Chapter 9 Brakes
9.8 When bleeding the brakes, a hose is connected to the
bleeder valve at the caliper or wheel cylinder and then
submerged in brake fluid-air will be seen as bubbles in the
hose and container when the valve is opened - all air must
be expelled before moving to the next wheel
19 Remove one plug and push the piston assembly into the mastercylin-
der bore to expel the air from the master cylinder. A large Phillips screw-
driver can be used to push on the piston assembly.
20 To prevent air from being drawn back into the master cylinder the plug
must be replaced and snugged down before releasing the pressure on the
piston assembly.
21 Repeat the procedure until only brake fluid is expelled from the brake
line outlet hole. When only brake fluid is expelled, repeat the procedure
with the other outlet hole and plug. Be sure to keep the master cylinder
rez%vorrfrlled wtth brake fluio prevent the introduction of air into the sys-
tem.
22 Since high pressure is not involved in the bench bleeding procedure,
an alternative to the removal and replacement of the plugs with each
stroke of the piston assembly is available: Before pushing in on the piston
assembly, remove the plug as described in Step 19. Before releasing the
piston, however, instead of replacing the plug, simply put your finger tightly
over the hole @keep air from being drawn back into the master cylinder.
Wait several seconds for brake fluid to be drawn from the reservoir into the
piston bore, then depress the piston again, removing your finger as brake
..--- _a
fluid is expelled. Be sure to put your finger
back
over the hole each time
before releasing the piston, and when the bleeding procedure is complete
for that outlet, replace the plug and snug it before going on to the other port.
Installation
23 Install the master cylinder over the studs on the power brake booster
and tighten the attaching nuts only finger tight at this time.
24 Thread the brake line fittings into the master cylinder. Since the mas-
ter cylinder is still a bit loose, it can be moved slightly in order for the fittings
to thread in easily. Do not strip the threads as the fittings are tightened.
25 Fully tighten the mounting nuts and the brake fittings.
26 Fill the master cylinder reservoir with fluid, then bleed the master cyl-
inder (only if the cylinder has not been bench bled [see Steps 16 through
2.23 and the brake system as described in Section 9. To bleed the cylinder
on the vehicle,Tiave an assistant pump the brake pedal several times and
then hold the pedal to the floor. Loosen the fitting nuts to allow air and fluid
toescape. Repeatthisprocedureon bothfittingsuntilthefluidisclearof air
bubbles. Test the operation of the brake system carefully before placing
the vehicle in normal service.
8
Brake lines and hoses - inspection and replacement
i About every six months the flexible hoses which connect the steel
brake lines with the front and rear brakes should be inspected for cracks,
chafing of the outer cover, leaks, blisters, and other damage (Chapter I).
2 Replacement steel and flexible brake lines are commonly available
from dealer parts departments and auto parts stores. Do not, under any
circumstances, use anything other than genuine steel lines or approved
flexible brake hoses as replacement items.
3 When installing the brake line, leave at least 0.75 in (19 mm) clear-~
ante between the line and any moving or vibrating parts.
4 When disconnecting a hose and line, first remove the spring clip.
Then, using a normal wrench to hold the hose and a flare-nut wrench to
hold the tube, make the disconnection. Use the wrenches in the same
manner when making a connection, then install a new clip.
Note: MaI&
surethe tube passes through the center of/& grommet
5 When disconnecting two hoses, use normal wrenches on the hose fii-
tings. When connectingtwo hoses, make sure they are notbent, twistedor
strained.
6 Steel brake fines are usually retained along their span with clips. AI-
ways remove these clips completely before removing a fixed brake line.
Always reinstall these clips, or new ones if the old ones are damaged,
when replacing a brake line, as they provide support and keep the lines
from vibrating. which can eventually break them.
7 Remember to bleed the hydraulic system after replacing a hose or
line.
9
Brake system - bleeding
Refer to illustration 9.8
Warning:
Wear eye protection when bleeding the brake system. /f the
fluid comes in contact with your eyes, immediately rinse them with water
and seek medical attention.
Note:
Bleeding the hydraulic system b necessary to remove any air that
manages to find its way into thB system when it’s been opened during re-
movalandinsta/ation ofa hose, line, caliper, wheelcylnderormastercyl-
inder.
1 It will probably be
necessary
to bleed the system at all four brakes if air
has entered the system due to low fluid level, or if the brake lines have
been disconnected at the master cylinder.
2 If a brake line was disconnected only at a wheel, then only that caliper
or wheel cylinder must be bled.
3 If a brake line is disconnected at a fitting located between the master
cylinder and any of the brakes, that part of the system served by the dis-
connected line must be bled.
4 Remove any residual vacuum from the brake power booster by apply-
ing the brake several times with the engine off.
5 Remove the master cylinder reservoir cover and fitI the reservoir with
brakefluid. Reinstall thecover.Note: Check thefluidleveloftenduringth6
bleeding operation and add fluid as necessary to prevent the fluid level
from faalling low enough to allow air bubbles into the master cylinder.
6 Have an assistant on hand, as well as a supply of new brake fluid, a
clear container partially filled with clean brake fluid, a length of 3/l 6-inch
plastic, rubber or vinyl tubing to fit over the bleeder valve and a wrench to
open and close the bleeder valve.
7 Beginning at the right rear wheel, loosen the bleeder valve slightly,
then tighten it to a point where it is snug but can still be loosened quickly
and easily.
8 Place one end of the tubing over the bleeder valve and submerge the
other end in brake fluid in the container
(see illustration).
9 Have the assistant pump the brakes slowly a few times to get pres-
suretn the system, then hold the pedal firmly depressed.
10 While the pedal is held depressed, open the bleeder valve just
enough to allow a flow of fluid to leave the valve. Watch for air bubbles to
exit the submerged end of the tube. When the fluid flow slows after a
couple of seconds, close the valve and have your assistant release
the
pedal.
11 Repeat Steps 9 and 10 until no more air is seen leaving the tube, then
tighten the bleeder valve and proceed to the left rear wheel, the right front
wheel and the left front wheel, in that order, and perform the same proce
dure, Be sure to checkthe fluid in the master cylinder reservoir frequently.
12 Never use old brake fluid. It contains moisture which will lower the
boiling point of the brake fluid and also deteriorate the brake system rub-
ber components.
13 Refilt the master cylinder with fluid at the end of the operation.
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