Two Brake callipers not bleeding the entire brake pedal stroke - faulty ABS units?

Yesterday afternoon I took the car out the back of our property and did some brake tests on the gravel/dirt tracks from around 60km/h. It pulled up well and the tracks left in the gravel/dirt indicated all were braking.
I then did a road test and it drove fine under normal driving conditions.

26km trip to work this morning, mainly highway with little braking. Drove fine until the last 6km. Coming up to a red light intersection from approx 45km/h, apply the brakes, firm pedal but the cars not slowing down, then suddenly it starts to slow down, the steering jerks left (does this indicate which wheels brakes are being applied?) and a wheel lock up skid is heard before ABS unlocks.
For the rest of the trip the brakes were like this. I tested on the road a few times and the same thing - firm hard brake pedal, steering jerks left hard and even at such slow speeds and without the pedal being pushed that hard a wheel is locking up and squeeling before the ABS kicks in and unlocks.

Was that with new master cylinder ? if not wait untill the new one is fitted then you'll see

What rotors/pads are you running?
I found that the factory standard pads rotors to be sub standard on my D2a to the DBA slotted rotors and heavey duty pads i fitted last year.[thumbsupbig]

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Originally Posted by sierrafery

Was that with new master cylinder ? if not wait untill the new one is fitted then you'll see

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Nope. Have ordered a new master cylinder this morning when I arrived at work. Car will be grounded now until it's arrival then after this mornings experience.

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Originally Posted by trout1105

What rotors/pads are you running?

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I'm running EBC Yellowstuff brake pads and RDA dimpled/slotted rotors. It's the best brake combination I've had during my 10 year/120,000km ownership of the vehicle.
Regardless the brake pads and rotors aren't going to effect the caliper bleeding and are unlikely to cause the violent left pull on brake application.

would be a good idea to change out the other brake lines as well , definitely hydraulic problem . I have seen internal brake line delaminate ( not land rover ) cause this issue as the pressure builds up then lets go

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Originally Posted by discorevy

would be a good idea to change out the other brake lines as well , definitely hydraulic problem .

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The set of flexi brake lines currently on are a braided set that were fitted not that long ago. The one that was damaged was I believe due to my fault not having set the lengths properly in the support brackets causing it to be pulled on when at full lock one way.

Replaced the master cylinder with a genuine OEM TRW unit. The bleeding issue is recolved. They all bleed properly now. But, I have a slowly sinking pedal issue now! Only occurs when the engine is running, doesn't happen with car off. If you have your foot applying the brakes (like you would when waiting at an intersection), the pedal slowly sinks down until it gets to about 3/4 of the travel. Does this indicate an issue/failure of the internal seals on the new master cylinder unit? Wondering if I can block up the two outlet ports of the new master cylinder to see if it still occurs to indicate if that's the faulty part.

In installing the new master cylinder, I:
took a brake pad out of each brake calliper.
Applied the brakes a few times to fill the callipers up with additional brake fluid.
Swapped the master cylinders over and filled up the brake fluid.
Pushed the caliber pistons bake to backfill the new master cylinder and bleed air up.
Carried out the following bleeding process:

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Manual Bleed Procedure with Electronic Diagnostic Tools

NOTE: The electronic diagnostic tool must be capable of actuating (energizing) the outlet solenoid valves for each wheel for approximately 10 seconds and activating the pump of the modulator. The inlet solenoid valve should be open (de-energized). Both Nanocom and Hawkeye diagnostic tools can be used to do this.


1. Apply the parking brake and chock the tires. Turn the ignition OFF.
NOTE: The ignition must remain off for the initial bleed procedure; energizing the unit during bleeding must be impossible.

