Harley Davidson 1986-2003 XL/XLH Sportster. Service Manual - page 40

CAUTION

Do not allow the pistons to travel out far
enough to contact the brake disc. If this hap-
pens, the pistons may damage the disc during
caliper removal.

b. Slowly apply the front brake lever to push the piston

part way out of the caliper for ease of removal during
caliper service.

3B. If caliper service is not required, insert a spacer be-
tween the brake pads (Figure 25) in the caliper. The spacer
prevents the piston from being forced out of the caliper if
the brake lever is squeezed while the caliper is removed
from the brake disc. If the pistons are forced out, disassem-
ble the caliper and reseat the pistons as described in this
chapter.

NOTE

If complete removal of the caliper is not nec-
essary, suspend the caliper and disregard the
remaining steps.Do not let the caliper hang
from the brake line.

4. Drain the brake fluid from the front brake hose as de-
scribed in

Brake Hose and Line Replacement

in this chap-

ter.
5. Remove the banjo bolt from the caliper (C, Figure 24).
Remove the bolt and the two washers. Place the open hose
end into a plastic bag to prevent spills and to keep out dirt.
6. Remove the caliper. Place it in a plastic bag until instal-
lation or disassembly.

Installation

WARNING

The upper and lower caliper bushings must
be installed in the fork slider prior to install-
ing the brake caliper. Otherwise, the caliper
and pad will be improperly located in relation
to the brake disc. This condition will bind the
caliper and brake pads, causing uneven brak-
ing and possible brake lockup.

1. Make sure the upper and lower caliper bushings, in-
stalled in the fork slider, are in place (Figure 26, typical).
2. If removed, install the brake pads as described in this
chapter.
3. Coat the lower mounting pin with high-temperature bear-
ing/brake grease (Dow Corning Moly 44 or equivalent).
4. Align the two mounting holes in the caliper with the fork
slider mounting lugs.
5. Install a washer onto the upper mounting screw and in-
sert the screw (A, Figure 24) through the slider lug and
then thread into the caliper bushing. Install the screw fin-
ger-tight.
6. Insert the lower mounting pin (B, Figure 24) through
the caliper and thread it into the slider lug. Tighten the
mounting screw finger-tight.

BRAKES

541

7. Tighten the lower mounting pin (B, Figure 24) to 25-30
ft.-lb. (34-41 N•m)
8. Tighten the upper mounting screw (A, Figure 24) to
25-30 ft-lb. (34-41 N•m)..
9. Tighten the bleed valve (D, Figure 24) to 80-100 in.-lb.
(9-11 N•m).
10. If removed, assemble the brake line onto the caliper by
placing a

new

washer (Figure 27) on both sides of the brake

line fitting, then secure the fitting to the caliper with the
banjo bolt (C, Figure 24). Tighten the banjo bolt to 17-22
ft.-lb. (23-30 N•m). Orient the fitting against the caliper as
shown in C, Figure 24.
11. If necessary, refill the system and bleed the brakes as
described in this chapter.
12. While the motorcycle is stationary with the engine off,
squeeze the front brake lever several times to seat the pads
against the disc.

WARNING

Do not ride the motorcycle until the brakes
operate properly.

Disassembly

Refer to Figure 28.

1. Partially remove the piston form the caliper as described
during caliper removal in this section.

WARNING

Compressed air will force the piston out of the
caliper under considerable force. Do not
block the piston by hand as injury will occur.

2. Insert a small screwdriver into the notched groove ma-
chined in the bottom of the piston bore (Figure 29). Then
pry the retaining ring (Figure 30) out of the caliper body.
3. If the piston did not come partially out of the caliper
bore, perform the following:

a. Place a rag and a wood block in the caliper (Figure

31). Keep fingers out of the way of the piston.

b. Apply compressed air through the brake hose port

and force the piston out of the caliper.

4. Remove the piston and dust boot assembly (Figure 32).
5. Remove the piston seal (Figure 33) from the groove in
the caliper body.
6. Pull the threaded bushing (A, Figure 34) out of the cali-
per, then remove the pin boot (B).
7. Remove the O-rings from the caliper body (Figure 35).

