D2 - air in the brake lines?

[twr7cx]

About 12 months ago I removed the factory rubber brake lines and replaced with Terrafirma stainless steel braided lines that are +2" longer. Manually bled the system and all has been fine.

Until a month ago when I drove into a gate. The brakes failed on me, I was pushing and pushing the pedal but the brakes just wouldn't bite and the car just didn't slow down (until it hit). They worked again afterwards, so I accepted that it was my poor judgment and driver error.
Yesterday, however, I was moving the D2a out of the drive way and it happened again (this time I was traveling much slower so nothing was hit thank fully)!

This morning I've had the wheels off and went around bleeding the brakes. They were fine until I got to the last one, the drivers side front. It was full of air (the cause of my lack of brakes)! 500ml of fluid later, bleeding with both the engine off and then on, it's not pushing out fluid with no air in it.

I'm going to leave it to sit for a while and then I will bleed it again to confirm.

Is there something else I need to do on the D2 because of the ABS or TC?

I have checked the whole system and can't find any evidence of leaks. The brake fluid level has not gone down since I last bled them about 12 months ago.

Ideas?

[walker]

I might be wrong, but I just had a feeling that you couldn't bleed D2 brakes yourself because of the ABS modulator, you had to have it professionally done. I am guessing it has to have so sort of positive pressure to bleed brakes.

[twr7cx]

I might be wrong, but I just had a feeling that you couldn't bleed D2 brakes yourself because of the ABS modulator, you had to have it professionally done. I am guessing it has to have so sort of positive pressure to bleed brakes.

From what I understand, you require Testbook to do it if you have replaced the ABS module or anything up the line from the ABS module. But down the line items such as brake hoses should be fine to manual bleed.

Rave outlines the manual bleeding procedure.

[Pedro_The_Swift]

Some say you need a nanocom to bleed them,
some say you can do it by tricking the ABS to operate, the so called powerbleed.
I have had two dead pedals, in two different D2's, both in exactly the same spot doing exactly the same thing. Start from cold, select gear, idle off to first T intersection. I put it down to lack of vacuum, so now I drive off and to hell with the neighbours;).

[Aaron40]

Having this exact problem atm and have not been able to push fluid out the front lines, it is in at Lifestyle 4wd atm and it has had all checked or replaced you may want to call Steve Armour as he has been going over and over the problem discussing it with other mechanics in Perth to try and come up with a remedy..(08) 9271 7900

[OffTrack]

The relay trick just runs the return pump which is effectively what a power bleed does. This won't address problems cause by air trapped in the modulator valving.

There is a full bleed procedure in the WABCO support documentation that can be roughly adapted to the Nanocom/Hawkeye.

I made a start sometime ago on Nanocomising the procedure.I haven't tested the process so feedback is welcome. I'm working on the theory that Land Rover would have followed WABCO tech advice on bleeding.

cheers
Paul

Brake Bleeding Procedure

The following brake bleeding methods explain
how to bleed a hydraulic ABS dry
modulator assembly during installation, or in the
event of air in the brake system. These instructions
are for manual bleeding with electronic diagnostic tool
and include the procedure for bleeding
both the master cylinder and the brake system. In
some cases, for example if you are replacing only
the modulator assembly, it may not be necessary
to bleed the master cylinder.

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.

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. (Note: you may be able to use the "test" function for each wheel for this step)

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.


NOTE: To perform a manual bleed, follow
Steps 2 through 8 under “Manual Bleed
Procedure (Wet Modulator Assembly)”


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.).

Wet Modulator Assembly Bleed



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.
Fill the reservoir with DOT-approved hydraulic
brake fluid.
Depress the brake pedal five times using the
stroke between 1/3 travel and maximum travel
in 5 seconds.
Release the pedal for 5 to 10 seconds. Air
bubbles will rise into the reservoir while
depressing and releasing pedal.
Repeat Steps 3 and 4 another three times, or
until sufficient pedal resistance is felt.

WARNING
Do not let the brake master cylinder fluid get
below the minimum level during the bleeding
operation. Keep the master cylinder reservoir
filled with new DOT-approved brake fluid as
specified by the original equipment manufacturer.
Failure to keep the brake reservoir level above
minimum could result in more air entering
system, making it impossible to effectively bleed
the system.
Bleed the brake system. Put a wrench on the
brake actuator bleeder fitting. Start with the
Passenger Front, then attach a length of clear plastic
tubing to the bleeder fitting. Make sure the
tube fits snugly.
Submerge the tubing in a container of clean
brake fluid.