2. Perform brake bleed procedure for wet module, bleeding the circuit and master cylinder if required prior to connecting diagnostic equipment:

Manual Bleed Procedure (Wet Modulator Assembly)

a. Apply the parking brake and chock the tires. Turn the ignition OFF and disconnect the battery terminals.
NOTE: The ignition must remain off for the entire bleed procedure; energizing the unit during bleeding must be impossible.

b. Fill the reservoir with DOT-approved hydraulic brake fluid.

c. Depress the brake pedal five times using the stroke between 1/3 travel and maximum travel in 5 seconds.

d. Release the pedal for 5 to 10 seconds. Air bubbles will rise into the reservoir while depressing and releasing pedal.

e. Repeat Steps c and d another three times, or until sufficient pedal resistance is felt.

f. Bleed the brake system. Put a wrench on the brake actuator bleeder fitting. Start with the farthest from the modulator, (typically the right rear), then attach a length of clear plastic tubing to the bleeder fitting. Make sure the tube fits snugly.

g. Submerge the tubing in a container of clean brake fluid. Figure 7.
NOTE: Both the tubing and container must be able to withstand to the effects of brake fluid.

h. Depress the brake pedal 10 to 15 times, using the maximum available stroke.

i. Loosen the bleeder fitting until the fluid begins to flow, (about 3/4 turn), while depressing the brake pedal through its maximum available stroke.

j. Tighten the fitting firmly prior to releasing the brake pedal.

k. Repeat Steps 6 through 8 several times until the discharged fluid is free of air bubbles.

l. Repeat Steps 3 through 9 to bleed the remaining three brake actuators. Bleed in sequence of the longest to the shortest circuit from the modulator.

m. Check the travel of the brake pedal. If a firm resistance is felt the manual bleeding procedure is complete.

n. Check the fluid level in reservoir and fill if required. Replace reservoir cap and dispose of used brake fluid.

o. Remove wheel chocks

3. Connect diagnostic equipment to OBDII port.

4. Turn ignition switch ON

5. Push on brake pedal with maximum force (firm pedal) and hold.

6. Activate the Modulator Bleed function on the diagnostic tool starting with Passenger Front.

7. Release brake pedal for 5 seconds and run the Power Bleed function for approximately 5 seconds.

8. Repeat Steps 5 through 7 three additional times.

9. Perform manual bleed on appropriate wheels.

10. Repeat Steps 5 through 9 for the remaining 3 brake actuators, working in order of Drivers Front, Passenger Rear, Drivers Rear.


NOTE: If a firm brake pedal resistance is felt and the brake pedal pushes back when the solenoids and pump are simultaneously actuated for each brake circuit, the system bleed procedure is complete. If there is no firm pedal resistance, repeat the bleed procedure and/or look into brake system defect, (leaks, etc.).

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Slowly sinking pedal sounds like a crook master cylinder. Unless you can find an external leak somewhere else like maybe a loose bleed nipple.

Regards PhilipA

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Originally Posted by twr7cx

...Only occurs when the engine is running, doesn't happen with car off. If you have your foot applying the brakes (like you would when waiting at an intersection), the pedal slowly sinks down until it gets to about 3/4 of the travel. ...

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No worries as long as the pedal stops after a short travel, that's how it works. I remember that i was concerned too about that behaviour after i changed the master on mine 2 years ago. I digged deep to study the system and IMO it's normal cos once you start the engine the servo kicks in so more power in the pedal so it sinks a bit untill the air is fully compressed in the modulator's expansion chambers(10) and dampers chambers(6), there is air in these two parts on purpose which is not subject of the bleed procedure(parts nr 6 anf 10 in the picture), read the modulator's descriptionin RAVE, the gist is this: : "An expansion chamber is connected to each circuit to absorb pressure."
... went out now to check again and mine does the same(i presume they all should do that unless the expansion chambers or dampers are leaking)

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Originally Posted by PhilipA

Unless you can find an external leak somewhere else like maybe a loose bleed nipple.

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Not a single drop of fluid anywhere that it shouldn't be! Checked numerous times now. All the bleed nipples are torqued up.