This tutorial is also available in French
➔
Brake system bleeding on Austin Mini (AM from 1988 onwards)
Vehicle ➔ Mini 1000 am1991 automatic
Difficulty ➔ Easy
Time ➔ 2 hours
Summary
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This tutorial only concerns Minis with master cylinder GMC90376 mounted from 1988. There is another tutorial that deals with this subject for Minis with master cylinder GMC227 mounted from 1980 to 1988
(➔ see the tutorial).
Used brake fluid is a hazardous product. It must not be thrown into the natural environment, into the sanitation system, or into household waste. Put the used brake fluid in a container and take the container to the recycling center.
Here are the 2 reasons why we should regularly change the brake fluid:
• Over time, brake fluid loses its anti-corrosive properties. The brake circuit is no longer protected and may rust.
• Over time, brake fluid absorbs moisture from the air and becomes saturated with water. Its boiling point is then reduced. During repeated braking, the brakes will heat up, and the brake fluid may boil and release gas. Since gas is compressible, the Mini will no longer brake.
• Over time, brake fluid loses its anti-corrosive properties. The brake circuit is no longer protected and may rust.
• Over time, brake fluid absorbs moisture from the air and becomes saturated with water. Its boiling point is then reduced. During repeated braking, the brakes will heat up, and the brake fluid may boil and release gas. Since gas is compressible, the Mini will no longer brake.
The capacity of the brake circuit is 0.35 L (for 850 and 1000 engines).
Brake fluid is extremely aggressive with paint. Be careful not to spill any on the bodywork. Clean any stains immediately with a cloth and water.
Always use new brake fluid. Never put used fluid back into the master cylinder reservoir.
It is not essential to remove the wheels of the Mini to bleed the brakes, but the bleed screws are much more accessible without the wheels.
The Eezibleed kit
The Eezibleed kit allows you to bleed your brakes alone. No need to buy the kit if you have a friend to help you. In this case, you can use the traditional method which consists of bleeding the brakes when your assistant presses the brake pedal.
The Eezibleed kit is supplied with compressed air by the spare wheel which you will need to deflate beforehand to a maximum of 1.4 bar. For my part, I preferred to deflate to 1 bar because at 1.4 bar I had a micro-leak at the level of the master cylinder reservoir cap.
The Eezibleed kit comes with several master cylinder reservoir caps. It can thus be used on almost all Minis. If none of the caps in the kit fit your Mini, you can always buy the appropriate cap, drill a 10 mm diameter hole in it and adapt the Eezibleed system to it.
The advantages of the Eezibleed kit:
• The brake fluid is pushed by compressed air. It is therefore unnecessary to press the brake pedal.
• The master cylinder reservoir never empties because it is automatically supplied with new brake fluid by the Eezibleed kit bottle. It is therefore unnecessary to constantly monitor the level of brake fluid in the master cylinder reservoir to prevent air from entering the hydraulic braking circuit.
• The brake fluid is pushed by compressed air. It is therefore unnecessary to press the brake pedal.
• The master cylinder reservoir never empties because it is automatically supplied with new brake fluid by the Eezibleed kit bottle. It is therefore unnecessary to constantly monitor the level of brake fluid in the master cylinder reservoir to prevent air from entering the hydraulic braking circuit.
Required Tools
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Packaging :
•
GRK6009: The master cylinder cap is sold individually.
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Install the Eezibleed kit
Op 01
Release the handbrake.
Op 02
Disconnect the 2 electrical wires from the brake fluid level sensor.
Op 03
Remove the cap from the master cylinder reservoir. Unscrew by hand.
Op 04
Select the Eezibleed kit cap adapted to the master cylinder reservoir of your Mini.
Check that it screws perfectly onto the master cylinder.
Op 05
Assemble the cap on the kit hose using the seals and nut provided with the Eezibleed kit. Use the 11 mm combination spanner.
Do not forget to position the seals on either side of the cap as indicated in the instructions.
Op 06
Hang the Eezibleed bottle near the master cylinder. Use the hook included in the kit.
Fit the cap on the master cylinder reservoir. Screw by hand.
Make sure that the cap seal is correctly positioned and flat.
Do not overtighten the cap on the master cylinder. Screw it until you feel the seal contacting the reservoir and tighten an additional 1/8th of a turn.