NOTE: Both the tubing and container must be
able to withstand to the effects of brake fluid.
Depress the brake pedal 10 to 15 times, using
the maximum available stroke.
Loosen the bleeder fitting until the fluid begins
to flow, (about 3/4 turn), while depressing the
brake pedal through its maximum available
stroke.
Tighten the fitting firmly prior to releasing the
brake pedal.
Repeat Steps 6 through 8 several times until
the discharged fluid is free of air bubbles.
Repeat Steps 3 through 9 to bleed the
remaining three brake actuators. Bleed in
sequence Passenger Front, Driver Front, Passenger Rear, Driver Rear.
Check the travel of the brake pedal. If a firm
resistance is felt the manual bleeding
procedure is complete.
Check the fluid level in reservoir and fill if
required. Replace reservoir cap and dispose of
used brake fluid.
Remove wheel chocks.

[twr7cx]

Nanocom Evolution has the following under SLABS / UTILITY / ABS BLEEDING - TESTS:


POWER BLEED
MODULATOR BLEED
FRONT RIGHT TEST
FRONT LEFT TEST
REAR RIGHT TEST
REAR LEFT TEST


Struggling to find any instructions on their usage though.


EDIT: found the following:


Power Bleed.
This function allows to perform bleeding of the main circuit. It activates the pump for a few seconds and you must repeat the function until the oil reaches the brake. The same work can be done by pushing the brake pedal.

Modulator Bleed
Modulator bleed must be preformed with pipes closed, pushing the pedal with maximum strength during the function. Once function is preformed, release the pedal and repeat until the pedal stroke is normal.

So seems like Power Bleed is used on an empty system to get the fluid going through. I assume the pedal doesn't need to be pressed.

Modulator Bleed requires the pedal to be pressed.

But unsure on the tests. Do they need the pedal to be pressed?




EDIT AGAIN:


FRONT RIGHT TEST - FRONT LEFT TEST - REAR RIGHT TEST - REAR LEFT TEST
This function activates the modulation of the brake on the desired wheel. During the function if you turn the wheel by hand, you can see that it is blocked several times for few seconds.

http://cdbl.free.fr/Nanocom/V1-V2/Manuels/Anglais/DIAGNOSTIC%20FUNCTIONS%20OF%20THE%20ABS-SLS%20SLABS%20DiscoveryII.pdf

[OffTrack]

Struggling to find any instructions on their usage though.


The procedure I posted above is pretty close to what Testbook steps you through as far as I can tell. The best information I'd found was a really sketchy description by a guy who had helped a mechanic do the testbook routine. The WABCO bleed docs seem to match up in general long windedness and the need for repeated bleeding.

The basic approach of modulator bleed with pedal depressed, pedal up for 5 seconds, power bleed, then repeat 3 times will force any air in the system to the calipers. Followed by a manual bleed it should work well enough.

cheers
Paul

[twr7cx]

I have discovered something strange. There seems to be an almost continuous leak of air through the right front (drivers side) caliper bleed nipple. With the nipple shut and a hose attached full of fluid, are bubble continue to come through (no fluid does though).

I checked the hose fitting and it's tight. Tried it on the other three calipers and they don't do it.

So I removed the bleed nipple and cleaned the seat in the caliper. Refitted and same deal.

Removed a bleed nipple from a 1994 Ford EF Falcon GLi station wagon and fitted this and that stopped the leak.

No air is coming out when bleeding any of the four wheels. Have run the power bleed, modulator bleed and tests using Nanocom Evolution numerous times as per the instructions above.

Strange.

[twr7cx]

I have had two dead pedals, in two different D2's, both in exactly the same spot doing exactly the same thing. Start from cold, select gear, idle off to first T intersection. I put it down to lack of vacuum, so now I drive off and to hell with the neighbours;).

Arn't you vehicles petrol V8's? If so, they should have vacum at idle, so reving the engine up (which I assume is what you mean by:
so now I drive off and to hell with the neighbours;).) won't create any more vacum. The wider you open the throttle, the less vacum there would be...

[twr7cx]

Picture of my leaking (dissappearing )nipple:




Ooooops! Wrong nipple...


https://www.aulro.com/afvb/images/imported/2013/03/292.jpg

Hard to see from the picture (if I took the picture any closer it just comes out a blur), but on the tapered end of the bleed nipple, there is a flat spot all the way around about 0.5mm wide - I don't think this is mean to be there, might have been caused by over tightening or something.

[Ten]

Occasionally I have had the same experience with my petrol D2. The first brake application in the morning fails to slow the vehicle.

