'93' 940 Brake failure warning light.

[Robert]

Greetings All
Yesterday my 940 (130k miles) displayed the brake failure light on the
instrument panel when applying the brakes. Checking the veh' book it stated
the fluid may be low. The fluid level is ok showing no loss of fluid. Today
when starting the veh' the brake failure light is on all the time. I have
again checked the fluid level, it's ok with no loss of fluid. The brakes
work ok, the pedal 'feel' and movement are normal, I have not gone over any
holes or bumps or clipped the kerb.
There are no strange smells or noises when driving or applying the brakes,
there are no 'tell tale' signs of fluid on the floor or around the brake
disc/pads. I do not undertake any harsh/sudden braking or handbrake turns.
My veh' as been regulary serviced and maintained to Volvo standards.
Any advice or guidence as to why the warning light should suddenly come on
and stay on will be much appriciated.
Many thaks Rob.

 

[Roland Messerschmidt]

Hi Rob,

Any advice or guidence as to why the warning light should suddenly
come on and stay on will be much appriciated.

break pads worn out?


Roland

 

[Mr. V]

Possible imbalance in the system: see

http://brickboard.com/FAQ/700-900/Brakes.htm#BrakeLightOnAfterBleeding

Or, a failing master cylinder.

 

[Mike F]

Greetings All
Yesterday my 940 (130k miles) displayed the brake failure light on the
instrument panel when applying the brakes. Checking the veh' book it stated
the fluid may be low. The fluid level is ok showing no loss of fluid. Today
when starting the veh' the brake failure light is on all the time. I have
again checked the fluid level, it's ok with no loss of fluid. The brakes
work ok, the pedal 'feel' and movement are normal, I have not gone over any
holes or bumps or clipped the kerb.
There are no strange smells or noises when driving or applying the brakes,
there are no 'tell tale' signs of fluid on the floor or around the brake
disc/pads. I do not undertake any harsh/sudden braking or handbrake turns.
My veh' as been regulary serviced and maintained to Volvo standards.
Any advice or guidence as to why the warning light should suddenly come on
and stay on will be much appriciated.
Many thaks Rob.

This indicates a pressure difference in the 2 brake hydraulic circuits.
If both reservoir halves are full, then look for a leak in the circuits
somewhere. If there is no leak, then the master cylinder is bad (fluid
leaking past the piston back into the reservoir) or the warning switch
is faulty, or its wiring is shorted to ground.

--
Mike F.
Thornhill (near Toronto), Ont.

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