85 240 DL

I have had spongy brake pedal for about a month now. The fluid drops sometimes alot. I have replaced the master cylinder about 3 years ago and the pads and rotors about 3 months ago.
I have inspected for leaks and the ONLY place that was wet was the ???switch??? on the portioning assembly under the car?

Is this a commom leak point for brake failure?

Thanks
Steven
85 240 DL
http://www.cardomain.com/memberpage/494646
95 850 T5-R
http://www.cardomain.com/memberpage/520831

I got VERY lucky. The switch was loose. Tightened and the brakes are strong and solid again...sweet

I assume you are talking about the junction fitting and warning light sending unit switch that is mounted behind the driver's side front wheel. Most of the time a leak will develop from the plastic switch. If you are very lucky, tightening down the switch will stop the leak. But 9 times out of 10, not even replacing the switch will work. You have to replace the whole junction box, which will come with a new switch.

Inside that switch block is a piston that fits through two 0-rings. The 0-rings seal off the brake system pressure. Once an 0-ring is leaking, the leak will continue and the seal where the wire enters the switch is not designed to hold that level of pressure.

I have heard that the junction block/switch can be refurbished. Disassembly, replace 0-rings and reassemble. However, the remove/replace/bleed block replacement job has such high labor content that going with new makes better sense.

Good Luck,

Bob

:>)

It sounds like the valve is the problem however the 240 master cylinder is prone to failure. I've replaced mine twice and possibly three times since I've had the car.
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Simon 80 240 296k 17 years.

Fortunately it happens slowly. When it starts I get a cheap one from E-bay and wait until I can't stand it any longer or no amount of pumping will keep my from rolling while stopped on a hill. Fortunately it's an easy job/
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Simon 80 240 296k 17 years.

The best thing to do other than have a quality line wrench for the fittings is to soak the fittings with PB Blaster or Kroil. Use a wire brush to remove much of the road grime, rust and cat hair that has built up. Then apply the penetrant repeatedly for DAYS before attempting to removing any of the lines. This will pay dividends. Do not completely remove any single line unless you have all of them loose first as one line completely off means lost fluid. Good luck.

Randy

with higher mileage, that is the most likley culprit, escpecially since you have ruled out the MC. They are kinda a pain to do becaus of the tight space, make sure you mark each line well and take pictures with a digi camera if you can. get some flare nut wrenches to avoide stripping the nuts or you will have a headache real fast, every since i got my flare nut wrench set, i find brake work much easier!

Make sure you do a very good bleed aftewards too! I recommend a power bleeder if you have acces to one.

good luck
chuck
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'88 244 174K, '87 BMW 325e 177K (used to feed a '84 245, '84 244, '85 744)