Senior Member
Vintage RV Owners Club Fleetwood Owners Club iRV2 No Limits Club
Join Date: May 2014
Location: Gosnell, AR
Posts: 483
|
Here is what is in my p30 chassis manual about the parking brake:
SECTION 6 BRAKES
WHEEL CYLINDER LINKS
SECONDARY SHOE & LINING
SHOE GUIDE
PARKING BRAKE STRUT
STRUT SPRING
ADJUSTER LEVER
ACTUATING LINK -1 71
l0((
BRAKE SHOE
RETURN SPRINGS
0
OWNAAM
0
WHEEL
CYLINDER SCREWS
BACKING PLATE
HOLD DOWN I L ~-- HOLD DOWN SPRING
SPRING & CUP\ ADJUSTING SCREW SPRING
ADJUSTING SCREW
LEVER RETURN SPRINGS
J
HOLD _1
DOWN PINS
~ PARKING BRAKE LEVER
`- WHEEL CYLINDER
PRIMARY SHOE AND LINING
Figure 6-3-Typical Brake Drum Assembly
Figure 6-4- Power Brake Hydro-Boost
6-3
DRUM BRAKES
When the brake pedal is depressed, fluid is forced through
the brake lines into the piston . The wheel cylinder links
are then forced out against the brake shoes which exert
braking action on the drum . When the pedal is released,
the return springs pull the shoes away from the drum.
(See Figure 6-3 .)
POWER UNITS
Additional braking power is supplied through either a vacuum
booster or a Hydro-Boost. The master cylinder is
mounted on the forward end of the vacuum booster or
Hydro-Boost. (See Figure 6-4.)
The Hydro-Boost utilizes hydraulic pressure supplied from
the power steering pump. A spring accumulator is also
included in the booster to provide reserve braking power
in case pressure from the power steering pump is unavailable
. At normal curb idle with 150 lbs. of pedal pressure,
the Hydro-Boost could be expected to produce
1,600-1,850 lbs. of line pressure measured at any wheel
cylinder bleeder port. Similar pressures could be expected
of most vacuum boosters with good engine vacuum.
Figure 6-5- Parking Brake System
SECTION 6
Customers have expressed concern with their ability to
push the brake pedal to the floor with the vehicle stationary
and the engine running . If the Hydro-Boost brake pedal
is forced to the floor, as can be done, and the motion
stopping function and effectiveness of the brake system
is still considered normal, then the pedal travel action of
the Hydro-Boost brake system is also considered to be
normal . (See Pedal Travel Check in this section of the
manual.)
Figure 6-6
6-4
BRAKES
PARKING BRAKE(S)
Both the G-Series and P-Series are equipped with a parking
brake system. This system is mechanically operated
by a lever and strut or a pedal which will activate the rear
brakes only or the propshaft drum brake unit (P-Series
motor homes with a GVWR of 14,000 lbs. or more) . Very
little maintenance is required, but some periodic adjustment
is necessary . (See Figure 6-5.)
P-SERIES
WITH REAR WHEEL
PARKING BRAKES
WITH PROPSHAFT
PARKING BRAKE
CABLE TO
REAR WHEEL
BRAKES
NOTE: WITH REAR DRUM OR PROPSHAFT
DRUM PROPERLY ADJUSTED -
PROPER ADJUSTMENT OF THE
OPERATOR ORSCHELN PULL HANDLE
WILL REQUIRE 90 LBS. PULL OVER
FORCE.
See Figure 6-3 for typical brake drum assembly.
1 . Shoe Kit #1155270
' I/ 2. Drum &Flange #368008
SECTION 6
MAINTENANCE AND INSPECTION
FILLING THE MASTER CYLINDER
The master cylinder must be kept properly filled to ensure
adequate reserve and to prevent air from entering the
hydraulic system. However, because of expansion due to
heat absorbed from the brakes and from the engine, the
master cylinder must not be overfilled.
