1990 Buick Regal Coupe Brakes Problem [long]

Hello,
I have a problem with brakes in this great GM 1990 ABS brakes systems ;) Sometimes (always after night) when i push brake pedal the brake light (red)
is lighting for about 3-4 seconds. ABS pump is works. The same thing is coming when i push the brake pedal 3 or 4 times (pumping). Where is the problem?? Accumulator or Pressure Sensor?? Or both?? In Poland (I live here so sorry for my English) is very expensive to find the problem. Master Cylinder is early new from USA. Anybody have this problem??
Greetings Kylo Buick Regal Coupe 3.1 V6 www.buick.republika.pl
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Kylo wrote:

How about checking the fluid level in the reservoir? Maybe add about one ounce of the correct brake fluid.
---Bob Gross---
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"Kylo" wrote

I would guess that you probably need a new accumulator. This is the black ball type looking thing screwed into the side of the ABS unit. It was a common problem back in those days.
In order to properly diagnose it, you would need some special tools to be able to monitor the amount of time it takes the ABS motor to bring the system up to specified pressures. But that's normally the one item that went belly up. Anything more.....and you are usually looking at replacing the entire ABS unit which is quite expensive.
Ian
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