Inspection

Service specifications for the front caliper components

are not available from the manufacturer. Replace worn,
damaged or questionable parts.
1. Clean the caliper body and piston in new DOT 5 brake
fluid or isopropyi alcohol, and dry them with compressed air.

2. Make sure the fluid passageway in the base of the piston
bore is clear. Apply compressed air to the opening to make
sure it is clear. Clean it out, if necessary, with new brake fluid.
3. Inspect the piston seal groove in the caliper body for
damage. If it is damaged or corroded, replace the caliper as-
sembly.
4. Inspect the banjo bolt threaded hole in the caliper body.
If it is worn or damaged, renew it using an appropriately
sized thread tap or replace the caliper assembly.
5. Inspect the bleed valve threaded hole in the caliper body.
If it is worn or damaged, renew it using an appropriately
sized thread tap or replace the caliper assembly.
6. Inspect the bleed valve. Apply compressed air to the
opening and make sure it is clear. Clean it out with new
brake fluid. Install the bleed valve and tighten it to 80-100
in.-lb. (9-10 N•m).
7. Inspect the caliper body for damage.
8. Inspect the cylinder wall and piston (Figure 36) for
scratches, scoring or other damage.

Assembly

1. An original equipment rebuild kit includes a piston seal
(A, Figure 37), piston (B), dust boot (C) and retaining ring
(D).

WARNING

Never reuse an old dust boot or piston seal.
Very minor damage or age deterioration can
result in leaks and possible brake failure.

2. Soak the new dust and piston seal in clean DOT 5 brake
fluid.
3. Install the new piston seal into the groove. Make sure the
seal is properly seated in its groove.
4. Install new O-rings into the caliper grooves.
5. Wipe the inside of the pin boot with high-temperature
bearing/brake grease (Dow Corning Moly 44 or equiva-
lent). Then insert the boot into the bushing bore with the
flange end seating in the bore groove (Figure 38).
6. Insert the threaded bushing into the boot (Figure 39).
7. Install the piston dust boot on the piston before the pis-
ton is installed in the caliper bore. Perform the following:

542

CHAPTER SIXTEEN

BRAKES

543

FRONT BRAKE CALIPER

(1986-1999 MODELS)

1. Screw
2. Pad retainer
3. Inner brake pad
4. Outer brake pad
5. Retaining ring
6. Dust boot
7. Piston
8. Piston seal
9. O-rings

10. Spring clip

11. Caliper body
12. Bleed valve
13. Washer
14. Upper mounting screw
15. Lower mounting pin

16A. Threaded bushing (1986-1991 models)
16B. Threaded bushing (1992-1999 models)

17. Pin boot

18A. Pad holder (1986-1991 models)
18B. Pad holder (1992-1999 models)

a. Place the piston on the workbench with its open side

facing up.

b. Align the piston dust boot with the piston so the

shoulder on the dust boot faces up.

c. Slide the piston dust boot onto the piston until the in-

ner lip on the dust boot seats in the piston groove
(Figure 32).

8. Coat the piston and the caliper bore with DOT 5 brake
fluid.
9. Align the piston with the caliper bore so its open end
faces out (Figure 32). Push the piston into the bore until it
bottoms.
10. Seat the piston dust boot (Figure 40) into the caliper
bore.
11. Locate the retaining ring groove in the top end of the
caliper bore. Align the retaining ring so its gap (Figure 41)
is at the top of the caliper bore and install the ring into the
ring groove. Make sure the retaining ring is correctly seated
in the groove.
12. Apply a light coat of high-temperature bearing/brake
grease (Dow Corning Moly 44 or equivalent) to the caliper
mounting lug bores.
13. If the bleed valve was removed, install it and tighten it
to 80-100 in.-lb. (9-11 N•m).
14. Install the caliper and brake pads as described in this
section.
15. Bleed the brakes as described in

Bleeding the System

this chapter.

544

CHAPTER SIXTEEN

Wood block

Rag

Air nozzle

FRONT BRAKE CALIPER

(2000-2003 MODELS)

Review

Brake Service

in this chapter.

