated
with rust inhibiting compound.
5. Inspect the push rod for a loose pressure plate and rod
wear. If rust is present, wire brush and coat with rust in-
hibiting compound.
6. If the push rod return spring is rusty, it should be wire
brushed and coated with a rust inhibiting compound.
Figure 9D-10. Removing Piston Assembly
7. The remaining parts should be inspected in accordance
with standard brake service and shop practices.
12. Remove the O-ring and nylon bushing from the cylin-
der center boss. Use a sharp pointed instrument to remove
the bushing; work clockwise from the cut to pry the
REASSEMBLY. Reassemble the Maxibrake chamber as
bushing out of the groove (see Figure 9D-11).
follows:
1. Fill the inside center boss groove, and lightly coat the
cylinder bore, with grease. Install the small O-ring in the
inner center boss groove. Then install the nylon bushing in
the outer center boss groove with the beveled edge of the
bushing toward the inside of the cylinder (see Figure
9D-12).
2. Install the large O-ring in the piston groove nearest the
neck. Install the saturated felt wiper ring in the remaining
groove.
Figure 9D-11. Removing Nylon Bushing
INSPECTION AND REPAIR. After the Maxibrake chamber
has been disassembled, wash all the metal parts in cleaning
solvent and inspect and repair the following:
1. Check the bore diameter of the cylinder for rust,
scoring, or dents. Sandblasting of the cylinder removes the
plating and is not recommended. Inspect a cylinder with a
suitable bore finish for other defects, such as damaged or
worn studs and push rod bushing wear.
2. Remove all nicks and scratches from the piston skirt.
Figure 9D-12., Installing Nylon Bushing
The piston. neck is chrome plated, and only pistons with
necks in good condition should be reused. If the piston
3. Insert the piston assembly all the way into the cylinder,
neck is corroded, scored, or notched, corrective action
holding the felt wiper ring in place as the piston is inserted
should be taken to prevent a reoccurance. Painting the out-
(see Figure 9D-13).
side diameter of the piston neck must be avoided.
9D-7
