94 VR Brake Issue

[Twisted]

G'day there.

I seem to have a problem with my 1994 VR commodore. Just recently (Last week or so), the brakes on my car do not work until the temperature guage reaches the first line on the the dash.

When I say "Do not work", I mean, I press down about half way and there is a sickening shudder accompanied by a shaking brake pedal. Once the temp gets to the first line, the "ABS Off" light turns on and my brakes work again.

I've already tested and it's the driver side front wheel's sensor that is faulty. This problem has only been happening for the past week and the brakes worked perfectly fine up until now.

Could I get some assistance please?

[Darcon666]

1st thought is air in the line, so bleed them..
2nd, as you said changed the faulty ABS sensor and see if this fixes it, otherwise it could be the ABS module...
3rd, sticky piston in the callipars - rebuild time.....

4th, unfortunately things don't last forever especially mechanical stuff... they break/wear out/fail.

Good luck

[Brett_jjj]

Sometimes air can get trapped in the ABS modulator and can cause problems.Some scantools have a brake bleed option whick activates the ABS while you bleed the brakes,this lets any trapped air through the ABS modulator.If you dont have access to a scantool,You can try locking up the brakes on grass or gravel so the ABS activates,this should let any trapped air through the system which can then be bled out,so it might be worth a try.

[hako]

As you've diagnosed the problem to lie in the drivers side front sensor you will need to check firstly that the cable is connected properly to the hub, bolt is tight and cable does not appear damaged. Maybe also, if it looks OK, remove the bolt and pull the plug off and reinsert as maybe water has gotten inside the connector. If connector and plug seem OK, then the fault may lie in the sensor itself which is located inside the hub....and the only fix in that case is hub replacement. You could temporarily pull the ABS fuse - you will have no ABS but the car should brake exactly the same as a car without ABS. Another thing to check is the main connector to the ABS unit under the bonnet - water can enter the connector and corrode the pins/connectors and cause all sorts of problems.
Good Luck.

[RX25SE]

From what you describe it sounds as if the system goes into ABS mode when the brakes are applied (hence the shudder) and when the ABS warning lamp comes on the system works as a non ABS system.
As above check the wiring connector to the ABS unit and, if you can get hold of a scan tool, check for codes in the ABS system.
You can get a rough idea if a wheel sensor is working by connecting it to a digital multimeter set on A/C volts and spinning the wheel. This should generate a small voltage.

[justbad4you]

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