Removal

1. If the caliper is going to be disassembled for service,
perform the following:

NOTE

If the brake pads will be reused, mark each
pad so it can be reinstalled in its original po-
sition in the caliper.

a. Remove the brake pads as described in this chapter.

CAUTION

Do not allow the pistons to travel out far
enough to contact the brake disc. If this hap-
pens, the pistons may damage the disc during
caliper removal.

b. Slowly apply the brake lever to push the pistons part

way out of the caliper assembly for ease of removal
during caliper service.

c. Loosen the two body mounting bolts (A, Figure 42).
d. Loosen the brake hose banjo bolt (B, Figure 42).

2. Remove the banjo bolt and sealing washers (B, Figure
42). Account for the sealing washer on each side of the hose
fitting(s).

BRAKES

545

Align gap with top of caliper bore

Retaining
ring

3. Place the loose end of the brake hose in a plastic bag to
prevent the entry of debris and keep brake fluid from leak-
ing out.
4. Remove the mounting bolts (Figure 43).
5. Remove the caliper. Place it in a plastic bag until instal-
lation or disassembly.

Installation

1. Install the caliper assembly onto the disc, take care not
to damage the leading edge of the brake pads.
2. Install the mounting bolts (Figure 43). Install the long
bolt into the upper hole. Install the upper bolt finger-tight,
then install the lower bolt. Tighten the lower bolt to 28-38
ft.-lb. (38-52 N•m). Tighten the upper bolt to 28-38 ft.-lb.
(38-52 N•m).
3. Apply new DOT 5 brake fluid to the rubber portions of
the new banjo bolt sealing washers prior to installation.
4. Install a new sealing washer on each side of the brake
hose fitting and install the banjo bolt (B, Figure 42).
Tighten the banjo bolt to 17-22 ft.-lb. (23-30 N•m).
5. Bleed the brake as described in this chapter.

Disassembly

Refer to Figure 44.

1. Remove the caliper as described in this section.
2. Remove the two caliper body bolts (Figure 45) loos-
ened during the removal procedure.
3. Separate the caliper body halves. Remove the O-rings
(Figure 46). New O-rings must be installed every time the
caliper is disassembled.

NOTE

If the pistons were partially forced out of the
caliper body during removal, steps 4-6 may
not be necessary. If the pistons or caliper
bores are corroded or very dirty, compressed
air may be necessary to completely remove
the pistons from the body bores.

4. Place a piece of soft wood and a shop cloth over the end
of the pistons and the caliper body. Turn this assembly over
with the pistons facing down on top of a workbench.

WARNING

Compressed air forces the pistons out of the
caliper body under considerable force. Do not
block the piston by hand, as injury will result.

5. Apply the air pressure in short spurts to the hydraulic
fluid passageway and force out the pistons. Repeat for the
other caliper body half.

CAUTION

Do not use a sharp tool to remove the dust
and piston seals from the caliper cylinders.
Do not damage the cylinder surface.

6. Use a piece of wood or a plastic scraper and push the
dust seal and the piston seal (Figure 47) in toward the cali-
per cylinder and out of their grooves. Remove the dust and
piston seals.
7. If necessary, unscrew and remove the bleed valve (A,
Figure 48).
8. Inspect the caliper as described in this section.

Inspection

1. Clean both caliper body halves and pistons in new DOT
5 brake fluid or isopropyl alcohol and dry with compressed
air.
2. Make sure the fluid passageways (Figure 49) in the pis-
ton bores are clear. Apply compressed air to the openings to
make sure they are clear. Flush the passageways, if neces-
sary, with new brake fluid.
3. Make sure the fluid passageways (A, Figure 50) in both
caliper body halves are clear. Apply compressed air to the
openings to make sure they are clear. Flush the passage-
ways, if necessary, with new brake fluid.
4. Inspect the piston and dust seal grooves (Figure 51) in
both caliper bodies for damage. If damaged or corroded, re-
place the caliper assembly.
5. Inspect the banjo bolt threaded hole (B, Figure 48) in
the outboard caliper body. If worn or damaged, renew with
an appropriately sized thread tap or replace the caliper
assembly.
6. Inspect the bleed valve threaded hole in the caliper body.
If worn or damaged, clean out with an appropriately sized
thread tap or replace the caliper body.
7. Inspect the bleed valves (A, Figure 48). Apply com-
pressed air to the opening and make sure it is clear. Clean
out, if necessary, with clean brake fluid. Install the bleed
valve and tighten to 80-100 in.-lb. (9.0-11.3 N•m).
8. Inspect both caliper body halves for damage. Check the
inboard caliper mounting bolt hole threads (B, Figure 50)
for wear or damage. Clean up the threads with an appropri-
ately sized tap or replace the caliper assembly.
9. Inspect the cylinder walls and pistons for scratches,
scoring or other damage.

