Stage 1

A. Grease the camshaft spline.

B. Check that the brake chamber push rod is in its fully released position. With spring brakes, a minimum pressure of 6 bar is required in the system to ensure that the piston is fully released.

C. The new slotted anchor bracket supplied with the Automatic Slack Adjuster (ASA) should be fitted to the existing camshaft support bracket but not tightened.

Please note that different brackets, which may be handed, are used with different axles. The MEI ASA is supplied with the appropriate bracket.

Stage 2

D.Fit the ASA onto the camshaft, so that the arrow on the housing points in the direction of the application of the ASA, and the control arm end mates with the anchor bracket.

E. Wind the ASA into the clevis on the brake chamber piston rod by rotating the hexagon on the ASA in a clockwise direction until the hole in the ASA coincides with the holes in the clevis.

F. Fit the clevis pin into the clevis, through the ASA and secure. The pin should rotate freely when no load is applied.

Stage 3

G. Rotate the control arm as far as possible, following the direction of the arrow cast on the ASA body. Do not hammer the control arm.

The indicator A on the control arm should now be aligned with notch B in the cover plate.

H. Without moving the position of the control arm, fix the anchor bracket in place by tightening the mounting bolts.

Stage 4

I. Adjust the clearance by rotating the hexagon on the ASA clockwise (1) until the brake lining touches the brake drum, then back-off by rotating the hexagon a 3/4 turn anti-clockwise (2). Backing-off produces a loud clicking noise.

J. Fit the lining wear indicator C in a vertical position.

K. Secure the ASA on the camshaft ensuring it is not pinched or restricted.

L. Check that the ASA is functioning by applying the brakes a few times. The ASA is working when the hexagon rotates clockwise on the return stroke.

Maintenance

The ASA should be lubricated every 6,000 miles (10,000 km).

Once a year it should be checked as follows:

With a torque wrench on the hexagon nut on the ASA, turn it anti-clockwise and confirm that the mechanism does not slip at a torque of less than 18Nm. Repeat the exercise three times. If the mechanism does slip at a lower torque replace the ASA.

No attempt should be made to repair the ASA.