The -master cylinder is located under the floor on the
driver's side of the engine (P-Series), or on the cowl
(G-Series). The position of the master cylinder on the PSeries
may require the use of a flashlight and mirror to
check the fluid level .
Thoroughly clean the reservoir cover before removal to
avoid getting dirt into the reservoir . Remove the cover and
diaphragm. Add fluid as required to bring the level to
1/4 inch (plus or minus 1/8 inch) from the lowest portion
of the top of each reservoir . Use Delco Supreme No. II
Hydraulic Brake Fluid (DOT No. 3) or equivalent.
Do not use shock absorber fluid or any other fluid which
contains mineral oil . Do not use a container which has
been used for mineral oil or a container which is wet from
water. Mineral oil will cause swelling and distortion of rubber
parts in the hydraulic brake system and water will mix
with brake fluid, lowering the fluid boiling point. Keep all
fluid containers capped to prevent water contamination .
CAUTION : CHECK FOR LEAKS IF A LARGE AMOUNT
OF FLUID IS REQUIRED.
PEDAL TRAVEL CHECK
At periodic intervals, the motor home owner should inspect
the vehicle brake system for "pedal travel." Brake
pedal travel is the distance the brake pedal moves toward
the floor from the fully released position (foot not applied
to the brake). Brake pedal inspection should be made with
the brakes "cold ." With the engine turned off, depress the
brake pedal a minimum of four (4) times to exhaust all
vacuum and/or accumulator pressure . Applying approximately
90 pounds of pedal pressure, the distance the
brake pedal should travel is as follows :
G-Series with power brakes . . . . . . . . . . . . . . . . . . . . 3.5 inches
P-Series with drum rear brakes . . . . . . . . . . . . . . . . 3.5 inches
P-Series with disc rear brakes (JF9) . . . . . . . . . . 6.0 inches
BRAKE HOSE INSPECTION
The flexible hydraulic brake hose which transmits hydraulic
pressure from the steel brake pipe on the frame
to the rear axle and to the calipers should be inspected
regularly in accordance with the vehicle Maintenance
Schedule. The brake hose assembly should be checked
for road hazard damage, for cracks and chafing of the
outer cover, and for leaks and blisters . A light and mirror
may be needed for an adequate inspection. If any of the
above conditions are observed on the brake hose, it will
be necessary to replace it.
BRAKES
LINING INSPECTION
Inspect the brake linings per the vehicle Maintenance
Schedule and anytime the wheels are removed (tire rotation,
etc .) . Check both ends of the outer shoe by looking
at each end of the caliper . Check the lining thickness on
the inner shoe by looking down through the inspection
hole in the top of the caliper housing. Whenever the lining
is worn to the approximate thickness of the shoe, the shoe
and lining should be removed. After removal, measure the
lining thickness. The shoe and lining should be replaced
anytime the lining is worn to within 1/32 inch of a rivet or
of the shoe at any point, or when wear indicator contacts
the rotor. Always replace linings in sets (both right and
left front) .
Some front disc brakes have a wear indicator that makes
a noise when the linings wear to a degree where replacement
is required. (See Figure 6-6 .) The spring clip is an
integral part of the inboard shoe and lining . When the
lining is worn, the clip contacts the rotor and produces a
warning noise .,
Figure 6-7 - Disc Brake Wear Indicators
Check the flatness of the brake pads. Place inboard and
outboard pad surfaces together and check for a gap between
the pad surfaces . If more than a .005-inch gap is
measured at the middle of the pad (midway between attaching
lugs), the pad must not be used. This applies to
new or used brake pads. Whenever the front disc brakes
are relined, the rear brakes should also be checked .
BRAKE DRUM INSPECTION
Whenever brake drums are removed, they should be thoroughly
cleaned and inspected for cracks, scores, deep
grooves and out-of-round condition .
A cracked drum is unsafe for further service and must be
replaced . Do not attempt to weld a cracked drum.
