Chippy
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| posted on 19/4/06 at 09:59 PM |
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Anti lock brakes.
Hi All, does anybody know of a web site, or book that deals with anti lock brakes, ideally Ate, as fitted by Ford. I have got a continuous ABS warning
light, and the front wheels skid under braking, while the back don't seem to have much effect, (hand brake works fine). I have blead the system
twice. Done a Google for Ate, and a search on here, with no joy. Any assistance greatly appreciated. Regards Chippy.
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NigeEss
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| posted on 19/4/06 at 10:44 PM |
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Hand brake is normally independent o fthe ABS system.
It's worth checking the wheel sensors are ok, clean and haven't come away from the sensor wheel.
Also check all connections and wiring plugs in the system. Most problems I've come across over
the years have been down to the above.
Nige
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Liam
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| posted on 19/4/06 at 10:44 PM |
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Constant light menas there's a problem so it's disabled, hence the locking up. Problem is normally sensors with ABS - try giving them and
their toothed wheels a good clean. Other than that you're into system specific troubleshooting. They often know what's wrong with
themselves, if only you can find out how to get em to tell you. If cleaning gives no joy, measure the resistance of the sensors (disconnected). They
should be the same (in the Kohms in my experience). Short or open circuit and that sensor is probably duff.
Hope that helps,
Liam
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darrens
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| posted on 19/4/06 at 11:08 PM |
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I have just had this exact same fault but on a Renault. This is also had a continuous ABS light, and brake/handbrake warning light. Problem was wiring
to the ABS module, one supply cable had perished (exposure to the elements). Re-done cable and it reset automatically.
Would have thought if it's a sensor fault this would only bring the light on after moving the car, unless the sensor has a complete short across
it.
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muzchap
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| posted on 19/4/06 at 11:29 PM |
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Ok - you need to run a process of elimination.
Nip down to the scrapyard or beg/steal/borrow another sensor (that works!!!) - attach this 1 at time to each of your 4 sensor locations - if the light
goes out any location - you have identified the problem area - if the light remains on - you are looking at further diagnosis.
What year is your car? You might be able to short across the ECU connector and get the fault code number back out - pinpointing the exact ABS
issue.
I'd agree with the other posts though - try cleaning first.
------------------------------------
If you believe you're not crazy, whilst everybody is telling you, you are - then they are definitely wrong!
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britishtrident
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| posted on 20/4/06 at 07:21 AM |
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As already said check the wiring, sensors and reluctor ring. If the handbrake is dragging it can also cause the ABS light to illuminate when you
press the foot brake first time after stating off.
Also reboot the system -- pull the fuse or disconnect battery.
If you can borrow an osscilloscope to check the sensor outputs it can save a lot of time.
I have actually got a diagnostic code reader for some older Ford ABS system
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mackei23b
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| posted on 20/4/06 at 08:05 AM |
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I had this on a honda, yes it was a fault in the braking system: the fault was a rear brake light out, replaced the bulb and all was OK!!!!!!!
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NS Dev
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| posted on 20/4/06 at 09:08 AM |
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locking fronts and no rears means no pressure available in the system, so it sounds like your pump is not operating.
The rears are purely operated by the pumped system, whereas the fronts are pressure assisted but will still work with no pump action.
Sensor failure will not stop the pump working.
When you bled the rear brakes, did the pump operate? They should "self bleed", you need the ignition on, you should hear the pump running,
then hold the brake pedal down and open the rear bleed nipples, they should squirt fluid without pumping the pedal, the pump does that for you.
If the pump isn't working, the rear brakes wont bleed. You can't bleed the rears without the ignition on with the Ford system.
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
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Chippy
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| posted on 20/4/06 at 09:42 PM |
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Hi Guy's, thanks for all the comments. I will try to answer with what I have done so far.
1/ The car is ,of course, a Locost. The system is from a Sierra, 1989, 2 wheel drive, (not my 4x4 donor).
2/ All of the sensors, and toothed wheels were cleaned and greased when I overhauled the hubs, I have checked and all are tight.
3/ The Ohms reading of each sensor is as follows- N/S F 1.083- O/S F 1.072- N/S R 1.102- O/S R 1.073 as all are pretty close, within 0.030, I guess
this is acceptable. I have also tried a spare sensor in each position, one at a time, made no diference.
4/ When I bled the rears it was done as per Haynes manual, ignition on press brake pedal fully for first wheel, and half way for second.
5/ The pump runs when first turning on the ignition for about 10 to 15 sec's. It does the same if the brake pedal is pressed whilst
stationary.
As you can see tried most things, but with no luck so far.
britishtrident, where are you situated?
Regards Chippy.
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britishtrident
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| posted on 21/4/06 at 04:02 PM |
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About as far away in the uk as to make it a postal job central scotland -- need to check which models the unit covers anyway.
With a lot of ABS systems if a fault has logged you have to drive the vechicle at a speed over 15 mph to let the system do a full diagnostic before
it wll put the light out. Even them the fault stays logged until the vehicle has completed X drive cycles with out the fault re-occurring.
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britishtrident
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| posted on 22/4/06 at 08:22 AM |
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Check the model coverage of my diagnostic --- unfortuneately only it covers ATE (Teeves) MK IV and MK II but only 1992 onwards Ford
Escort,Transit and Granada-Scorpio.
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omega 24 v6
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| posted on 22/4/06 at 08:42 AM |
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You could try unplugging each speed sensor in turn and metering (ac volts) the sensor voltages with the wheel spinning. They should be roughly the
same all round at the same wheel speeds. As said before though this would only put the light on after getting the vehicle moving
Other than that try borrowing an ECU or a Modulator/pump unit.
As ever Good Luck.
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Chippy
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| posted on 22/4/06 at 10:50 PM |
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Hi all, thanks for the many useful tips. I have in fact now located the problem, it was a broken wire to the low fluid switch, feel such a bloody
fool, but it was impossable to find without going through each and every blasted wire to the ALB control unit. ATB Ray.
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