It doesn't feel like air in the system as pumping the pedal makes no difference - just a hard pedal. I have thought it could be a leak in the brake servo and have let it idle for a while before starting off, but more recently I feel that it could be the pads not warmed up. Always after travelling a short distance the brakes are fine. Air in the system would give a spongy pedal all the time I would think?

Ten.

[schuy1]

yep, thats a result of over tightening. The nipple face should be a taper with no grooves or scratches in it. The seat and taper seal on a very fine line and should be just above finger tight in my world :D
Cheers Scott

[twr7cx]

yep, thats a result of over tightening. The nipple face should be a taper with no grooves or scratches in it. The seat and taper seal on a very fine line and should be just above finger tight in my world :D
Cheers Scott

Do you know what the nipples are made out of? Are they a softer material than the calipers? I'm wondering if the seat in the calipers is also likely to be damaged (assume they're not too bad though as they're not leaking with the temporary Falcon bleed nipple fitted).

[schuy1]

Generally the seat in the caliper is ok, it is the nipple that deforms. So yes the nipple is most likely softer. And it is surprising in this day and age of manufactuers making each their own, that bleed nipples are for the most part surprisingly interchangeable. To do with there only being a few brake manufacturers I assume .

Cheers Scott

[Pedro_The_Swift]

Arn't you vehicles petrol V8's? If so, they should have vacum at idle, so reving the engine up (which I assume is what you mean by: ) won't create any more vacum. The wider you open the throttle, the less vacum there would be...

damn,, there goes my excuse--

[frostyblue]

Hey guys, got same sort of issue with my brakes, jumping on them abs works fine, its when maybe coming to a set of lights that change quickly, you press pedal and they are rock hard you can push as hard as you like but it still stops slowly, it almost feels like if you rolled the car turned off eg lack of power assistance, is there anyway of checking vaccum, booster etc, i did remove hose and there is plenty of suction, failing that any recomends on a brake speciliast in brissy, any other ideas or checks i can do

Cheers

Ken

[d2dave]

Ken, If you have plenty of vacuum it sounds like a problem with you booster.

[SiddersC]

Simple check of the boster.

After shutting down the engine, step on the brake pedal a few times, there should be vacuum present in the chamber, so you should feel the pedal get harder, 2 - 3 strokes should have exhausted the vacuum and pedal will be hard.

If it is hard straight away, booster (or 1 way valve) is suspect as you have already ruled out the vacuum supply

You can also test it by pressing hard on the brakes with the engine off, keeping pressure on the pedal start the engine and you should feel the pedal fall away slightly.

[SPROVER]

Today I replaced the rear discs and pads on my D2. When I started the car to test the brake pedal pressure it just went down pretty much to the floor. When I did the front discs and pads a few months ago I never had this problem. I have read so many different ways to bleed the system and it has got me no where:D.

What I would like to know is, can I just do the old fashioned bleed of the brakes? From rear to front with the jar and a clear line? I didn't get any air in the system that I know of. All I did was remove the caliper, change the disc and push the piston in the caliper so I could fit the new pads.

There seems to be so many conflicting ways of doing it. Any help would be great.

Thanks

Chris

[d2dave]

Chris. Did you pump the pedal a couple of times to bring the pads to the disc?

It is quite normal for the first one, maybe two pedal pumps to go to the floor after changing pads. There is no way air can enter the system doing what you have described.

As for bleeding, yes they can be bled the same as any old type brake system providing air has not entered into the ABS pump and this would not happen if you were only opening the system at a wheel, eg. changing a flexible brake hose.

The only difference with the D2 is if doing a brake fluid change. You can still do this the same as an old car except you will not get the fluid in the ABS pump changed.

[SPROVER]

Chris. Did you pump the pedal a couple of times to bring the pads to the disc?

It is quite normal for the first one, maybe two pedal pumps to go to the floor after changing pads. There is no way air can enter the system doing what you have described.

As for bleeding, yes they can be bled the same as any old type brake system providing air has not entered into the ABS pump and this would not happen if you were only opening the system at a wheel, eg. changing a flexible brake hose.

The only difference with the D2 is if doing a brake fluid change. You can still do this the same as an old car except you will not get the fluid in the ABS pump changed.

Thanks Dave. A few quick pumps :D And she was all good again.:p I was in a rush yesterday fitting them up under the carport and completely forgot to pump the brakes a few times before I started it.

[d2dave]

If you ever watch Bathurst you will here the guy on the radio reminding drivers to pump the pedal a few times as they are leaving pits after a pad change.

I remember a few years ago a driver forgot to do it. Arrived at his first corner and drove straight into the wall.

If memory serves me correct it was Russel Ingal but don't hold me to that.