Inline Tube - Rear Drum Brake Restore
Inline Tube - 9 1/2" GM Rear Drum Brake Restore
Drum brakes is one of those areas that nobody wants to work on. There is so many
springs and other parts that have to go together, it is a nightmare. If the parts are
rusty it makes it 100 times worst. This article will show the complete rebuild of
the very common 9 1/2" GM rear drum assembly. This assembly was used on
countless cars in the 60's an 70's. Applications include:
1964-72 GM A-body Chevelle, GTO, 442, Gran Sport, Monte Carlo, Grand Prix
1967-69 GM F-body Camaro, Firebird, Trans Am
1968-74 GM X-body Nova, Ventura, Apollo, Omega
1970-81 GM F-body Camaro, Z28, Firebird, Trans Am
Now that your brakes are 30 - 40 years old it is time to take a look and see
what is left. If the shoes are worn out maybe it is time to replace all the
hardware since it all has to come apart to get the shoes out. Another thing to
remember is there is a difference between the right and left side so do one side
at a time and do not mix the parts together. Inline tube offers a complete line
of drum parts so if you just need a spring kit or a wheel cylinder it is no
problem. If your system is in need of a complete overhaul Inline Tube also
offers the complete set assembled and ready to bolt on. The complete set comes
as a unit with all the correct color coated springs, plated hardware, parking
brake arm and other hardware that is not available anywhere. When you consider
the cost of rebuilding all the pieces including turning the drums and re-painting or plating the parts the complete unit really takes the work out
and saves money. The complete unit is around $400 or all the parts could be as
much as $600 and you still have to do all the assembly.
By following the steps below you can
rebuild you components just like an experienced mechanic. Inline Tube offers all
the pieces of the rebuild or the bolt on unit ready to
bolt onto your classic.
Here is an original drum brake set off a 69 GTO, all the parts are in great
shape and will make this restoration much easier. When you take apart the drums
you must evaluate the parts and consider the condition and the time it will take
to restore an old part verses the cost of a new part. In this restore we have
taken the harder road and are going to restore the old parts. All the springs
and hardware have been bead blasted and repainted the factory correct colors and
the parking brake arm, and other hardware has be phosphated. A few parts have
been sent out to be silver and gold zinc plated which takes a week to get back.
When working on drum brakes no special tools
are necessary but there are 2 tools that can really save some time. The red
handled tool will help to get the shoe springs held down and turned into place.
Pliers can be used in place of this tool but often scratch up the parts. The
second tool is the spring bar. This tool is designed to get the springs back
into place, it has a special end so the spring slides into place. A screw driver
after several attempts and a possible pinch of the finger will achieve the same
result. The hardware is now back from being plated and the color hardware is now
dry. The wheel cylinders were rebuilt in the article Wheel Cylinder
Rebuild or click here to view.
This is the left assembly we are working on.
The drum shoes are riveted and glued just like factory, provided by Inline Tube.
The backing plate is phosphate with the back painted black. At the factory the
brake assembly was installed to the axle with the drum and then the black paint
was sprayed on everything. The first step is to snap the parking brake cable
into the backing plate and next the wheel cylinder can be bolted in.
The shoes look alike and will fit either side
so be careful to install correctly. The shoe with the long pad goes to the rear
of the car. At this time the parking brake cable must be hooked to the parking
brake arm and hooked into the rear shoe. The adjuster arm is set into place with
the orange spring ready to be hooked in.
With the special red tool push the spring
down and twist while holding the pin on the back side. It will lock into place.
Now install the small red spring at the base of the adjuster and hook the 2
shoes together with the other red spring and the cylinder adjuster between the
shoes. The teeth of the adjuster will line up in front of the hole in the
backing plate, beneath the adjuster arm. Hook the brown spring from the adjuster
arm to the backing plate stud but be sure to install the washer with ears first.
With the bar tool or screwdriver install the pink spring from the shoe to the
backing plate stud.
Half the assembly is now done and the
other half will have to have the blue shoe. Hold down spring installed and the
light blue spring installed from the shoe to the backing plate stud. Flip
over the assembly install the blue bleeder cap and rubber dust plug.
We now assemble the right hand side which is
a mirror image of the other side. This can be tricky since many of the parts
look exactly the same but are the opposite. The steps are the same as above.
Again remember to install the long shoe to the back of the car.
The cylinder adjuster teeth go over the open
slot in the backing plate and should be in the full closed position. These are
self adjusters so when the car is all put back together in reverse motion
lightly apply the brakes and the shoes will automatically adjust out to the
right position. As the shoes wear down and the car gets put in reverse the
adjusters will continue to take up the slack in the system.
The drum assembly is held to the axle flange
by four bolts. To install the backing plate the axle must be removed. This is
again held on by the four flange bolts. For Pontiac, Buick, and Oldsmobile the axle
is held in by the bolts, on Chevrolet products there is an additional c clip
that will have to be removed. This c clip is located under the rear end cover.
Drain the oil, remove the cover, pull the clip, then remove the axles.
The drums have been installed and the axle is
ready to be installed in the car.
As we spoke of earlier to save time, money,
and frustration the assembly is available exclusively from Inline Tube ready to
bolt on. This assembly is exact to the factory original featuring correctly
colored components and finned drums. The complete setup pictured above retails
for around $400.00
Inline Tube - Brake & Fuel Lines,
Caliper Rebuild Kits, Brake Hardware, Disc Brake Conversions
15066 Technology Drive
Shelby Twp, MI 48315
Palmetto Enterprises - Grey Phosphate Plating
2311 A Old Parker Road
Greenville, SC 29609
(864) 246-3836 ph
Bobís Boosters - Silver, Gold, Black Zinc Plating