Good morning,just wondering do really need to run the ABS when bleeding? i recently bleed my brakes the old fashion way pumping the foot pedal until fresh fluid came through,should i have ran the ABS? my brakes seem to be fine.thank you. jamie...
Just bled my brakes today and thought I would put together a little how to for those that have not done this yet.
Tools required:
10mm spanner, large syringe, special cable, plastic bowl, small water bottle and bleed hose.
The cable is made up of 7 metres of twin core flex, an old toggle switch and two spade terminals. This will allow you to cycle the ABS modulator and easily bleed the brakes on your own.
A few tips to remember before starting:
– Brake fluid is extremely corrosive so wear rubber gloves and try to minimise spillage.
– Bleed the brakes in the order listed below (LHF,RHF, LHR & RHR)
– Make sure that the reservoir never runs out of fluid, keep topping it up with fresh fluid after each wheel bleed.
Step1: Remove the ABS relay from the under bonnet fusebox.
Step 2: Connect the spade terminals from the switch cable as shown.
Step 3: Remove the brake fluid reservoir cap and the filter. Using the syringe, drain the brake fluid reservoir. Once empty, fill to the brim with fresh brake fluid (leave the cap off).
The bleed screws are located on the top rear of the brake callipers.
Step 4: Jack up Left Hand Front wheel and place a bowl under the wheel, directly below the bleed screw (I do this to avoid the messy clean up afterwards). Place an axle stand underneath the axle for safety.
Step 5: Remove the bleed screw cap, connect the bleed hose and undo the bleed screw with the 10 mm spanner. Flick the toggle switch to the ON position and the ABS modulator will start to run. Run the modulator until the fluid coming out is clear – tighten the bleed screw and switch off the modulator. Replace the bleed screw cap and clean up any spillage.
Top up the reservoir with brake fluid and repeat Steps 4 & 5 for the Right Hand Front wheel.
Top up the reservoir with brake fluid and repeat Steps 4 & 5 for the Left Hand Rear wheel.
Top up the reservoir with brake fluid and repeat Steps 4 & 5 for the Right Hand Frontwheel.
You have just bled your brakes on your own and easily.
Good morning,just wondering do really need to run the ABS when bleeding? i recently bleed my brakes the old fashion way pumping the foot pedal until fresh fluid came through,should i have ran the ABS? my brakes seem to be fine.thank you. jamie...
Does ignition have to be on? Is the bleeder hose special or generic?
Thanks,
Warwick
Warwick,
From memory, ignition was off. If connections are solid and modulator won't run, turn ignition on but I'm pretty sure it was off.
No special bleed hose - clear tube with a short black rubber piece on one end (to connect to the bleed screw) and a metal weighted end on the other that goes into the bottle.
Cheers,
Franz
Franz,
Nice tutorial, but I have to point out both parts of above statement are wrong.
First, by bridging the relay you are running the the modulator return pump. This pumps fluid through the modulator but does not activate any of the valves.
Second, the shuttle valves operate as a result of pressure created in the brake fluid when you press the brake pedal, not control by the ecu of any other electronic device. The movement of the shuttle valve is used to signal to the SLABS ECU that the brakes have been activated. So in reality the SVS is exercised every time you push the brake pedal.. The idea that you need to exercise the Shuttle Valves by running the ABS/HDC is a complete nonsense.
If you want to make sure the modulator is bled, to a full bleed as described, then find a quiet street. Put the TC into low and turn on HDC. Accelerate up to 20kmh then take your foot of the throttle and let HDC slow down to 7kmh. Repeat the accelerate/HDC cycle 5-6 times or until you have run the Modulator for a minute or so. You can do this on the flat - no hill required. Then bleed the brakes again.
Cheers
Paul
There are 2 other ways to bleed the brakes solo on any car but also on a D2.
I use a MITYVAC vacuum pump . You just sit at the applicable wheel and pump away until you get fresh fluid . I try to get different coloured fluid if flushing. I find this way clean and efficient although a bit hard on the hand.
I also have a pressure bleeder which I haven't used yet as true to form LR changed the master cylinder arrangement from the previous standard European to where a special adaptor is needed to clamp over the master cylinder. I now have the adaptor so next time will use a pressue bleeder.
While neither of these methods clear the shuttle valves , after fitting new discs and pads and pushing the new/old fluid back to the master cylinder I now have a perfect pedal, just like my old RRC.
Regards Philip A
Not sure if this will help demystify the bleed process or not...
When the ignition is switched on the modulator valves are set to the default state - inlet valves are open and outlet valves are closed. Pressing the brake pedal causes the Shuttle Valve to close and brake fluid flows through circuit A then passes out the open inlet valve (12). Using the traditional pump and bleed method with the ignition switched on means that none of the fluid in circuit B or the return pump is bled.
When you run the modulator return pump the shuttle valve remains in it's unpressurised state and fluid is drawn around circuit B, then pumped into circuit A. The outlet valves remain closed so fluid between these valves (11), the expansion chambers (10) and the first non return valve (9) at circuit B is not replaced.
If you use a vacuum pump as suggested by Philip and have power removed from the modulator solenoid valves - which I suspect might require unplugging the harness from the modulator - the inlet and outlet valves should be open. Fluid will be drawn through circuit a, and circuit b. The non-return will limit prevent fluid flowing back through the outlet valves so it doesn't significantly improve bleeding in this section of the modulator. It should give a marginally better bleed than running the modulator pump, but still has a few "dead zones".
The HDC cycle I suggested earlier activates the pump and outlet valves to recirculates brake fluid through the portions of the modulator that aren't fully bled by the other methods.
The Nanocom has bleed functions that allow you to replicate a full WABCO bleed procedure (which also includes a manual bleed with power disconnected from the modulator - see below for fluid flow) but this will require two people and 30-60 minutes to complete. The WABCO procedure which seems very close to descriptions I've read of the Testbook bleed uses three different methods of moving fluid through the braking system and provides the most thorough bleed.
cheers
Paul
Paul,
Do you have any idea how much fluid id required for a full bleed?
Cheers,
Franz
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