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accumulator replacement question


wht89reatta

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A quick update. I just replaced the accumulator in about 10 minutes, and I think i must be the luckiest sob on the face of the planet, for a little over $100 i got a working CRT touchscreen, a working healdight motor, a taillight, and a working brake accumulator. :{D I'm so excited right now. I just figured id share my jubulation. Thanks again for all the help guys!

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You mentioned you got one from a junk yard. I buy quite a few ABS pumps, pressure switches and accumulators from salvage yards. Rarely do I get a good accumulator. 90% of the time I throw them away.

The reason the accumulators go bad is the nitrogen leaks out and then more fluid is held in the accumulator meaning less nitrogen to compress. You cannot compress fluid. The pressure will drop fast in a shot accumulator causing the pump/motor to run more often and this will wear out the motor faster.

Before unscrewing the accumulator be sure and pump the brake pedal, with the key off, about 25 to 40 times and still I wrap a rag around the base of the accumulator when unscrewing it. If is seems to unscrew hard, then you still have pressure in the system. If it unscrews easy after initially breaking it loose, then all of the pressure is out of the accumulator.

The following is a test for an accumulator.

Procedure for testing an accumulator.

Turn on the key and have the radio and anything else off that makes noise. Wait for the red and yellow lights to go out and a few seconds later you will hear the pump stop running.

Rapidly pump the brake pedal about 4 times and see it the red light comes on. If it does, wait for the pump to build up pressure again and the light will go out. Wait again for the pump to stop running and then pump the brake pedal 3 times to see if the red light comes on.

The purpose here is to see how many pumps it takes to get the red light to come on. The higher the number the better the accumulator. A new one will be about 7 pumps and a shot one would be one pump.

Two pumps should be replaced and three is marginal.

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Thanks for the info jim, i'll have to investigate further to see just what condition it's in but the old one i had on my car was completely shot (motor was running all the time), so for the time being, even a half good accumulator is better than a completely broken one.

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Thanks for the info jim, i'll have to investigate further to see just what condition it's in but the old one i had on my car was completely shot (motor was running all the time), so for the time being, even a half good accumulator is better than a completely broken one.
Even with a completely bad accumulator the pump should shut off after running 10-15 seconds if the brake pedal is not pressed. If your pump actually is running all the time, you have more problems than just a bad accumulator... like a bad pressure switch or faulty pump.
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Luckily enough i took the whole pump assembly so i shall try the pressure switch first, but on a lighter note i know the accumulator was bad because i was getting a low abs pressure warning on my crt and after i replaced it the warning went away and is braking as it should. So with your suggestion i can deduce that the pressure switch might have also gone bad.

I will update further when i have a little time

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good/bad news, i just went out and checked the condition of the accumulator i just installed. After about 30 seconds of the pump being on it went off and cycled about every 30 seconds or so without me touching the brake. When i did touch the brake i got about 1.5 brakes before the pump came on. :/ Well at least this on bought me a little time to find another replacement

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A quick update. I just replaced the accumulator in about 10 minutes, and I think i must be the luckiest sob on the face of the planet, for a little over $100 i got a working CRT touchscreen, a working healdight motor, a taillight, and a working brake accumulator. :{D I'm so excited right now. I just figured id share my jubulation. Thanks again for all the help guys!

So you got a marginal accumulator that will need replacing... as a fellow "junker" you still did very well. The bargains are out there, glad you went there and looked!

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