Op 07
Check the pressure of the spare wheel. Use the pressure gauge.
If necessary, deflate the wheel to reach a maximum of 1.4 bar.
Op 08
Connect the Eezibleed kit to the spare wheel.
Check that there are no air leaks at the master cylinder reservoir.
Gunson, the manufacturer of the Eezibleed kit, recommends a maximum pressure of 1.4 bar. I tested the circuit with this pressure and I had a micro leak at the level of the master cylinder reservoir cap. I therefore reduced the pressure to 1 bar, the leak disappeared and I was able to bleed my braking circuit.
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Drain the brake fluid
Op 09
Fit the bleed hose (included in the Eezibleed kit) in the used brake fluid recovery container.
Op 10
Remove the cap from the bleed screw of the front left wheel caliper. Use the flathead screwdriver.
The front left wheel is on our left when we are driving the vehicle.
Op 11
Fit the 11 mm combination spanner on the bleed screw. Do not loosen it for now.
Engage the bleed hose on the bleed screw. Push by hand.
Op 12
Unscrew the bleed screw by 1/4 turn. Use the 11 mm combination spanner.
Let the used brake fluid flow until the master cylinder reservoir is empty.
Retighten the bleed screw. Use the 11 mm combination spanner.
I drained the master cylinder reservoir through the front left wheel because it was more convenient for me, but it can be drained through any wheel.
Op 13
Disconnect the Eezibleed kit from the spare wheel.
Always disconnect the spare wheel before unscrewing the cap from the master cylinder or the cap from the bottle.
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Bleed the brake circuit
Op 14
Fill the master cylinder reservoir and the Eezibleed bottle with new DOT4 brake fluid.
Hang the Eezibleed bottle again and screw the cap onto the master cylinder.
Make sure that the bottle is almost in a vertical position and that the end of the plastic hose touches the bottom of the bottle.
Op 15
Connect the Eezibleed kit to the spare wheel again.
Op 16
Start bleeding with the rear left wheel (the wheel farthest from the master cylinder).
Remove the cap from the bleed screw. Use the flathead screwdriver.
On this Mini, the steering wheel is on the left but the master cylinder is positioned on the right of the vehicle. You must therefore start bleeding the brakes with the rear left wheel (the one farthest from the master cylinder).
Op 17
Fit the 8 mm combination spanner on the bleed screw. Do not loosen it for now.
Engage the bleed hose on the bleed screw. Push by hand.
Op 18
Unscrew the bleed screw by 1/4 turn. Use the 8 mm combination spanner.
Let the used brake fluid flow as long as there are air bubbles.
Retighten the bleed screw. Use the 8 mm combination spanner.
You will certainly notice a color difference between the used brake fluid (darker) and the new brake fluid (lighter). If this is the case, let it flow until the new brake fluid arrives.
Check regularly that there is always brake fluid in the Eezibleed bottle. Add more if necessary. You must absolutely prevent air from entering the hydraulic braking circuit.
Op 19
Disconnect the bleed hose. Pull by hand.
Remove the combination spanner.
Fit the bleed screw cap.
Op 20
Bleed the rear right wheel. Repeat the same operations as before.
Op 21
Bleed the front left wheel.
Op 22
Bleed the front right wheel.
Op 23
Disconnect the Eezibleed kit from the spare wheel.
Remove the cap from the Eezibleed kit. Unscrew by hand.
Before unscrewing the cap, position the bottle lower than the master cylinder (1st photo) and wait for the hose to empty into the bottle. This will prevent spilling the brake fluid contained in the hose.
Op 24
Top up the master cylinder reservoir. Add or remove DOT4 brake fluid if necessary.
The minimum and maximum levels are marked on the sides of the master cylinder reservoir (2nd photo).
Op 25
Fit the master cylinder reservoir cap (GRK6009). Screw by hand.
Connect the 2 wires of the brake fluid level sensor.
The 2 wires have no particular position. It doesn't matter in which order you connect them to the brake fluid level sensor.
When the bleeding operation is finished, always clean the elements of the Eezibleed kit (bottle, cap, hoses and seals) with brake cleaner. Over time, the brake fluid could attack the rubbers and plastics.
Op 26
Check that the brake pedal is firm. Press with your foot.
Op 27
Take a road test to verify that the braking system works perfectly.
The End
