Early 914 brake light switch Options

[isdyl]

Hi, I'm have a difficult time obtaining a brake two pole brake light switch for my 914 here in the uk. It is a Bosch 0343102008 as seen in the photo with the mechanical plunger. It screws into the side of the master cylinder. Bosch have no stock and I have just found one available at a Porsche dealer for £80 which I am reluctant to spend. Mine is leaking and I have tried epoxy to repair it but no luck. I was thinking that there must be pressure in the plunger area when in operation as it leaks and forced past the epoxy, so could I use another two pole pressure switch provided it has the correct thread? (12x1mm I think). Has anyone else replaced their plunger type switch with an alternative? The later cars use a single pole 0343102010 which works in a similar way but I think grounds through the switch body when the plunger is pressed rather than connecting the two poles.

[isdyl]

Hi, sorry to resurrect my old thread, but I'm still having a few issues with brake pressure. I've done quite a lot of searching around but before I waste any more time removing wheels again I thought I'd describe my symptoms and see if I'm barking up the wrong tree!

I replaced the brake pressure switch kindly sent to me by 914Sixer and have bled the brakes a couple of times.When I'm driving or stationary with the engine on I get a clicking/ticking from the flasher relay (but no warning light flashing). If I press the brake pedal the clicking/ticking stops for about 5 seconds and then starts again. It I apply the parking brake when stationary the light on the dash flashes in time with the ticking (as it should). Indicators all work as they should. In some places I have read that the switch needs resetting, but I don't think this is that type as there is no reset button. I wonder if I just need to keep bleeding the brakes - maybe I have air trapped somewhere? I have read that air can get trapped in the brake proportioning valve - could this cause this problem please?

Thanks, Dylan

[Spoke]

I replaced the brake pressure switch kindly sent to me by 914Sixer and have bled the brakes a couple of times.When I'm driving or stationary with the engine on I get a clicking/ticking from the flasher relay (but no warning light flashing). If I press the brake pedal the clicking/ticking stops for about 5 seconds and then starts again. It I apply the parking brake when stationary the light on the dash flashes in time with the ticking (as it should). Indicators all work as they should. In some places I have read that the switch needs resetting, but I don't think this is that type as there is no reset button. I wonder if I just need to keep bleeding the brakes - maybe I have air trapped somewhere? I have read that air can get trapped in the brake proportioning valve - could this cause this problem please?

Thanks, Dylan

This phantom clicking of the flasher relay is unfortunately not that rare. I'm working with a 911 owner with the same problem. The issue seems that if there is some electrical leakage path from pin 49a to ground the flasher will flash (click) without any lights lighting up. If the leakage path is through the brake warning light, it might be so that there is enough current to trigger the flasher but not actually light up the bulb.

You can check this by either popping out the dash gauge and removing the brake warning bulb. If the clicking stops then it has to do with the wiring of the brake warning light.

[isdyl]

Hi - sorry its taken me a long time to follow this up! I removed the wires to the warning lamp and yes the ticking has stopped - hooray! I'll have to start hunting around for the short/leakage now. Thanks - I'll start near the parking brake area as that switch is a bit dodgy. D

I replaced the brake pressure switch kindly sent to me by 914Sixer and have bled the brakes a couple of times.When I'm driving or stationary with the engine on I get a clicking/ticking from the flasher relay (but no warning light flashing). If I press the brake pedal the clicking/ticking stops for about 5 seconds and then starts again. It I apply the parking brake when stationary the light on the dash flashes in time with the ticking (as it should). Indicators all work as they should. In some places I have read that the switch needs resetting, but I don't think this is that type as there is no reset button. I wonder if I just need to keep bleeding the brakes - maybe I have air trapped somewhere? I have read that air can get trapped in the brake proportioning valve - could this cause this problem please?

Thanks, Dylan

This phantom clicking of the flasher relay is unfortunately not that rare. I'm working with a 911 owner with the same problem. The issue seems that if there is some electrical leakage path from pin 49a to ground the flasher will flash (click) without any lights lighting up. If the leakage path is through the brake warning light, it might be so that there is enough current to trigger the flasher but not actually light up the bulb.

You can check this by either popping out the dash gauge and removing the brake warning bulb. If the clicking stops then it has to do with the wiring of the brake warning light.