ABS parking sensors and handbrake
 

I have a few issues, with the car, not me honest.:D
I have a 2004 cdti deisel.
Front drivers wheel bearing was replaced April, and then the ABS light came on. The speedo stopped working etc. A new abs sensor was fitted and the light went off, and the speedo is working. There is still an issue however.
Under light braking you feel the brakes grind, and the pedal pulses like the abs is kicking in. What could cause this? Not sure if the garage used a oem sensor or not.
My parking sensors are also on the blink. I don't think its the switch as this was replaced a few years back and the reverse lights work. When you select reverse they all sound constantly. If you go out of reverse and then back in there is no sound and they don't work.
Lastly the handbrake is poor. All cables/ rear back plates changed a couple of years back. What can be done to sort this out please?
Thanks in advance

If the brake pedal is vibrating that would normally be a front or rear disc issue
Parking sensors problem mean that one or two are not working. If you turn the ignition on and put the car into reverse, go round the back or the car and put your ear to each sensor. you should hear a clicking noise from each, if one is faulty then you wont hear it and that one needs replacing
Hand brake could be either the shoes not adjusted correctly or the hand brake compensator needing replacement/adjustment

Check out the how to page (https://www.the75andztclub.co.uk/ind...?thepage=howto) for a step by step guide on tightening the handbrake.


The ABS problem has been described on this forum before. See https://the75andztclub.co.uk/forum/s...=282109&page=2. From what I have read on here, the main problem is the magnetic ring becoming dirty, giving an inconsistent reading. You can check which wheel is the offending wheel using this test: https://www.the75andztclub.co.uk/for...d.php?t=139231. Mark with chalk on the tire every time the voltage switches between 0.7V and 1.7V. You should end up with 46-48 chalk lines, which should be evenly spaced out. The pattern of chalk lines also gives some indication about what is broken, but I only remember reading something about that on here and I don't remember what pattern indicates what

the crunching noise does not sound healthy.Was the bearing put in properly ,without damage to the bearing and reluctor .. just a thought .

I had exactly the same problem as you with the ABS. Speedo stopped working, TOAF confirmed front o/s sensor faulty.


Had it replaced; speedo started working again... but I retained the other symptoms, including the weird crunchy bit, and the ABS light came on.


My Rover man found that the rear n/s was also at fault (rust on the sensor, I think) and sorted it all out.


Weird that two related but separate problems seemed to coincide, but there you go - that's a couple of years ago now, and all fine since.


Can't remember what you said in your thread about the handbrake, but have you replaced the compensator?

The rear handbrake could be a stretching compensator, has this been placed with a modified one? No point fitting a new unmodified one.
The rear drums which are part of the rear discs could be pitted and so there is "little" for the shoes to press against, the shoes could be dirty. Shoes not properly adjusted?

macafee2

Thanks for all the help. I think the bearing was fitted correctly yes. Mechanic has not had a chance to look at it yet, i will pass the info to him

Another potential area to consider investigating would be the new sensor may have an issue with not collecting the full cycle of magnetic elements from the new bearing because the gap of the new sensor may be too large, and not collecting the pulses correctly, this could be considered as "The Air Gap"
This happened to me on a few occasions following replacement sensors in the front end, a simple process after extracting the sensors, file down the metal shoulder by a small fraction and ensure the hub where it enters is clean and corrosion free so the sensor sits correctly where it should be. Following this but observing only a fraction to be filed away has fixed the issues. Aftermarket ones work as good as genuine ones as long as the air gap is right.

The ABS sensors are often corroded solid if still the originals. If the garage have resorted to drilling the original out, they could have damaged the sensor ring on the now new wheel bearing. Even the slightest nick could cause the senor to think the wheel is locking up momentarily.