Function

 

 Operation

 

Identification

 

Fitting

 

Maintenance

 

Warranty

 

Installation instructions are common to ASA (Automatic Slack Adjusters) and S-ASA (Self-Setting Automatic Slack Adjusters).

Do not use air wrenches or hammers. Their use will damage the product, prevent correct function and will void the warranty. 

Text in green is offered as advice.

If you have any questions about the fitting instructions, or require further advice, please email technical@meibrakes.com.

1. Ensure the vehicle is securely chocked before releasing the parking brake. Cage the spring brake or use a minimum hold off pressure of 90 psi (6 bar).

2. Remove the old slack adjuster, clevis pin, washer and split pins. Replace used parts with the new ones provided.

2a. Always replace Peg Bolt with the new one provided.

2b. Inspect Anchor Pins and replace if worn or damaged.

2c. Always replace Anchor Bracket with the new one provided. 

3. Clean and grease cam splines. Fit the anchor point by hand prior to final set up. 

4. Slide the slack adjuster on to the cam spline, locating the control arm in the anchor point at the same time. 

‘The adjuster only works in the direction of the cast arrow on the housing’

5. Using a socket wrench wind in the adjuster so that the clevis hole on the adjuster lines up with the clevis on the actuator. 

‘Do not pull the push rod to fit the pin. If required, de-adjust and start again, ensuring the clevis hole and clevis line up’

6. Grease the clevis pin before fitting. The clevis pin should slide into the holes without effort. 

‘If necessary, slacken off the lock nut on the clevis to achieve an easy fit and re-tighten afterwards’

7a. Fit wear indicator and return spring where present. Fit shim washers to ensure the gap prescribed. When fitting Peg Bolts ensure they protrude through the control arm grommet and tighten as prescribed.

 

7b. Replace cam bearings where there is excessive movement – the maximum allowable is 0.5mm. 

‘More movement will weaken the control arm or anchor points, disabling the adjustment’

7c. The control arm should always locate fully in the anchor bracket slot.

8i. When installing S-ASA the control arm and anchor point must allow free and full articulation of the adjuster.

‘Incorrect installation can lead to clashing with surrounding chassis or components’

8ii. When installing ASA the control arm and anchor point must be set in the correct position, as indicated by the arrow on the control arm. This is in the same rotational direction as the arrow on the housing.

‘This ensures the correct running clearance is maintained by the ASA’

On some ASA a setting indicator and notch on the control plate are provided as a visual aid. The setting indictor should line up with the notch when correctly installed.

9i. Once the installation is complete, anchor points should be tightened using the prescribed torque.

9ii. Control arm must not be bent during tightening of the anchor pin. 

‘There should be no stress on any fixing point or clevis. Stress on the anchor points can cause fatigue and eventual fracture, disabling correct function’

10. Manually adjust the brake by putting a socket wrench on to the hex nut and turning until the brake linings touch the brake drum.

11. De-adjust the brake by turning the socket wrench in the opposite direction by ¾ of a turn. 

‘You should hear a clicking noise’

12. Apply and release the service brake. The hexagon should index clockwise on the release stroke. 

‘This allows the brake drum to rotate freely’

13. The function test now complete, re-set the brake by putting a socket wrench on to the hex nut and turning until the brake linings touch the brake drum.

14. De-adjust the brake by turning the socket wrench in the opposite direction by ½ a turn.

‘This allows the brake drum to rotate freely’

15. Uncage the spring brake and apply the parking brake prior to removing the chocks from the vehicle. 

  

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