brake light switch

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Rob_Jennings
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brake light switch

Post by Rob_Jennings »

I've noticed when backing the car in the garage that the brake lights do not always come on with a light touch of the brakes. A heavy press and they come on fine, but it got me wondering if they are on when I brake lightly at other times or even if just sat on a light brake when stationary.

so... how much brake pressure should be needed to light the lights? and does this behaviour suggest the pressure switch is on the way out?
Rob
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minor_hickup
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Post by minor_hickup »

I'm on my third, they've either worked or not so I don't know if its on its way out or not. However mine come on whenever i push enough to operate the brakes. Maybe there is some air trapped under the switch?
Kevin
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Post by Kevin »

Rob does your car have discs as light pressure and moggie brakes are not the norm, it sounds as though the switch is fine maybe the brakes just need bleeding to squeeze a bit of air out as we know the fluid should be changed every couple of years, and we all remember to do that dont we...........................
Cheers

Kevin
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Rob_Jennings
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Post by Rob_Jennings »

disc brakes and servo.

no problem stopping, as tested yesterday when some 'person' in a merc pulled out in front of me on a 70mph road. (sometimes i think people see an old car and assume it must be going slow)

No idea when the fluid might have been replaced last, so I did intend to renew the brake pads and flush the system, perhaps for the few quid it costs it may be worth replacing the pressure switch if that is not normal behaviour.
Rob
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Post by tickman »

Rob_Jennings wrote:
no problem stopping, as tested yesterday when some 'person' in a merc pulled out in front of me on a 70mph road. (sometimes i think people see an old car and assume it must be going slow)
so it is not just me they pull out in front of, also when i am driving my big van! so it is old car and big van so it must be slow! :roll:
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Post by ColinP »

I had the same symptoms,

eventually the brake lights just didn't work unless I stood on the pedal...

Fit a new switch (and keep one as spare!)

If the old one comes out easily, then it isn't necessary to bleed the brakes - the switch can be replaced without needing to re-bleed. (use a dropper to fill up the switch and cavity).

Cheers,

Colin
Rob_Jennings
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Post by Rob_Jennings »

If I replace the switch can I not just press te pedal to fill up the cavity before fitting the new one, or is that just going to end up with fluid everywhere.
Rob
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Packedup
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Post by Packedup »

Personally, if I was going to go the bodgetastic route of fitting without bleeding, I'd have someone very slowly pressing the pedal from start to finish of the job, to make sure fluid is going out and air cannot be going in.
Willie
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switch

Post by Willie »

Should be no problem, swop switches as soon as possible with your finger
over the hole, when swopped , loosen new switch enough to allow fluid to start seeping out. Lock it up tight and the brakes should be as per original.
Willie
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Post by paulk »

I had a similair problem when I fitted the new M/c on Maude that altough I had brakes I had no lights.

Eventually I think I took the switch off and using a small drill gave it a prod to make sure it wasn't sticking then put it all back together with some fluid in the little switch cavity. with a quick turnover and spin on I managed to put it back together without the previous airlock which I assume caused the problem. I didn't trust the non-bleeding approach and gave front a quick bleed through without any problems.
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minor_hickup
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Post by minor_hickup »

Or if you put cling film in the master cylinder cap to stop air entering when you do it. When you remove the switch fluid will then move up the cavity instead of down it, fill the switch up with fluid and screw it in, then wash away any spilt fluid and remove cling film....voila!
Kevin
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Post by Kevin »

then wash away any spilt fluid
But please remember that brake fluid is a good paint stripper so be careful.
Cheers

Kevin
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