Front Brake Caliper Overhaul J55
- Replace all the components included in the repair kits used to
service this brake caliper.
- Lubricate the rubber parts with new Delco Supreme 11®
(GM P/N 12377967) or equivalent DOT-3 brake fluid to make assembly
easier.
- If any hydraulic component is removed or disconnected, it may
be necessary to bleed all or part of the brake system.
- The torque values specified are for dry, non-lubricated fasteners.
- Perform the service operations on a clean bench, free from all
mineral oil materials.
- Remove the brake caliper
from vehicle. Refer to
Front Brake Caliper Replacement
.
- Drain the brake fluid from the brake caliper.
Caution: Do not place your fingers in front of the piston in order
to catch or protect the piston while applying compressed air. This could result
in serious injury.
Notice: Use clean cloths to pad interior of caliper housing during piston removal.
Use just enough air to ease the pistons out of the bores. If the pistons are
blown out, even with the padding provided, it may be damaged.
- Place a 25 mm (1 in) block of wood between the caliper
and the piston.
- Install a large C-clamp over the body of the brake caliper with
the C-clamp ends against the rear of the caliper body and against the block
of wood.
- Carefully remove the brake caliper piston by directing low pressure
compressed air into the brake caliper inlet hole.
- Remove the C-clamp form the caliper.
- Remove the block of wood from the caliper.
- Install clean cloths to pad the interior of the caliper housing
between the remaining caliper piston and the caliper body.
- To cover the open caliper bore place a 25 mm (1 in)
block of wood between the caliper body and the brake caliper dust boot seal.
- Install a large C-clamp over the body of the brake caliper with
the C-clamp ends against the rear of the caliper body and against the block
of wood.
- Carefully remove the brake caliper piston by directing low pressure
compressed air into the brake caliper inlet hole.
- Remove the C-clamp form the caliper.
- Remove the block of wood from the caliper.
Important: Care must be used when removing the piston boot and seal from the caliper.
Use a small plastic or wood tool for removal. Do not use a metal tool because
it may damage the caliper bore or seal groove.
- Remove the piston boots from the brake caliper.
- Remove the piston seals from the brake caliper.
- Remove the brake caliper bleeder valve and cap from the brake
caliper.
Important: Do not use abrasives to clean the brake caliper piston.
- Clean the brake caliper piston bore and seal counterbore,
and the caliper piston with denatured alcohol, or equivalent.
- Dry the caliper piston bores and counterbores, and the piston
with non-lubricated, filtered air.
- Inspect all of the brake caliper parts as follows.
• | Piston - Inspect for scoring, nicks, cracks, wear, or corrosion.
Replace the pistons if any damage is found. |
• | Caliper Bore - Inspect for scoring, nicks, cracks, wear, or corrosion.
Use crocus cloth to polish out light corrosion. Otherwise, replace the caliper.
Do not hone the caliper bore. |
• | Seal groove in the caliper bore for nicks or burrs. If found,
replace the caliper. |
- Install the brake caliper bleeder valve and bleeder valve cap
into the brake caliper.
- Lubricate the new piston seal with Delco Supreme 11®
(GM P/N 12377967) or equivalent DOT-3 brake fluid from a clean,
sealed brake fluid container.
- Install the lubricated, new piston seals into the caliper bores.
- Using a caliper piston dust boot seal installer, or equivalent
tool, that will fully seat the dust boot seal for the seal counterbore diameter
and the piston bore diameter specified.
Specification
• | Brake caliper piston dust boot seal counterbore diameter 71.96 mm
(2.833 in). |
• | Brake caliper piston bore diameter 56.5 mm (2.224 in). |
- Install the brake caliper to the vehicle. Refer to
Front Brake Caliper Replacement
.
Front Brake Caliper Overhaul without J55
Tools Required
J 35777 Caliper Piston
Seal Installer
Caution: Refer to Brake Dust Caution in the Preface section.
Caution: Refer to Brake Fluid Irritant Caution in the Preface section.
Notice: Refer to Brake Fluid Effects on Paint and Electrical Components Notice in the Preface section.
- Remove the front brake caliper from the vehicle. Refer to
Front Brake Caliper Replacement
.
Caution: Do not place your fingers in front of the piston in order
to catch or protect the piston while applying compressed air. This could result
in serious injury.
Notice: Use clean cloths to pad interior of caliper housing during piston removal.
Use just enough air to ease the pistons out of the bores. If the pistons are
blown out, even with the padding provided, it may be damaged.
- Remove the brake caliper piston from the caliper bore by directing low pressure
compressed air into the caliper bore through the fluid inlet hole.
- Using
a small wooden or plastic tool, remove the piston dust boot seal (2) from
the seal counterbore in the caliper (1) and discard the boot seal.
- Using a small wooden or plastic tool, remove the piston seal (4)
from the caliper bore and discard the piston seal.
- Remove the bleeder valve (5) and cap (6) from the caliper (1).
Important: Do not use abrasives to clean the brake caliper
piston.
- Clean the brake caliper piston bore and seal counterbore, and the caliper
piston with denatured alcohol, or equivalent.
- Dry the caliper piston bore and counterbore, and the piston with non-lubricated,
filtered air.
- Inspect the caliper bore for cracks, scoring, pitting, excessive rust,
and/or excessive corrosion.
- If light rust or light corrosion are present in the caliper bore, attempt
to remove the imperfection with a fine emery paper. If the imperfection cannot be
removed, replace the caliper assembly.
- If cracks, scoring, pitting, excessive rust, and/or excessive corrosion
are present in the caliper bore, replace the caliper assembly.
- Inspect the caliper piston for cracks, scoring, and/or damage to the
chrome plating. Replace the caliper piston if any of these conditions exist.
- Lubricate the new piston seal with Delco Supreme 11®, GM P/N 12377967
(Canadian P/N 992667) or equivalent DOT-3 brake fluid from a
clean, sealed brake fluid container.
- Install the lubricated, new piston seal into the caliper bore.
- Install the caliper piston into the caliper bore.
- Install the new piston dust boot seal
over the piston.
- Using J 35777
fully
seat the dust boot in the caliper.
- Install the bleeder valve and cap to the caliper and tighten the valve
securely.
- Install the caliper to the vehicle. Refer to
Front Brake Caliper Replacement
.