Bleeding Process 1968-74 MGB, 1968-on Sprite/Midget
Preparation
Absolute cleanliness must be maintained throughout the entire bleeding operation, ensure that no dirt or grit enters the system. All equipment to be used must be free from fuel, paraffin, or any form of mineral oil.
1. Check that all connections are tight and that the bleed screws are closed.
2. Release the hand brake.
3. Top up the master cylinder with a recommended brake fluid. CAUTION
a. Never re-use brake fluid which has been bled from the system.
b. Keep brake fluid away from all paintwork
c. Do not allow the fluid level to fall so low that air can enter the system during bleeding; always top up the level
Bleeding
4. Attach bleeder tubes to the bleed screw on the R.H. front and R.H. rear brakes and submerge the free end of each tube in a small quantity of brake fluid in a clean glass jar.
5. Open the bleed screws about half a turn.
6. Commence bleeding with very light strokes of the pedal. DO NOT push the pedal through it’s entire stroke. DO NOT test the pedal until all the air has been expelled from the system and the system fully bled. If during the bleeding operation the warning light should glow continue bleeding until all the air is expelled from the system.
7. Repeat procedure 6 until the fluid flowing into each glass jar is free of air bubbles and then close the bleed screws during the next (last) pedal application. Top up the reservoir after tightening the bleed screws.
8. Bleed the L.H. front and L.H. rear brakes in the manner described in procedures 4 to 7.
9. If the warning light glows attach a bleed tube to the L.H. rear brake (see procedure 4). Open the bleed screw half a turn and slowly depress the brake pedal, immediately the light goes out release the brake pedal and tighten the bleed screw. If the light fails to go out transfer the bleed tube to the R.H. front brake (see procedure 4). Slowly depress the brake pedal, immediately the light goes out release the brake pedal and tighten the bleed screw.
Stop light switch adjustment.
A free movement of 1/8 in. (3.2 mm) measured at pedal pad must be maintained on the brake pedal.
To adjust the free movement, slacken the stop light switch locknut and turn the switch clockwise to decrease or anti-clockwise to increase the clearance. Tighten the stop light switch locknut.