Rav4 Braking Problem

[nrg]

My dads got a 98 Rav4. Recently his brakes have been messing up. When he brakes the abs seems to come in even though there is no need for it. The ABS light isn't on. Its a GX model with 70000 miles. He's had it in the local toyota garage a few times now and they've replaced things which still haven't fixed the problem. They linked it onto the diagnostic machine and it showed nothing wrong. Anyone have any ideas? Could it be the sensors?

[jonbr]

A friend of mine just had the same problem on his Smart car. Turned out that some of the teeth on the geared cog, that the sensor monitors, had sheared off. This cause the ABS system to not know what was going on. Took his garage several days to find and rectify the fault.

I haven't described that very well but I'm sure the garage would understand. :)

[sjrainsford]

Yep, I understand what ya mean!

Also, something simple like dirt in front of the sensor can make it miss teeth on the count wheel.