Smooth up any slight scores. Heavy or extensive scoring
will cause excessive brake lining wear, and it will probably
be necessary to turn the drum on a lathe in order to true
up the braking surface.
If the brake linings are slightly worn and the drum is
grooved, the drum should be polished with fine emery
cloth but should not be turned . At this stage, eliminating
the groove in the drum would necessitate removal of too
much metal, while if left alone, the grooves and lining
ridges match and satisfactory service can be obtained .
If brake linings are to be replaced, a grooved drum should
be turned for use with new linings. A grooved drum, if
used with new lining, will not only wear the lining, but will
make it difficult, if not impossible, to obtain efficient brake
performance .
An out-of-round drum makes accurate brake shoe adjustment
impossible and is likely to cause excessive wear
of other parts of brake mechanism due to its eccentric
action . An out-of-round drum can also cause severe and
irregular tire tread wear as well as a pulsating brake pedal.
When the braking surface of a brake drum exceeds the
factory specification limits in taper and/or being out of
round, the drum should be turned to true up the braking
surface .
BRAKE ROTOR INSPECTION
To prevent brake roughness, the rubbing surfaces of the
rotor must be flat, parallel and with lateral runout held to
a minimum. The surface finish should be smooth to avoid
pulling or erratic brake performance . Light scoring which
results from normal use is not detrimental to brake operation
if the scoring does not exceed .015 inch in depth.
Lateral runout, the side-to-side movement of the rotor as
it rotates, if'excessive (over .004 inch total indicator reading),
can cause vibration when the brakes are applied . It
is checked using a dial indicator gage which a qualified
service shop should have.
DISC BRAKE SQUEAL OR SQUEAK
SECTION 6-BRAKES
A persistent amount of "squeal or squeak" is often associated
with heavy-duty disc brake usage. These noises
are common for both foreign and domestic disc brake
systems . Heat, humidity and severity of usage seem to
be contributing factors to brake noise. Changing the brake
pads, or rotor refinishing as a repair, is often considered
a temporary repair, or even, by some technicians as useless.
The recommended aproach is to have an inspection
to assure there is free and proper operation of all caliper,
parts. At this point, the owner should realize that the brake
noise exists, but is not detrimental to overall brake life.
BRAKE CALIPER NOISE
Sometimes on vehicles with high mileage, a noise or rattle
condition caused by wear at the brake caliper and knuckle
slide surfaces may be encountered. This condition does
not affect the operation of the brake system, but the noise
or rattle condition can be corrected by installing an oversized
key and spring available as a service replacement.
GM Bulletin 79-T-25 (Jan . 1980) in Appendix 6-1 at the
back of this section provides details for selecting the
proper size replacement key and how to install the key.
BRAKE PEDAL/STOPLIGHT ADJUSTMENT
NOTE: The adjustments listed below do not change with
time or miles. An incorrect adjustment would normally
be noted in the first few miles of vehicle life
or after service work of some kind performed under
the dash resulting in system malfunction .
1 . Check for a full upward and full release of the brake
pedal. Determine if the stoplight switch, cruise control
switch or any other item does not allow full upward
pedal travel. (See Figure 6-7.) The stoplight switch/
brake pedal mounting bracket provides automatic adjustment
when the brake pedal is manually returned
to its mechanical "up-stop" position .
2. Pull the brake pedal fully rearward against the pedal
stop until audible "click" sounds can no longer be
heard . This moves the stoplight switch assembly in a
tubular clip, as shown in Figure 6-7, and provides a
proper adjustment.
NOTE : Proper adjustment of the stoplight switch allows
.06 inch to .36 inch free pedal travel and will turn
on the stoplight switch after approximately .40
inch travel. (See Figure 6-8 .)