546

CHAPTER SIXTEEN

BRAKES

547

FRONT BRAKE CALIPER (2000-2003 MODELS)

1. Inboard caliper

body

2. Crossover O-ring
3. Piston seal
4. Dust seal
5. Piston
6. Anti-rattle spring
7. Brake pad
8. Outboard caliper

body

9. Bridge bolt

10. Bleed valve
11. Pad pin

10. Check the anti-rattle spring (Figure 52) for wear or
damage.

Assembly

CAUTION

Never reuse old dust seals or piston seals.
Very minor damage or age deterioration can
result in leaks and possible brake failure.

1. Soak the new dust and piston seals in new DOT 5 brake
fluid.
2. Coat the piston bores and pistons with new DOT 5 brake
fluid.
3. Install the new piston seals into the lower grooves. Make
sure the seals are properly seated in their respective
grooves.
4. Install the new dust seals into the upper grooves. Make
sure all seals are properly seated in their respective grooves
(Figure 53).
5. Repeat Step 3 and Step 4 for the other caliper body half.
6. Position the pistons with the open end facing out and in-
stall the pistons into the caliper cylinders (A, Figure 54).
Push the pistons into the bore until they bottom (B).
7. Repeat Step 6 for the other caliper body half. Make sure
all pistons are installed correctly.
8. Coat the new O-ring seals in new DOT 5 brake fluid and
install the O-rings (Figure 46) into the inboard caliper half.
9. Install the anti-rattle spring (Figure 55) onto the boss on
the outboard caliper half.
10. Make sure the O-rings are still in place and assemble
the caliper body halves.
11. Install one of the caliper mounting bolts through the
upper hole (A, Figure 56) to correctly align the caliper
halves.
12. Install the two caliper body bolts (B, Figure 56) and
tighten securely. They will be tightened to the specified
torque after the caliper is installed on the front fork.
13. If removed, install the bleed valve assembly and
tighten to 80-100 in.-lb. (9.0-11.3 N•m).
14. Install the caliper as described in this section.

FRONT MASTER CYLINDER

(1986-1995 MODELS)

Review

Brake Service

in this chapter.

Refer to Figure 57.

Removal

1. Pull the rubber cover off of the front caliper bleed valve
(Figure 58) and insert a hose onto the end of the valve. In-
sert the open end of the hose into a container. Open the front
bleed valve and drain the brake fluid from the front brake
assembly by operating the hand lever. Remove the hose and
close the bleed valve after draining the assembly. Discard

548

CHAPTER SIXTEEN

the brake fluid. Refer to

Brake Fluid Draining

in this chap-

ter.
2. Place a couple of shop cloths under the banjo bolt and
remove the banjo bolt and washers securing the brake hose
to the master cylinder (A, Figure 59).
3. Remove the screws (B, Figure 59) securing the master
cylinder to the handlebar and remove the master cylinder.

Installation

1. Position the master cylinder onto the handlebar and in-
stall the clamp and screws (B, Figure 59). Tighten the
screws to 70-80 in.-lb. (8-9 N•m).
2. Install the brake hose onto the master cylinder and brake
caliper. Be sure to place a

new

banjo bolt washer on each

side of the hose fitting (A, Figure 59) when installing the
banjo bolt. Tighten the banjo bolt to 17-22 ft.-lb. (23-30
N•m).
3. Fill the master cylinder with new DOT 5 brake fluid.
Bleed the brake system as described in this chapter.
4. If necessary, loosen the clamp screws and reposition the
master cylinder to suit the rider. Retighten the clamp screws
to 70-80 in.-lb. (8-9 N•m).

