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Step 1 - Locate the Brake Booster
The brake booster is located adjacent to the master cylinder. There will be 4 mounting screws protruding through the booster. The booster is also attached to the brake pedal in the interior of the car. This is where you will start work in replacing the brake booster.
Step 2 - Remove the Brake Booster
Start by locating the booster rod that goes through the firewall and is attached to the brake pedal on the interior of the car. Typically, there is a cotter pin that secures the rod to the pedal, but there may also be nuts. When removing any fasteners in the course of this job, make sure to retain the nuts, cotter pins, and various other fasteners as the new brake booster will not come with replacement fasteners.
Remove the fasteners, whether it is a cotter pin or nuts. Slide the rod off the brake pedal. Disconnect the vacuum brake line that connects to the booster. In the engine compartment, there are four bolts securing the booster to the master cylinder and firewall. Loosen and remove these nuts. Remove the nuts (there are usually 2 in addition to the 4 that have already been removed) that secure the brake booster to the master cylinder. Wiggle the brake booster away from the master cylinder. There is a seal between the two. You will need to keep this as the new part does not generally come with another one. Remove the brake booster.
Step 3 - Install the New Brake Booster
Set the new brake booster on the four mounting screws. Tighten the nuts on the bolts to the master cylinder. Insert the push rod through the firewall. Start these by hand so that the threads are not ruined. Reattach the vacuum hose, then the nuts to the 4 mounting screws. Reattach the push rod to the brake pedal by whatever means it was originally secured with, whether by cotter pin or by bolts.
Step 4 - Bleed the Brakes
You will need to bleed the brakes after replacing the brake booster
The power brake booster is a tandem vacuum suspended unit. Some
models may be equipped with a single or dual function vacuum switch
which activates a brake warning light should low booster vacuum be
present. Under normal operation, vacuum is present on both sides of the
diaphragms. When the brakes are applied, atmospheric air is admitted to
one side of the diaphragms to provide power assistance.
REMOVAL & INSTALLATION
1994-97 Models See Figures 1 and 2
Apply the parking brake and block the drive wheels.
Remove the master cylinder-to-power brake booster nuts, then
reposition the master cylinder and combination valve out of the way; if
necessary, support the master cylinder on a wire to prevent damaging the
When removing the master cylinder from the power brake booster, it is
not necessary to disconnect the hydraulic lines, therefore the brake
system should not have to be bled.
Disconnect the vacuum hose from the power brake booster.
Fig. Fig 1: Common power brake booster attachment
From under the dash, remove the retainer and washer from the brake
pedal on 1994 utility models. On all other models, remove the retainer
and brake switch from the brake pedal.
Disconnect the pushrod from the brake pedal.
From under the dash, remove the power brake booster-to-cowl retaining nuts.
Back under the hood, remove the power brake booster and the gasket from the cowl.
Position the booster to the cowl using a new gasket.
Install the booster retaining nuts and tighten to 16 ft. lbs. (22
Nm) 1994 utility models, 24 ft. lbs. (32 Nm) on 1994 pick-up models and
27 ft. lbs. (36 Nm) on all 1995-97 models.
Connect the pedal pushrod and install the washer or switch and the retainer.
Connect the vacuum hose.
Fig. Fig. 2: Checking the piston booster rod using the gauge tool
For all vehicles covered in this guide, gauge the booster rod:
Apply 25 in. Hg (85 kPa) of vacuum using a hand held vacuum pump or apply maximum engine vacuum.
Check the maximum and minimum rod lengths using J-37839 or an equivalent pushrod height gauge.
If the piston is not within limits, install a service adjustable piston rod and adjust it to the correct length.
Reposition the master cylinder and combination valve bracket to
the booster studs, then secure using the retaining nuts. For details,
please refer to the master cylinder procedure located earlier in this
Start and run the engine, then check for proper booster operation.
check all brake lines and wheel cylinders for leakage. if no leaks its probably the master cylinder. symtoms are-- pedal will sink to floor when stopping or not. or master cylinder leaks from behind "it", and runs down brake booster. if booster goes bad the pedal will be very hard! good-day !
#1) Check and make sure your Power brake boosters Hose is not Cracked or just not a tight fit going to Intake.
#2) Since you Have Rear Drum Brakes You might have left to much Brake to Drum Clearance==Ajust rear Brakes out to Just give you good clearance to slide Drum Over Brakes.
#3) Check all your Brake Lines for Possible leaks.
#4) CHECK to make sure your Accuating Rod from your Brake Pedal to your Power Brake Booster is in the Rear of Boosters Piston that whenb you apply brake its Acctuating the Power Booster.
#5) Also did you bench bled your Master before instaling? If not you'll have to bled your master clylinder 1st, and then Start at farest wheel from master cylinder and work your way to the brakes on front Drivers side.