BRAKE PEDAL
MOUNTING BRACKET
CRUISE CONTROL
ONLY
(WITH CRUISE CONTROL)
(WITHOUT CRUISE
CONTROL)
NOTE: Refer to bulletin section on pads that will help
reduce brake noise on pre 1992 units. Figure 6-8 - Brake Pedal/Stoplight Switch Assembly
6-6
3. Check the 31-inch rod that runs down the front of the
chassis and connects the brake pedal to the Hydro-
Boost for proper adjustment. (See Figure 6-8 .) The rod
can be adjusted (longer or shorter) using the screw
adjustment located at the bottom of the rod . Block the
wheels and hold the inside pedal in the "full-up" position
. Check that there is free entry of the special bolt
through the relax4d pedal rod lever connecting the
linkage into the Hydro-Boost. Turn the adjustment
screw to lengthen or shorten the rod as necessary.
4. Tighten the adjusting lock nut to 22-30 ft. lbs. then
tighten the nut on the special bolt and install a new
cotter pin .
NOTE : Newer model rods can not be adjusted.
SECTION 6
PEDAL BUMPER
.06" TO .36" FREE
PEDAL TRAVEL
.40" PEDAL TRAVEL
REQUIRED TO TURN
STOPLAMP SWITCH ON
PEDAL ROD LEVER
PEDAL ROD END
Figure 6-9 - Actuating Rod/Brake Pedal/Stoplight
Adjustment
BLEEDING BRAKE HYDRAULIC SYSTEM
A bleeding operation is necessary to remove air whenever
it is introduced into the hydraulic brake system .
It may be necessary to bleed the hydraulic system at all
four wheel cylinders if air has been introduced through
low fluid level or by disconnecting the brake pipes at the
master cylinder. If a brake pipe is disconnected at any
wheel cylinder, then that wheel cylinder only needs to be
bled. If pipes are disconnected at any fitting located between
the master cylinder and wheel cylinders, then all
wheel cylinders served by the disconnected pipe must be
bled.
BRAKES
NOTE : The following procedure is for manual bleeding
of the brakes only. If possible, obtain approved
commercial pressure-bleeding equipment or the
GM Tools Vacuum Brake Bleeder. (See the GM
Wheel Service System Brake Bleeder in Appendix
6-2 at the back of this section for further information
regarding Brake Bleeder specifications,
usage and ordering information .)
With power brakes, remove the vacuum reserve by applying
the brakes several times with the engine off . Then,
complete the following steps:
1 . Fill the master cylinder reservoirs with brake fluid and
keep at least one-half full of fluid during the bleeding
operation. (See Figure 6-1 .)
2. If the master cylinder is known or suspected to have
air in the bore, then it must be bled (before bleeding
any wheel cylinder or caliper) in the following manner:
a. Disconnect the forward (blind end) brake pipe connection
at the master cylinder.
b. Allow brake fluid to fill the master cylinder bore until
it begins to flow from the forward pipe connector
port.
c. Connect the forward brake pipe to the master cylinder
and tighten .
d. Depress the brake pedal slowly one time and hold.
Loosen the forward brake pipe connection at the
master cylinder to purge air from the bore. Tighten
the connection and then release the brake pedal
slowly. Wait 15 seconds. Repeat the sequence, including
the 15-second wait, until all air is removed
from the bore. Care must be taken to prevent brake
fluid from contacting any painted surface.
e. After all air has been removed at the forward connection,,
bleed the master cylinder at the rear (cowl)
connection in the same manner as the front, as in
Step "d" above.
f. If it is known that the calipers and wheel cylinders
do not contain any air, then it will not be necessary
to bleed them.
3. Individual wheel cylinders or calipers are bled only after
all air is removed from the master cylinder.
a. Place a proper size box-end wrench over the
bleeder valve. Attach transparent tube over valve
and allow tube to be hand submerged in brake fluid
in a transparent container . Depress the brake pedal
slowly one time and hold. Loosen the bleeder valve
to purge the air from the cylinder. Tighten bleeder
screw and slowly release pedal. Wait 15 seconds .
Repeat the sequence, including the 15-second wait
until all air is removed. It may be necessary to repeat
the sequence ten or more times to remove all
the air.
