Thread: Hill Desent

Engage low range, drive down the street about 20kph, release throttle and HDC should activate and slow you down

Tried that. I can hear the pump working but it did not slow me down.

If you can hear the pump working I would say all is ok?
You may not have enough momentum to feel the full effects

HDC should slow you down in a fairly obvious way. Depending on which gear you are in target speed is 5-9kph with no throttle. Braking becomes more aggressive the closer you get to the target speed, but will cease once you get below it.

You can use throttle to modulate the target speed up to something like 50kph. It's worth having a drive with HDC engaged just using the throttle to control speed/braking. It's not something you'd want to do all the time as the abs racket gets a bit tiresome but it gives you a pretty good idea of how hdc works. You should find that at above 2000rpm with 0% throttle the torque convertor will lock to assist braking.

Originally Posted by OffTrack

HDC should slow you down in a fairly obvious way. Depending on which gear you are in target speed is 5-9kph with no throttle. Braking becomes more aggressive the closer you get to the target speed, but will cease once you get below it.

You can use throttle to modulate the target speed up to something like 50kph. It's worth having a drive with HDC engaged just using the throttle to control speed/braking. It's not something you'd want to do all the time as the abs racket gets a bit tiresome but it gives you a pretty good idea of how hdc works. You should find that at above 2000rpm with 0% throttle the torque convertor will lock to assist braking.

I took it for another drive last night and it does seem to be working. Before I bled the brakes I did a bit of research on this. My bleed did not seem to be like anyone else's. I used a bit less than one litre of fluid. I bled the brakes normally and then used nanocom to run the ABS pump. When I then re-bled the wheels I got no more air.

I have a good pedal and the brakes work fine. If there was air still in the ABS would it not eventually find its way out and then produce a spongy pedal?

I've posted up a nanocomised version of the wabco abs bleed process in a recent thread.

See here:

http://www.aulro.com/afvb/showthread...28#post1881028

You might be ok as is but one litre doesnt seem right for a full bleed.

Originally Posted by OffTrack

I've posted up a nanocomised version of the wabco abs bleed process in a recent thread.

See here:

http://www.aulro.com/afvb/showthread...28#post1881028

You might be ok as is but one litre doesnt seem right for a full bleed.

This is the the info I used. Below is a copy and paste.
Manual Bleed Procedure with Electronic Control Equipment

NOTE: The electronic control equipment 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). The Meritor WABCO Diagnostic Controller 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 electronic control equipment. Use Pressure Bleed Method if equipment is available; if not, use the Manual Bleed Method.

3. Install electronic control equipment to ECU, or to the modulator assembly and pump.

4. Turn ignition switch ON or power electronic control equipment.

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

6. Activate the pulse function on the electronic control equipment starting with the longest brake circuit, typically the rear.

7. Release brake pedal for 5 seconds and activate the pump of the modulator 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)” on page 14.


10. Repeat Steps 5 through 9 for the remaining 2 [sic] brake actuators.

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.).



At the top of these instruction it says, The inlet solenoid valve should be open (de-energized).
So this is what I did. On Nanocom I pressed the brake pedal. I then selected "Inlet Valve OFF"(for the wheel I was doing). Nothing changed. I then selected "Outlet Valve On"The pedal then sank to the floor(Not sure if it went all the way but it did sink)




I then went to the next page on Nanocom and selected "ABS Pump Relay"
The pump started and the pedal kicked back at my foot pretty hard. I ran pump for about 5 pulsations and repeated the process 3 times.



Do you think I have done this correctly?

When I finished the above I then went and bled the wheels but I got no more air. As I said earlier, my pedal is good and brakes work as well as they did before.

Did you use the power bleed function in the Nanocom SLABS utility?

Or something different?

http://web.nanocom.it/download/WABCO%20SLABS.pdf