Hi there, I'm Brady from the outside sales department here at Gregg Distributors. Today
on Gear up with Gregg's we're going to put it in park and do a quick walk through on
Spring Brake Chambers.
Air brake chambers are basically round metal
containers located near each wheel of any heavy truck, trailer, tractor, or other industrial
vehicle that uses air brakes. In order to bring you to a safe stop, air brakes convert
compressed air into mechanical force, which in turn applies the brakes. However, not all
air brake chambers are the same as there are two different types service and spring.
A service brake chamber has one function: to apply and release the brakes. At its most
basic level, a service brake works much like a regular hydraulic brake in a commuter car,
the only difference is that one uses hydraulic fluid while the other uses compressed air.
Let's take a closer look. Internally the service brake has a rubber disc called a diaphragm,
a push rod, and a return spring.
When you're driving and you press on the brake pedal, compressed air fills the service brake chamber
which causes the diaphragm to move and push out the push rod. This in turn causes the brakes to apply.
Then when you release your foot from the brake, the air pressure is released and the pushrod returns to its resting position thanks to the return spring.
However, spring brakes use a different type of brake chamber. While service brakes have only one function, the spring brake chamber has two sections that do two different jobs.
The front section acts as a service chamber and has the same internal components as the service brake mentioned previously.
The GDX Spring brake Chamber has high quality rubber diaphragms with reinforced nylon fabric.
The rear section has a very powerful, heat fused, epoxy coated spring that acts as a
parking or emergency brake when air pressure is lost.
The spring brake section is piggy-backed onto the service brake section and these two sections function as two separate chambers.
Spring brakes are not applied with pressurized air like service brakes,
instead they are applied when air pressure leaves the brake chamber and they are released when the air pressure builds back up.
Connecting both chambers is the push rod, which moves to engage or disengage the brakes.
The two chambers in the GDX Spring Brake Chamber are sealed with a double centre O-ring
in order to keep the air pressure levels separate. Keeping the air pressure levels separate is important
as it is the change in air pressure between the two chambers that engages or disengages the airbrake.
This powerful spring in the rear section has upwards of 2000 lbs of force!
That's about the same force as an elephant balancing on the top of a thumbtack.
With that is mind, you should never try to open this section without first securing it, as it could release,
resulting in a sudden, violent motion that can seriously harm you.
However, most spring brake chambers are permanently sealed in order to prevent these types of accidents.
If you ever need to service a spring brake chamber, regardless of whether it is sealed or not,
make sure to use a caging bolt to restrain the power spring and make it safe to handle.
Because of the design of a brake chamber, each has a limited pushrod stroke length capacity,
beyond which no brake force is produced.
The GDX Spring Brake Chamber has an orange stroke alert indicator to make this stroke reading easier,
but that doesn't replace a good slack adjuster! If you watched our video on Automatic Slack Adjusters
you already know that the airbrake system includes a slack adjuster that moves the position
of the brake chamber as the brake shoe is used.
When shopping around for brake chambers it's good to keep in mind that they are made in
a variety of styles, types and sizes, so it is important to correctly identify your brake
Brake chamber size can be determined by measuring
the diameter of the clamp used to hold it together, by locating the size markings on
the outside of the brake chamber, or by looking at your vehicle's owner manual.
The most common brake chamber size type is 30. However, there are vehicles using both smaller and larger sizes.
For example, type 16, 20, 24 and 36 brake chambers may also be used.
The type number refers to the area in square inches that the air acts on,
which identifies the amount of force that the chamber is capable of.
If your vehicle operates with a standard stroke,
look for spring brakes that have round boss air inlets.
However, if you need a spring brake with a long stroke, look for square boss inlets,
a larger center body, and the corresponding identification tags and markings.
Regular maintenance is also important as it will extend the life of your spring brakes
and save you money down the road. Here are some things to keep an eye out for when doing your regular inspection:
Look for any corrosion or rust on your brake. Make sure to look at the slack adjuster position
as it will help to indicate if the brakes are experiencing issues, for example
if your brake is only completing half of a full stroke,
that could be an indication of a broken power spring.
To get a better sense if the spring brake is broken, tap against the body of the brake and listen for rattling.
Also look carefully at the two mounting nuts that hold the chamber onto the axle. Any signs of uneven wear,
loose or missing nuts, or road damage will require immediate attention.
If you're mounting a spring brake for the first time, ensure it is in the proper position on your axle.
The chamber's pushrod, which connects the unit to the slack adjuster should be centered.
A misaligned pushrod could lead to premature wear, and eventual damage to the diaphragm.
The most common causes of misalignment are incorrect push rod length, or incorrect mounting.
Keep these maintenance tips in mind, since they can save you time and money in the long term,
and can even help to prevent any future brake failures.
Now you're up to speed with Spring Brake Chambers, but if you have any questions,
please don't hesitate to call us
or leave us a comment down below.
Or you can visit our website at greggdistributors.ca.
Again, I m Brady, and thanks for checking out Gear up with Gregg's.
Have a great Canadian day!