Disassembly

1. Remove the master cylinder as described in this section.
2. If still in place, remove the screws securing the top cover
and remove the cover and diaphragm.
3. Remove the brake lever assembly as follows:

a. Remove the snap ring from the pivot pin.
b. Push out the pivot pin and remove the brake lever as-

sembly.

c. Remove the reaction pin (A, Figure 60) from the

brake lever (B).

d. Remove the pushrod from the piston assembly.

4. Remove the piston assembly as follows:

a. Remove the dust boot (A, Figure 61).
b. Remove the piston and spring assembly (B, Figure

61).

5. If damaged, remove the grommet and sight glass from
the master cylinder housing.

Assembly

1A. If installing the original equipment master cylinder re-
build kit, use the supplied lubricant to coat the master cylin-
der bore and piston components.
1B. If installing an aftermarket master cylinder rebuild kit,
soak the piston O-ring and cup in new DOT 5 brake fluid
prior to installation. Apply a thin coat of brake fluid to the
cylinder bore prior to assembly.
2. Install the grommet and sight glass if removed.
3. Install the cup onto the small end of the spring.
4. Install the O-ring onto the piston.

BRAKES

549

550

CHAPTER SIXTEEN

FRONT MASTER CYLINDER (1986-1995 MODELS)

1. Screw
2. Cover
3. Diaphragm
4. Sight glass
5. Grommet
6. Reservoir/body
7. Sealing washers
8. Brake hose
9. Banjo bolt

10. Screw
11. Clamp

12. Pivot pin
13. Brake lever
14. Snap ring
15. Spring
16. Cup
17. Piston
18. O-ring
19. Dust boot
20. Pushrod and brake

switch

21. Reaction pin

4. Position the spring with the wide end first and install the
spring into the master cylinder.

5. Position the piston with the O-ring end going in last and
install the piston into the master cylinder (Figure 62).

6. Slide the dust boot (A, Figure 63) onto the pushrod (B).
Refer to Figure 64.

7. Assemble the brake lever as follows:

NOTE

Do not seat the dust boot into the master cyl-
inder at this time.

a. Slide the long end of the pushrod (Figure 65) into the

piston with the dust boot facing the piston. Turn the
pushrod so the arm faces the master cylinder.

b. Apply a light coat of antiseize lubricant onto the reac-

tion pin (A, Figure 66).

c. Install the reaction pin (A, Figure 66) into the brake

lever (B). Make sure the square pinhole (Figure 67)
faces out.

d. Slide the brake lever into the master cylinder and seat

the end of the pushrod into the reaction pin hose (Fig-
ure 68). Hold the brake lever in this position. Install
the pushrod arm into the cutout in the master cylinder.

e. Slide the pivot pin though the master cylinder and

brake lever pivot holes.

BRAKES

551

f. Turn the master cylinder over and install the snap ring

into the pivot pin groove. Make sure the snap ring is
seated correctly in the groove.

g. Apply the brake lever once to seat the dust seal into

the master cylinder bore (Figure 69).

8. Apply the brake lever several times. There must be no
binding or excessive play. Make sure the pushrod is seated
in the reaction pinhole (Figure 69). If the brake lever does
not operate correctly, repeat this procedure and correct the
problem.

WARNING

If the assembled pushrod and reaction pin are
not operating correctly, the front master may
cause the front brake to lock up and/or result
in the complete loss of front brake operation.

Inspection

Replace worn or damaged parts as described in this sec-

tion. A new piston kit should be installed every time the
master cylinder is disassembled.

1. Clean all parts in new DOT 5 brake fluid or isopropyi
alcohol. Inspect the body cylinder bore surface for signs of
wear and damage. If it is less than perfect, replace the mas-
ter cylinder assembly. The body cannot be replaced sepa-
rately.

