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MG MGA - Brake light switch - Faulty or Hydraulics?

Hi folks, I have a quick question for the experts.

This weekend I flushed and bleed the brakes and clutch in my 1600 using a Motive pressure bleeder (Dot 4 fluid).

Upon finishing I took the car for a short drive. All worked well. The brakes pulled up nicely and the pedal was firm. However when I arrived back in the garage I noticed my brake lights were on (note wheels are not locked up). Upon closer inspection I found that when I press lightly on the pedal the brake lights work as per normal. However when I press firmly, the lights stay on. In 90% of the time, turning the ignition key off and straight back sees the brake lights go out.

Do I have residual pressure my brake lines or a faulty switch?



Hi Steven, it sounds like you have a bit of residual pressure going on. Suggest you try slackening the brake push rod from the master cylinder a little and see if you get normal operation of the brake lights. Your lovely new brake fluid may have changed things a little bit. If you have no change then it could be the switch sticking.

Best regards
AR Terry

Thanks Alan, I've done some more investigation and have discovered that the right rear wheel is indeed binding. Turning back the adjuster frees the drum but but it becomes stuck (again) after applying the brake. The left rear wheel is fine so I am assuming that the problem lies in the right rear wheel cylinder or there is some crud in the line between the wheel cylinder and the flexible brake line.



Perhaps the innards of one of the flexibles has collapsed.
Graeme Williams

Yes that could be possible then the hose could work like a one way valve.
AR Terry

This thread was discussed between 28/02/2016 and 03/03/2016

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