Poor brakes and warning light constantly on

[Leekade]

I wonder if anyone can help diagnose a problem without my having to replace the whole system!

I’ve taken out the car and the brakes have been really poor with the warning light constantly on.

The rear end is jacked up and, with the engine running, when the pedal is pressed briefly the back wheels remain locked. However when the pipe is removed from the vacuum tank the wheels lock when the pedal is pressed and release afterwards. This is obviously not right.

Can anyone point me in the right direction?

Adrian

[politeperson]

Maybe you have defective low brake fluid level indicators in the reservoir and a stuck reaction valve at the end on the master cylinder.

1)With the ignition on, unscrew the brake reservoir cap and float. Invert in whilst looking at the light and see if the light flashes as you push the float switch. If so, you need a new cap/switch.

2)Take a Phillips screwdriver and remove the white circular disc at the and of the master cylinder. You should now be able to see the reaction valve in the center if the master cylinder. Pull it out, clean it. Replace it and put everything back together again. Use red brake grease if you have anything. They can stick on cars that are not used much. And ones that are!

See if that fixes everything?

[Leekade]

Thanks, James. With the weather being so good today, I’ll be trying your tips later and I’ll report back...

Cheers
Adrian

[angelw]

Hello Adrian,
The Brake Warning light also doubles as the Handbrake On warning. I've seen quite a few examples of faulty Handbrake Switches that keeps the Brake Warning light illuminated.

The fluid level switch is closed circuit when the fluid level is low. Accordingly, a quick check to see if the brake fluid reservoirs switches are at fault, is to disconnect the leads from the fluid reservoir caps. This will simulate a safe fluid level and the Warning light should be extinguished. If the Warning light remains illuminated, I would be investigating the Handbrake Switch for fault.

I come from the World of Machine Tool Automation, where its typical for critical circuits, such as Emergency Stop, Lube System failure, etc, to fail safe. That is, if the circuit is compromised by a broken wire, then the same will occur as if these critical functions were activated normally. It's surprising to me that a critical circuit such as a brake fluid level warning wouldn't also be designed to fail safe. A broken wire to the reservoir switches will always display a safe condition, irrespective of the fluid level.

Regards,

Bill

[Leekade]

Hi Bill

Thanks for the advice and information.

We were hoping to look at the brakes yesterday but the ignition system became more pressing as I broke down when visiting the local petrol station - we have hot starting issues which may form another thread. Just investigating the options now...

Cheers

Adrian