REMOVE AND INSTALL

1. Remove brake drums and shoes as outlined under DRUM AND BRAKE ASSEMBLIES, REMOVE.
2. Front wheel cylinder:
   1. Remove brake line from brake hose.
   2. Remove the brake hose retainer clip at the frame bracket.
   3. Remove brake hose from wheel cylinder.
3. Rear wheel cylinder - remove the brake line from the wheel cylinder.
4. Remove the wheel cylinder to backing plate attaching bolts and remove wheel cylinder.

To install, reverse the removal procedure, torque wheel cylinder to backing plate bolts 8 to 16 ft. lbs. and bleed the lines. (See BLEEDING OF LINES).

30, 31, 32 & 33 Series

DISASSEMBLY

The internal wheel cylinder boots, used on the 30, 31, 32 and 33 series. should be disassembled only when they are visibly damaged or leaking fluid.

Wheel cylinders having torn, cut, or heat cracked boots should be completely overhauled.

Inspection for leakage may be accomplished at the boot center hose after removal of the link pin. Fluid coatings on the piston within the cylinder and on the end of the link pin are normal, as the cylinder contains a porous Durex piston which is impregnated with a corrosion inhibiting fluid. Fluid spilling from the boot center hole, after the link pin is removed, indicates cup leakage and the necessity of completely overhauling the cylinder.

1. Pull boots from cylinder ends with pliers and discard boots.
2. Remove and discard pistons and cups.

CLEANING AND INSPECTION

1. Inspect cylinder bore. Check for staining or corrosion. It is best to discard a corroded cylinder.
2. Polish any discolored or stained area with crocus cloth by revolving the cylinder on the cloth supported by a finger. Do not slide the cloth in a lengthwise manner under pressure. Do not use any other form of abrasive or abrasive cloth.
3. Rinse the cylinder in Declene or brake fluid.
4. Shake excess cleaning fluid from the cylinder. Do not use a rag to dry the cylinder as lint from the rag cannot be kept from the cylinder bore surfaces.

NOTE

Staining is not to be confused with corrosion. Corrosion can be identified as pits or excessive bore roughness.

ASSEMBLY

1. Lubricate the cylinder bore and counterbore with brake fluid and insert spring-expander assembly.
2. Install new cups. (Be sure cups are lint and dirt free.) Do not lubricate cups prior to assembly..
3. Install new Durex pistons as they are received in the parts package. Do not lubricate pistons with brake fluid.
4. Press new boots into cylinder counterbores by hand. Do not lubricate boots prior to assembly.

 

34, 35, 36, 38 & 39 Series

DISASSEMBLY

1. Remove links and rubber boots.
2. Remove pistons, cups, expanders and spring from wheel cylinder bore.

CLEANING AND INSPECTION

1. Wash all metal parts in brake flushing fluid and blow out all passages with compressed air.
2. Inspect cups for a swelling or distorted condition, replace if damaged. If a swelling condition exists, the entire hydraulic system should be flushed (see FLUSHING HYDRAULIC SYSTEM) and all the rubber parts in the hydraulic system should be replaced.
3. Inspect the wheel cylinder bore for scores, rust, pits or etches. If any such conditions exist, the complete wheel cylinder will have to be replaced as an assembly.

CAUTION

Do not attempt to recondition a wheel cylinder bore as a means of salvaging the cylinder. Reconditions of the bore leaves the walls sufficiently rough to cause premature failure of the rubber cups. It also enlarges the bore to the extent that the standard size pistons and seals will not fit properly.

ASSEMBLY

Lubricate the bore of the wheel cylinder and all rubber parts with Brake Fluid Super No. 11 and assemble as shown in Fig. 11-14.