Brake fluid light flashing when braking?

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dffrntwn
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Brake fluid light flashing when braking?

Post by dffrntwn »

'84 633csi USA.

Just replaced my brakes with all new calipers, pads, and pad sensors.

Bled the system, and the master reservoir is full.

Now every time I apply the brakes the brake fluid level sensor light flashes in the gauge cluster for a half second and immediately turns off. If I pump the brake pedal it flashes perfectly in time off and on again with each stroke. ](*,)
1984 633csi 5-speed, (1982 Honda CR250, 1982 Toyota Pickup, 1981 Lancia Zagato Spider, 1964 MG MGB Roadster).
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hornhospital
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Re: Brake fluid light flashing when braking?

Post by hornhospital »

Check the float on the sensor. Sounds like it's stuck.
Ken Kanne
'84 633CSi "Sylvia"; '85 635CSi "Katja";'85 325e "Hazel Ann"; '95 M3 "Ashlyn"
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dffrntwn
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Re: Brake fluid light flashing when braking?

Post by dffrntwn »

hornhospital wrote: Thu Feb 22, 2018 3:03 am Check the float on the sensor. Sounds like it's stuck.
If it was stuck would it not stay on all the time, not flash in time when touching the brakes?
1984 633csi 5-speed, (1982 Honda CR250, 1982 Toyota Pickup, 1981 Lancia Zagato Spider, 1964 MG MGB Roadster).
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Brucey
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Re: Brake fluid light flashing when braking?

Post by Brucey »

there are many brake warning lights; are you absolutely sure it is the fluid level one? To check, lift the sensor from the reservoir; the same light should come on.

BTW it is possible that you have a dodgy ground connection somewhere and that is why the light is coming on.

cheers
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dffrntwn
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Re: Brake fluid light flashing when braking?

Post by dffrntwn »

Brucey wrote: Thu Feb 22, 2018 5:39 am there are many brake warning lights; are you absolutely sure it is the fluid level one? To check, lift the sensor from the reservoir; the same light should come on.

BTW it is possible that you have a dodgy ground connection somewhere and that is why the light is coming on.

cheers
Absolutely positive. It flashes every time I hit the brakes and immediately turns off again.
1984 633csi 5-speed, (1982 Honda CR250, 1982 Toyota Pickup, 1981 Lancia Zagato Spider, 1964 MG MGB Roadster).
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TN_M6
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Re: Brake fluid light flashing when braking?

Post by TN_M6 »

But as Brucey said there are also sensors on the hydroboost. Best guess you have one of the pressure sensors going off every time you apply brakes the pressure drops before it can recharge. It might be the sign of a bad brake bomb - the nitrogen charged accumulator on the hydroboost system. Can you apply you brakes at least 10x after you shut the car off before the pedal gets stiff? Maybe while bleeding the bomb fully discharged and failed ?
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sansouci
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Re: Brake fluid light flashing when braking?

Post by sansouci »

+1 for the bad brake bomb.
Sansouci
84 E24 633Csi Auto, Bronzit/PearlBeige 6997510
93 E32 740il M60 Auto, Alpenweis/Ultramarine
60 528i M30 5-speed Green/Beige (crushed)
71 240Z 4-speed White/Blue (rusty & sold)
65 396 Chevelle 4-speed, Marina Blue/Black (stolen)
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