4 . If it is necessary to bleed all of the wheel cylinders and
calipers, the following sequence should be followed :
1) Right-rear wheel cylinder; 2) Left-rear wheel cylinder;
3) Right-front caliper ; 4) Left-front caliper .
5. Check the brake pedal for "sponginess" and the brake
warning light for indication of unbalanced pressure .
Repeat entire bleeding procedure to correct either of
these two conditions.
BLEEDING HYDRO-BOOST BRAKE SYSTEM
Whenever the booster is removed and reinstalled, the
steering system should be bled as outlined below.
NOTE: Power steering fluid and brake fluid cannot be
mixed. If brake seals contact steering fluid or
steering seals contact brake fluid, seal damage
will result.
1 . Fill fluid reservoir to the proper level and let the fluid
remain undisturbed for at least two minutes.
2. Start the engine and let it run momentarily.
3. Add fluid if necessary.
4. Repeat above procedure until the fluid level remains
constant after running engine.
8. Lower the vehicle .
SECTION 6
5. Raise front end of the vehicle so that the wheels are
off the ground .
6. Turn the wheels (off ground) right and left, lightly contacting
the wheel stops.
7. Add fluid if necessary.
9. Start engine and depress the brake pedal several
times while rotating the steering wheel from stop to
stop .
10. Turn engine off and. then pump the brake pedal 4-5
times to deplete accumulator pressure.
11 . Check the fluid level and refill as required .
12. If fluid is extremely foamy, allow vehicle to stand for
a few minutes with the engine off and repeat above
procedure .
a. Check belt tightness and check for a bent pully.
(Pulley should not wobble with engine running .)
b. Check to make sure hoses are not touching any
other parts of the vehicle, particularly the sheet
metal.
6-8
BRAKES
c. Check the reservoir fluid level, filling it to the proper
level if necessary, following operations 1 through
10. This step and step "d" are extremely important
as low fluid level and/or air in the fluid are the most
frequent causes of objectionable pump noises.
d. Check for the presence of air in the fluid. Air will
show up as a milky-looking fluid. If air is present,
attempt to bleed the system as described in operations
1 through 10. If it becomes obvious that
the pump will not bleed after a few trials, refer to
the appropriate shop manual for more detailed test
procedures.
13. The presence of trapped air in the system will cause
the fluid level in the pump to rise when the engine is
turned off. Continue to bleed the system until this
condition no longer occurs.
POWER BRAKE UNITS
The hydraulic lines connecting the power steering pump,
Hydro-Boost unit and steering gear, as well as the components
themselves, should be checked regularly for
signs of leaks, damage or deterioration on vehicles so
equipped . For vehicles with vacuum boosters, inspect the
vacuum hoses and booster chamber for damage or
deterioration .
NOTE: Power steering fluid and brake fluid cannot be
mixed . If brake seals contact steering fluid or
steering seals contact brake fluid, seal damage
will result.
Both the vacuum booster and Hydro-Boost should be
serviced by a qualified repairman .
PARKING BRAKE
Adjustment of the parking brake cable is necessary whenever
holding ability is not adequate or whenever the center
brake cables have been disconnected . An improperly adjusted
parking brake cable may also cause the brakes to
drag. On 16,000# GVW units, the transmission must be in
neutral .
The service brakes must be properly adjusted as a base
for parking brake adjustment ; conversely, the parking
brake must be properly adjusted for the service brake to
function as intended .
Inspection
If a complete release of the parking brake is not obtained,
unless it is forcibly returned to its released position, or if
application effort is high, check parking brake assembly
for free operation. If operation is sticky or a bind is experienced,
correct as follows :
1 . Clean and lubricate brake cables and equalizer with
Delco Brake Lube (or equivalent) .
2. Inspect brake assembly for straightness and alignment
(replace if necessary).
3. Clean and lubricate parking brake assembly with Delco
Brake Lube (or equivalent) .