2. The piston assembly consists of the dust boot, O-ring,
piston, cup and spring. Inspect the rubber parts for wear,
cracks, swelling or other damage. Check the piston for wear
or damage. If any one part of the piston assembly is dam-
aged, replace the entire piston assembly as a kit.

3. Inspect the master cylinder bore for scratches or wear
grooves.

4. Clean the vent hole in the cover if plugged.

5. Check the banjo bolt threads in the master cylinder. If
the threads are slightly damaged, renew them using the
properly sized thread tap. If the threads are severely worn
or damaged, replace the master cylinder body.

6. Inspect the piston bore in the master cylinder for wear,
corrosion or damage. Replace the master cylinder if
necessary.

NOTE

If a tap is used to clean the threads in the mas-
ter cylinder, flush the master cylinder thor-
oughly and blow dry.

7. Make sure the banjo bolt passage hole is clear.

FRONT MASTER CYLINDER

(1996-2003 MODELS)

Review

Brake Service

in this chapter.

Refer to Figure 70.

552

CHAPTER SIXTEEN

Identification

Two different master cylinders are used depending on the

number of front disc brakes on the motorcycle. The master
cylinder used with a single front brake disc has a smaller bore
than the master cylinder used with dual brake discs.

A number cast into the master cylinder body (Figure 71)

identifies the type of master cylinder. The number “9/16”
identifies a master cylinder designed for single-disc operation.

The number “11/16” identifies a master cylinder designed for
dual-disc operation.

Removal

1. Pull the rubber cover off the front caliper bleed valve
(Figure 72) and insert a hose onto the end of the valve. Insert
the open end of the hose into a container. Open the front

BRAKES

553

FRONT MASTER CYLINDER (1996-2003 MODELS)

1. Site glass
2. Screw
3. Cover
4. Diaphragm
5. Washer
6. Brake line
7. Banjo bolt
8. Pivot pin
9. Bushing

10. Lever
11. Snap ring
12. Reservoir/body
13. Clamp
14. Washer
15. Spring
16. Primary cup
17. Piston
18. O-ring
19. Piston cap
20. Wiper

Single-disk models

1200S models

bleed valve and drain the brake fluid from the front brake as-
sembly by operating the hand lever. Remove the hose and
close the bleed valve after draining the assembly. Discard the
brake fluid. Refer to

Brake Fluid Draining

in this chapter.

2. Clean the top of the master cylinder.

CAUTION

Failure to install the spacer in Step 3 will re-
sults in damage to the rubber boot and
plunger on the front brake switch.

3. Insert a 5/32 in. (4 mm) thick spacer (A, Figure 73) be-
tween the brake lever and lever bracket. Make sure the
spacer stays in place during the following steps.
4. Remove the banjo bolt (A, Figure 74) and sealing wash-
ers securing the brake hose to the master cylinder.
5. Place the loose end of the brake hose in a plastic bag to
prevent fluid leaks and the entry of moisture and debris.
6. Remove the screw securing the right side handlebar
switch together and separate the switch.
7. Remove the bolts and washers securing the clamp and
master cylinder to the handlebar.
8. Remove the master cylinder assembly from the handle-
bar.
9. If necessary, remove the screws (B, Figure 74) securing
the cover, then remove the cover (C) and diaphragm. Drain
any residual brake fluid from the master cylinder and dis-
pose of it properly.
10. If the master cylinder assembly is not going to be ser-
viced, reinstall the clamp and bolts to the master cylinder.
Place the assembly in a plastic bag to protect it from mois-
ture and debris.

Installation

CAUTION

Failure to install the spacer between the
brake lever and the brake spacer results in
damage to the rubber boot and plunger on the
front brake switch.

1. Insert the 5/32 in. (4 mm) thick spacer between the brake
lever and lever bracket if not in place. Make sure the spacer
stays in place during the following steps.
2. Position the front master cylinder onto the handlebar.
Align the master cylinder notch (B, Figure 73) with the lo-
cating tab on the lower portion of the right side switch.

CAUTION

Do not damage the front brake light switch
and rubber boot (

Figure 75

, typical) when in-

stalling the master cylinder.

