ABS gremlin on 3B

[dan_b]

And here's the next problem that my beautiful S2 has thrown up on me...

When braking at very low speeds, I'm now getting what feels like the ABS cutting in fairly frequently. This is silly.

I've got Porsche 4-pots with Ferodo DS2500s up front, and EBC Greens on the back. Recently replaced a sticking rear left caliper. Front right caliper is squealing pretty badly under light brake pressure, still waiting for new anti-squeal shims from VAG Parts (Martyn?!)...

Anyway, the ABS coming in is I'm sure not related to having different brake compounds. Could it be a faulty ABS sensor on one of the wheels? If so, how would I diagnose which one it is? How easy is it to replace?

I can of course switch the ABS off, and when I do that, braking is normal, but I'd rather not drive the whole time with ABS off, just in case the unexpected happens.

Help! Is this going to be expensive?

[rotoryboy]

Mine did this on my aby and turned out to be the sensor slightly off. Repositioned it, perfect.

[dan_b]

Where are these sensors? Could it have just come loose then?

[S2central.net]

Almost certainly a duff ABS sensor as you suggest - or wiring faulty to it.

The good-news is its very easy to find this fault on the ABS variant which does NOT have the cancel switch as VAG-COM gives access to the info. However, bad news is that the earlier variant on 3B needs a special Bosch/VAG tester for such tests.

You could try taking resistance measurements across each ABS sensor and see if one is different. The sensor is connectorised near where it enters the bodywork.

New sensors aren't horribly expensive, but they are a bitch to renew as years of rust invariably means the old ones need drilled out from their location in the hub carrier.


Paul

[dan_b]

How did I know that the 3B was going to be worse

I'm really hacked off with my car at the moment.

[spink]

As yet i have never had one sensor seize in solid, and ive removed around 30 in the last year.Most come out using fingers only, if you find you need a spare one i have several.

[dan_b]

Hi Spink
I think I'll be needing some then - there's definitely something hooky going on, but I need to find out which one first and I don't even have a multi-meter!

Dan
Not particularly tooled up

[sla_s2]

i had the same problem on my 3b for three years (shame on me) until some guys used the hammer and "repositioned" the abs sensors it is perfect now!!!

sla s2

Hi Spink
I think I'll be needing some then - there's definitely something hooky going on, but I need to find out which one first and I don't even have a multi-meter!

Dan
Not particularly tooled up

[dan_b]

Just replaced my anti-squeal shims in my front Brembos: have to say they were in a pretty bad state! Hopefully that'll cure the squeaking, and might have an impact on the ABS sensor. Well, I can hope anyway... If not, I'll be back asking more quesitons!

[newsh]

pop out the sensors, clean and re-position them, you can fit new plastic caps to do this, while you're there blow out the teeth on the hub that the sensor "counts" they can become filled with rusty debris..

[dan_b]

Where are they actually located? Anyone got a photo/diagram?