Why Does a Brake Chamber Need to Be Caged?
Caging a brake chamber is a critical safety step that protects technicians from injury and ensures controlled service conditions. Spring brake chambers contain powerful internal springs that must be mechanically restrained to prevent sudden release during service. Before servicing the air brake system or moving a disabled vehicle with no air pressure, caging the brake chamber is necessary. By manually compressing the spring, this procedure temporarily deactivates the brake – allowing safe inspection, handling or towing without the risk of unintended brake engagement.
Before Starting to Cage Your Brakes
- Wear Protective Gear
Always wear safety glasses to guard against accidental spring release. - Block the Wheels
Securely chock the wheels to prevent unintended movement. - Check for Damage
Check the chamber for cracks, corrosion, or other defects. Do not attempt to cage a damaged unit.
Steps for Caging Brakes

Locate the caging bolt that is stored on the chamber. Remove it and ensure it’s clean and the threads are in good condition.


To insert the bolt, first remove the weather seal. Place the bolt into the chamber, guiding the locking tabs into the end of the center shaft and lock it in place by turning one quarter turn.


After locking the bolt in place, install the washer and nut. Failure to use a washer can result in the nut pulling through the chamber housing.


Using a brake chamber caging socket, begin tightening the nut using a ratchet. Tip: Never use an air wrench, this procedure must be performed manually to avoid collapsing the chamber.


As you compress the spring, tension will increase. Once it bottoms out, you’ll know it’s fully collapsed. The brake is now caged and it is safe to either move the vehicle or service the brakes.
Important Notes:
- Caging Bolt as Indicator
A caging bolt shows that the brake has been manually disabled. Always confirm its presence before proceeding. - Safety First
Never assume a spring brake chamber is safe. Always cage a brake chamber before handling. - Emergency Use Only
Caging is intended strictly for emergency or repair purposes. Do not operate a vehicle with caged brakes under normal driving conditions.
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The content in this article is for informational purposes only. You should consult with a certified technician or mechanic if you have questions relating to any of the topics covered herein. DRiV and its affiliates (including Federal-Mogul Motorparts LLC) will not be liable for any loss or damage caused by your reliance on any content.