4. Check routing of cables for kinks or binding .
Drum Balance
An imbalanced parking brake drum can cause vibrations .
If a vibration occurs, perform the following to check for an
imbalance problem with the parking brake drum :
1 . Place the transmission into NEUTRAL and increase
the engine speed to the approximate speed that the
vibration is felt while driving the vehicle on the road .
2. If the vibration has disappeared, check the parking
brake drum on the back of the transmission if so
equipped.
3. Disconnect the propeller shaft at the back of the transmission
and remove the drum .
4. Retest as in Step 1; If the vibration is gone, replace
the drum. (See Figure 6-9 .)
NOTE: If a strobe light wheel balancer is available, position
the strobe pick-up against the transmission
pan. Adapt the procedure listed in the Driveline
Balance section of this manual to check for a
balanced drum. Add weight under the retaining
bolt of the parking brake drum as necessary .
Cable Adjustment
FOOT PEDAL TYPE (G-P series) - Before adjusting
parking brake, check service brake condition and
adjustment.
1 . Loosen the equalizer adjusting nut .
2. Apply parking brake four notches from fully released
position. Only 1 notch on P series .
3. Tighten the equalizer nut until a moderate drag is felt
when the rear wheels are rotated forward. (See NOTE
at the end of this procedure .)
4. Fully release parking brake and rotate the rear wheels.
No drag should be present.
ORSCHELN LEVER TYPE (P-SERIES) -
1 . Turn adjusting knob on parking brake lever counterclockwise
to stop.
2. Apply parking
SECTION 6-BRAKES
6-9
3. Loosen nut at intermediate cable equalizer and then
adjust nut to give light drag at rear wheels. (See NOTE
at the end of this procedure .)
4. Readjust parking brake lever knob to give a definite
snap-over-center feel . Proper pull-over force is 90
pounds.
NOTE: This fastener is an important attaching part in that
it could affect the performance of vital components
and systems, and/or could result in major
repair expense. It must be replaced with one having
the same part number or with an equivalent
part if replacement becomes necessary. Do not
use a replacement part of lesser quality or substitute
design ;
Propeller Shaft Drum-Type Brake
Adjustment (Adjustment - Drum On)
Refer to Figure 6-9 .
1 . Using a jack, raise vehicle so that at least one rear
wheel is off ground . Block wheels and release the hand
brake.
2. Remove cotter pin and clevis pin connecting the pull
rod and relay lever. This will assure freedom for full
shoe release .
NOTE : It may be necessary to knock out lanced area in
brake drum (or backing plate) with punch and
hammer to gain entry to adjusting screw through
brake drum . Be sure to remove any metal that
has fallen inside the parking brake drum.
3. Rotate brake drum to bring one of the access holes
into line with adjusting screw at bottom of shoes (manual
transmission), or top of shoes (automatic
transmission) .
4. Expand shoes by rotating adjusting screws with a
screwdriver inserted through hole in the drum . Move
outer end of screwdriver away from the drive shaft.
Continue adjustment until shoes are tight against drum
and drum cannot be rotated by hand. Back off adjustment
and check drum for free rotation .
5. Place parking brake lever in the fully released position .
Take up slack in the brake linkage by pulling back on
cable just enough to overcome spring tension . Adjust
clevis of the pull rod or front cable to line up with hole
in the relay levers .
a. Insert clevis pin and cotter pin,-then tighten clevis
locknut .
b. Install anew metal hole cover in drum to prevent
contamination of the brake.
c. Lower rear wheels. Remove jack and wheel blocks.
See Note under Cable Adjustment procedure in this
section .
It sounds to me like you do not have to disconnect the drive shaft, it appears the drum brake is adjusted with the drive shaft in place. I am sorry the pictures did not copy.
Good Luck
__________________
Berniece & Russell with LilBit a Netherland Dwarf rabbit
1987 Southwind, 1995 Ford F150 Supercab 4X4 toad
Life in the fast lane? No thanks! We will stop and smell the flowers at every chance.
|