Like drum brakes, spring brakes are subject to regular maintenance, to keep them in working condition. Spring brakes are available in vehicles with air brakes. The brake in such a vehicle is implemented and retracted by spring and air pressure respectively. Spring brakes are totally opposite to service brakes. Both, however, use the same linkage and chambers, to ensure a spring brake system is in good condition.
The main purpose of spring brakes is parking – in case of an air pressure lost, they help stop the vehicle. Spring brakes removal is a cumbersome process; so you should not try it unless you have the relevant knowledge and experience.
- Tools and Materials
- Wheel blocks
- Caging wrench
#1: Access the Caging Bolt
The caging bolt runs through the service brake chambers and spring brakes. To compress the spring, you need to turn it first. You should not proceed to disassembling the spring since it remains under high pressure. The methods to reach to the bolt could be different, depending on the air brake system. Most of the times you may have to remove the dust boot. In some other systems it may take you to remove the lock plate. Before proceeding, check the air brake manual.
#2: Block the Wheels
First put some blocks under each wheel. As the rig losses air pressure, you need to cage the spring. Releasing the parking is a must before towing the vehicle.
#3: Cage the Bolt
You can find the instruction for caging the bolt on the body of parking brake chamber. Abide by the instructions to avoid injuring yourself. Once you have compressed the bolt by compressing, start disassembling the chamber to replace the spring.
Assign a technician with prior experience to disassemble the brake chamber. The pressure level on the spring is probably thousands of pounds or more, making it lethal if released suddenly. Right after caging the bolt, the parking brake is released and the rig is ready to be towed. At this point, you should let the technician do the job; unless you have prior training of disassembling the brake chambers.
On an air brake system, replacing a spring parking brake is quite difficult, because only a professional can approach this. Follow the instructions on the chamber for compressing or caging the spring by tightening the caging bolt. Replacing the spring is however a job better be done by a professional.