#6) only other thing that comes to mind is your Anti Brake Module.
Hope this has helped you ,PLEASE let me know by Voting For the Soultions i've Given You.
The booster is working properly if the pedal goes down a little when starting the truck. Seems more like it's a master cylinder problem if it won't pump up.
REMOVAL & INSTALLATION
Fig. 1: Disconnect the warning indicator at the master cylinder
Fig. 2: Remove the fluid to minimize the amount that would otherwise inevitably be spilled
Fig. 3: Unscrew the line fittings at the master cylinder
Fig. 4: Hold a rag under the fittings to keep fluid from dripping all over things
Fig. 5: Unbolt the master cylinder from the brake booster
Fig. 6: Remove the master cylinder from the vehicle and set it in a clean location
Disconnect the negative battery cable.
Apply the brake pedal several times to exhaust all the vacuum in the system.
Detach and cap the brake lines from the master cylinder.
If equipped, detach the brake warning indicator connector.
NOTE: A turkey baster (tapered tube with a squeeze ball on top) works well for removing fluid from the reservoir (see photo).
Siphon off the fluid from the master cylinder reservoir to minimize spillage when lines are disconnected.
If applicable, disconnect and cap the Hydraulic Control Unit (HCU) supply hose at the master cylinder reservoir and secure in a position to prevent loss of fluid.
Unfasten the 2 nuts and lockwashers that attach the master cylinder to the brake booster.
Remove the master cylinder from the booster by sliding it forward and upward from the vehicle.
Install a new seal in the groove in the master cylinder mounting face.
Position the master cylinder assembly over the booster pushrod and onto the 2 studs on the booster assembly.
Install the retaining nuts, then tighten to 18–25 ft. lbs. (24–34 Nm).
Uncap and connect the brake lines to the master cylinder. Tighten the front fitting to 16–21 ft. lbs. (21–29 Nm), and the rear fitting to 10–15 ft. lbs. (15–20 Nm).
Uncap and connect the HCU hose to the master cylinder reservoir fitting and secure with a hose clamp.
If equipped, connect the brake warning indicator.
Fill the master cylinder with Heavy Duty Brake Fluid C6AZ-19542-AA or equivalent DOT 3 brake fluid from a clean, sealed container. Bleed the entire brake system, as outlined in this section.
Connect the negative battery cable.
Operate the brake several times, then check for external hydraulic leaks.
a defective master has just one common symptom, a soft sinking pedal.
Things You'll Need:
Ratchet and socket
Slip joint pliers
New cotter pin
Removing the Old Brake Booster
Park your car in a safe place with enough room to work around the front and driver side of the vehicle.
Locate the booster push rod connected to the brake pedal.
Remove the cotter pin securing the booster push rod pin to the brake pedal using a pair of nose pliers.
Release the push rod pin from the brake pedal and slide the push rod off the brake pedal.
Unscrew the four mounting nuts off the brake booster studs using a ratchet, ratchet extension and socket. You should be able to see the four booster studs extending through the firewall, in front of the brake pedal.
Disconnect the vacuum hose from the brake booster, working from the engine compartment. Use a pair of slip joint pliers.
Remove the two nuts holding the brake master cylinder to the brake booster. Use a wrench or ratchet and socket.
Separate the brake master cylinder from the booster just enough to make room for booster removal.
Pull the brake booster off the firewall and remove it from the vehicle.
Installing the New Brake Booster
Set the new booster in place by sliding the push rod and four mounting studs through the mounting holes on the firewall.
Slide the brake master cylinder flange over the two mounting studs on the brake booster.
Start the two brake master cylinder mounting nuts by hand to avoid damage to the threads.
Tighten the two brake master cylinder mounting nuts using a wrench or ratchet and socket.
Connect the vacuum hose to the brake booster.
Screw the four mounting nuts to the brake booster working from inside the vehicle. Start the nuts by hand to avoid damaging the threads.
Tighten the four mounting nuts using the ratchet, ratchet extension and socket.
Position the brake booster push rod over the brake pedal and slide the push rod pin.
Install a new cotter pin to secure the booster push rod to the brake pedal
get ready for some work.you need to remove the master cylinder nuts that hold master cylinder to brake booster.once you remove nuts you have 2 choices remove master cylinder to remove booster. to keep from bending brake lines.or you can leave master cylinder in pull it toward you easily careful dont bend lines .disconnect vacuum line at booster .go inside vechicle to floor on driver side loosen four nuts on floor to booster .disconnect power brake push rod from brake pedal .dont force pushrod to the sides when disconnecting it.remove four booster nuts then remove booster.when in stalling the new booster loosely install four nuts then connect the push rod to the brake pedal .install new clip tighten the booster unit .if you decide to remove master cylinder use inline wrenches on master cylinder to remove lines.also plug the master cylinder brake line holes to keep from losing all brake fluid.