This assumes the brake MC has been mounted back
on the truck, the pedal height has been set, the return spring has been reconnected,
and the push rod clearance has been set properly.
To bench bleed your master cylinder
you will need some VERY sophisticated tools. NOT! :-) Follow along as we try
this horribly complicated bit of brake bleeding wizardry:
Bench Bleeding
Fig. 10
Get two 12" pieces of 1/8"
vacuum line or better yet clear aquarium air line.
If you have a bunch of old brake
lines laying around with the 10mm male flare ends then cut off two sections
about 2" long with the flare end still attached. If you don't then go
to the parts store and buy the shortest metric brake line they sell and cut
it down to size.
Thread the 10mm fittings into each port of
the master cylinder. Tighten them down.
Push the air/vacuum lines over the ends of
the cut off brake lines then using some clothes pins or other type clamps
clamp them to the sides of the reservoir cups as shown in Fig.
10.
Fill the cups with your favorite clean brake
fluid.
SLOWLY start pumping the brake pedal. With
each pump fluid and air bubbles will come out of the lines. Don't let the
fluid level get below the vacuum lines or they will suck air back in! Keep
slowly pump the pedal until no more air bubbles appear.
Disconnect the bench bleeding lines and reconnect
the real ones. Bleed the brakes as outlined below.
Bleeding/Adjusting the 8, yes EIGHT, Wheel
Cylinders
Tools/Parts
Description/Job
10mm flare nut wrench
To loosen/tighten bleeders
Piece of 1/8" clear hose
Attach to bleeder to direct brake fluid to jar.
Small jar any size
To hold expelled brake fluid.
2 qt's Brake Fluid
Duh...
Large Straight Screwdriver or the SST
For turning the adjusters
You knew this day was coming. You've put it off,
tried to bribe friends to do it for you, (or at least help you do it for beer), considered
converting to disk just to keep from doing it, ah hell, admit it, you've even
considered paying someone else to do it! But in the
end, after several near death experiences and all that wasted mental thought,
you decide to do it yourself...
So here you are on a beautiful sunny warm Saturday
morning. Your buds are out wheeling and you are standing in the driveway with
tears in your eyes, coffee in one hand and a gallon of brake fluid in the other.
The very thought of starting this job makes you want to put a curse on the engineer
who thought that eight wheel cylinders would be cool. Well my friend, bleeding eight
wheel cylinders is not cool, it's not even trick. IT SUCKS!
While a vision of the afore mentioned engineer
buried under a pile of J**p parts brings a fleeting smile to your lips, you
grit you teeth and approach the old Cruiser ready to take on this job.
Start by putting the truck on jack stands on a level surface.
Remove all 4 tires and the drivers side rear brake drum. Warning! You may have
to turn the wheel cylinder adjusters to pull the shoes in a bit in order to get the drums off. If the adjuster are frozen solid you may have to resort to unbolting BOTH wheel cylinders then driving them out of the backing plate to collaspe the shoes inward!
Inspect the cylinders for ANY signs of leakage. Even if you just rebuilt them! No point
in continuing if you have leaky cylinders!
Start with the drivers side rear brake. Determine which direction
you need to turn the adjusters to expand the shoes. If you have all proper
cylinders in the proper place then the cylinder on the back (the one with the adjuster
pointed at ground) needs to turn clockwise to expand. The other will turn
counter clockwise. Adjust the shoes out in EQUAL amounts until you can barely
get the drum over them. Count the exposed threads on the adjusters as guides
to keep them even.
Put the drum back on the hub. Continue to adjust one adjuster until you can hear the brake shoe dragging a bit. Move to the other side and repeat. Continue alternating between adjusters until the shoes are dragging
heavily on the drum but you can still force it to turn by hand.
Repeat this for the other 3 brakes. This gets ALL the shoes
as close to the drum as possible before starting the bleeding process. The closer they are, the less distance they
have to travel and the less fluid needed to start braking action. This will later translate
into a FIRM pedal with NO pumping to get GOOD brakes!
Return to the rear drivers side brake.
Loosen the brake bleeder screw about 1/2 turn. Attach the
clear line to the nipple. Put the other end in the jar then add enough clean
brake fluid to cover the end of the hose.
Make SURE the Master cylinder is topped off with clean brake
fluid.
Get in the truck and SLOWLY push the brake pedal to the floor.
Now SLOWLY release it. Repeat this FOUR times then top off the master cylinder.
Don't forget to top off the master cylinder after every 4-5 pumps!
Check the fluid in the jar. If it's dark looking or contains
rust particles then pour it out and again add clean brake fluid to cover the
hose end. Repeat steps 9-11 until the fluid is clear. This may take awhile.
This flushes out the old brake fluid and any rust or water in the lines. You are also
removing any air bubbles in this line.
Once the fluid is clear then close the bleeder valve and remove the line from the nipple.
Repeat steps 8-12 for the front cylinder on this brake. It won't take near as long to get clear fluid as you are just flushing this cylinder, not the entire line.
Move to the passenger side rear brake and repeat steps 8-12.
Move to the passenger front brake and repeat steps 8-12.
Move to the drivers side front brake and repeat steps 8-12.
After doing each brake you should have felt the pedal getting
firmer and firmer. If you don't have good pedal at this
time then something else is wrong. Stop and figure it out before continuing!
If you have a firm pedal then put the tires back on but leave the truck on the jack stands.
Have a helper spin each wheel as fast as they can while you slam on the brakes hard. This will center the shoes on the backing plate. Repeat steps 5 and 6 to ensure ALL the brakes are still dragging slightly.
Check your emergency brake, if it's not working FIX IT NOW! Someones life may be depending on your brake repair skills!
Drive the truck to a deserted area and do some brake tests. The truck should stop straight and true with no lockup of any one wheel before another.
If you have a good pedal with no pumping but it SLOWLY sinks
to the floor when held then it's time for a Master Cylinder rebuild or replacement.
If you still have to pump several times to get a pedal but it
does NOT sink when held then it could be that you missed a shoe adjustment somewhere
or your booster push rod need to be adjusted out some more. This adjustment
also affects the pedal height.
When you are done you should have GREAT brakes! My Cruiser
will lock up all 4 tires with NO problem.
