Expelling air from the braking system of a loader is a crucial step in maintaining braking performance. If air gets mixed into the system, it can lead to soft braking, extended braking distance, or even failure. The following are the specific operation procedures and precautions:
1,Preparations before Exhaust
Tools and Materials
Brake fluid that meets the specifications (such as DOT3/DOT4, which must be consistent with the original vehicle).
Transparent plastic hoses and glass bottles (for collecting the discharged brake fluid and gas).
Wrench (for loosening the brake caliper exhaust screw).
Jacks and safety brackets (to ensure the vehicle is stationary on a flat ground).
Check the brake fluid level
Open the engine hood and check the fluid level of the brake master cylinder (hydraulic brake pump). If it is lower than the MIN line, it needs to be replenished to the MAX line.
Note: Brake fluid is corrosive. Avoid contact with skin or paint surfaces.
2, Exhaust Operation Steps
When starting the exhaust sequence, the braking system of a loader usually has multiple brake calipers (such as the front axle, rear axle, steering axle, etc.). The exhaust should be carried out according to the "from far to near" principle, that is, the caliper farthest from the brake master cylinder should be discharged first. For example:
Rear axle brake caliper → Front axle brake caliper → steering axle brake caliper (please refer to the model manual for details).
Single-pump exhaust flow
Step 1: Place one end of the transparent hose over the brake caliper exhaust screw and immerse the other end in a glass bottle containing a small amount of brake fluid.
Step 2: One person slowly steps on the brake pedal 3 to 5 times, keeping the pedal in the depressed state. Another person loosens the exhaust screw by 1/2 to 1 turn with a wrench. At this point, the brake fluid mixture gas will be discharged through the hose.
Step 3: Observe the bubble condition in the glass bottle. When all the bubbles have completely disappeared and the discharged fluid is pure brake fluid, tighten the exhaust screw.
Step 4: Repeat the above operation until the exhaust of each sub-pump is completed.
Check and replenish the brake fluid
During the exhaust process, the fluid level of the brake master cylinder should be frequently checked to prevent air intake due to low fluid level.
After the exhaust is completed, replenish the brake fluid to the MAX line.
3, Verification and Closure
Braking test
Start the loader, gently press the brake pedal to check if the response is sensitive. If there is still a soft feeling, re-exhaust is needed.
The driving test (at low speed) confirmed that the braking effect was normal.
Cleaning and recording
Clean up the leaked brake fluid to prevent environmental pollution.
Record the exhaust date and the replacement status of the brake fluid to facilitate subsequent maintenance.
4, Precautions
Safety first: Protective gloves must be worn during operation to prevent brake fluid from coming into contact with eyes or skin.
Avoid mixing brake fluids: Different models of brake fluids have different chemical compositions. Mixing them may lead to brake failure.
Regular maintenance: It is recommended to replace the brake fluid every 1-2 years or as required by the user manual to prevent water from entering and causing a decrease in boiling point.
If the braking problem persists after exhaust, it might be due to aging of the seals on the master cylinder and slave cylinders or pipeline leakage, which requires further inspection and repair.