3. Push the master cylinder all the way onto the handlebar
(A, Figure 76). Hold it in this position and install the upper
portion of the right side switch (B, Figure 76). Install the
switch clamp screw and tighten it securely.

554

CHAPTER SIXTEEN

4. Position the clamp and install the bolts and washers.
Tighten the upper mounting screw, then the lower screw.
Tighten the screws to 70-80 in.-lb (8-9 N•m).
5. Apply new DOT 5 brake fluid to the rubber portions of
the new sealing washers prior to installation.
6. Install new sealing washers and the banjo bolt (Figure
77) securing the brake hose to the master cylinder (A, Fig-
ure 74). Tighten the banjo bolt to 17-22 ft.-lb. (23-30 N•m).
7. Remove the spacer from the brake lever.
8. Refill the master cylinder reservoir and bleed the brake
system as described in this chapter.

Disassembly

1. Remove the master cylinder as described in this sec-
tion.
2. If still in place, remove the top cover and diaphragm.
3. Remove the snap ring (A, Figure 78) and pivot pin se-
curing the hand lever to the master cylinder. Remove the
hand lever (B, Figure 78).
4. Remove the retainer (A, Figure 79) and the rubber boot
(B) from the area where the hand lever actuates the piston
assembly.
5. Remove the piston assembly (Figure 80) and the
spring.
6. Inspect all parts as described in this section.

Inspection

Replace worn or damage parts as described in this sec-

tion. Install a new piston kit assembly every time the master
cylinder is disassembled.
1. Clean all parts in new DOT 5 brake fluid or isopropyl al-
cohol. Inspect the body cylinder bore surface for signs of
wear and damage. Replace the master cylinder assembly, if
damaged. The body cannot be replaced separately.
2. Inspect the piston cup (A, Figure 81) and O-ring (B) for
signs of wear and damage.
3. Make sure the fluid passage (Figure 82) in the bottom of
the master cylinder reservoir is clear. Clean it out if neces-
sary.

BRAKES

555

4. Inspect the piston contact surface for signs of wear and
damage.
5. Check the end of the piston (C, Figure 81) for wear
caused by the hand lever.
6. Check the hand lever pivot lugs in the master cylinder
body for cracks or elongation.
7. Inspect the hand lever pivot hole and bushing (A, Fig-
ure 83), and the pivot pin (B) for wear, cracks or elonga-
tion.
8. Inspect the piston cap and retainer (Figure 84) for wear
or damage.
9. Inspect the threads in the bore for the banjo bolt. If they
are worn or damaged, clean them out with a thread tap or re-
place the master cylinder assembly.
10. Check the top cover and diaphragm for damage or de-
terioration.
11. If necessary, separate the cover from the diaphragm as
follows:

a. Pull straight up on the sight glass (Figure 85) and re-

move it from the cover and diaphragm.

b. Separate the diaphragm from the cover.
c. The trim plate may separate from the cover.

Assembly

CAUTION

The cover and diaphragm must be assembled
as described. If the sight glass is not installed
correctly through the cover and diaphragm
neck, brake fluid will leak past these compo-
nents.

Refer to Figure 71.

1A. If installing the original equiment master cylinder re-
build kit, use the supplied lubricant to coat the master cylin-
der bore and piston components.
1B. If installing an aftermarket master cylinder rebuild kit,
soak the piston O-ring in new DOT 5 brake fluid prior to in-
stallation. Apply a thin coat of brake fluid to the cylinder
bore assembly.
2. If the cover and the diaphragm were disassembled, as-
semble them as follows:

a. Install the trim plate (Figure 86) onto the cover if it

was removed.

b. Insert the neck of the diaphragm into the cover. Press

it in until it seats correctly and the outer edges align
with the cover.

c. Push the sight glass (Figure 85) straight down

through the cover and the neck of the diaphragm
(Figure 87) until it snaps into place. The sight glass
must lock these two parts together to avoid leaks.

3. Soak the new cup, O-ring and piston assembly in new
DOT 5 brake fluid for 15 minutes to make them pliable.
Coat the inside of the cylinder bore with new brake fluid
prior to the assembly of parts.

556

CHAPTER SIXTEEN

Content .. 38 39 40 41 ..