ABS warning light and noise from axle/ gearbox

[Orbis]

Hello everyone,

It's been a while. Yesterday I was driving with my MK1 on the highway and suddenly the orange ABS warning light came on. It stayed on untill my next stop. When I started the car again, it was still on, but it went off after one minute. When I came home later, the light was on again and when I was slowing down for parking my car, I heard a terrible grinding noise for 2-3 seconds from underneath the car (left side) and then it was gone again. (like a grinding splined shaft or so???) After that I was still able to drive the car onto my parking.

A scan with VAG-COM told me this:

00283 - ABS wheel speed sensor; Front Left (G47)
35-00 - -

I've taken the front left wheel off and I've seen nothing abnormal. sensor was still well connected and the drive shaft looked at first sight normal. I don't know internally.

Is this something common? Any ideas? What should I check first now?

I will have a further look at the weekend. I hope it's not the gearbox.

All help is much appreciated!

greetings

[insanitybeard]

Possibly a split ABS reluctor ring on the outer CV joint casing grinding against the ABS sensor? It'll be difficult to see with it all installed as the reluctor ring will be recessed quite a way into the hub carrier.

The below picture is from a Mk2 Galaxy but shows where the reluctor ring is with the wheel knuckle/ hub carrier removed:


[attachimg=1]

[Orbis]

Ok, many thanks for the tip and the picture! Sunday I will have a good look at it. I keep you informed

[Orbis]

ok, the reluctor ring is fine, but the sensor has a higher resistance than the other side. I assume I have to replace the sensor.
I still can't find an explenation for the sound. Was the car thinking it had to use the ABS because of a faulty sensor? I didn't feel the brake pedal shudder. I also don't think it was a normal ABS sound.

Today I drove it again around the block and it didn't come back. Except for the ABS warning light. I'm going to replace the front sensors anyway. Not easy because they're well corroded in :p

[insanitybeard]

If you heard a definite physical grinding noise then keep an eye on it- is the CV boot all secure and not leaking? Are the brake discs and pads in good order? And is there any play detectable in the wheel bearing?

[Orbis]

Today I made the first longer drive after the repair. So I replaced both front ABS sensors and I reset the fault code. And everythinng was fine. No dash lights or noises

So the noise had to come from the ABS pump but to me it seemed to be something else, also because there was no brake pedal shudder. I will test the ABS system this winter in the snow to hear what noise it makes then :p

The boots from the drive shafts look stil in good condition. My brake discs are approaching the minimum thickness so I will replace them by the next brake pad change (but my pads are still very thick). I feel no play in the wheel bearings. Is it normal tot not feel any play after 215000 km or 133k miles? I think I'm at a point where a lot can go wrong.

things that are never replaced or refurbished before: drive shafts, brake discs, whole clutch (manual transmission), alternator, power steering pump, coolant pump, A/C compressor (or clutch or bearing).

I've also removed the drive belt to feel and spin everey bearing and I actually didn't notice noises or play.

Only the tensioner, tensioner pulley and idler pulley are replaced this year.

[SilverBeast]

Could the shield on the lower ball-joint have been rubbing against the disk? Mine made a horrendous noise when reversing for a while (but OK going forwards) which turned out to be this.

Or maybe a stone had got between the disk and the shield? 

[Orbis]

The shields of the lower ball-joints are ok. But I will remember it for in the future. A stone is possible and maybe it also damaged the sensor. But the ABS light was there before the noise. Maybe I have to stop thinking about it

I really was surprised by the space between the sensor and the ring. you can barely put a piece of paper between it I think. Maybe the distance decreases by a wearing wheel bearing? but there's still no movement or noise detectable. or is that a weird theory :p

anyway, thanks for the help again!