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Brake Test


Retired w/Reatta
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Within the last few weeks I had the accumulator replaced and the system flushed.

I did the standard seven-part brake test today. Looking back over my records the numbers haven't changed much:

1) lights on - 11

2) full pedal pumps - 12; level ok

3) lights off - 15 sec

4) pump stops - 29 sec

5) # pumps - 1,2,2,2,2 (pump runs for about 8 seconds)

6) less than 1/2"

7) yes for audible/pushback thump

According to the averages I'm way off the line for numbers 2, 3, 4 and 5.

Does this mean a faulty accumulator and/or a failing pump?

The brakes work great in real time.

Thanks for any suggestions.

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Question by Padgett about step 5 of Test #2:

Step 5 - what is a normal time to fill (25-40 seconds ?)

Good question. I just checked my car and from key on until the pump stopped running was 44 seconds. However the red brake light went off at 31 seconds. It would be good if others would do the same test and share their results so we could come up with an average time (or range) that could be considered normal. Maybe Barney will give his thoughts on this as well. He actually wrote the test.
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Marck, I can't answer your question for sure. My comments might be off base because I was basing what I said off how my car reacts and what I have read here. The first post I made to this forum, when I got my car in 2007, was about what would cause the red brake light to flicker when I hit the brakes. I was told to take the brake test and after doing so I determined the accumulator was bad. I only got one pump, sometimes 2, before the red brake light would flicker. It wasn't to the point of actually staying on for any period of time. I ordered a new accumulator from gmpartsdirect.com and the problem was fixed.

A few minutes ago I looked a my notes and I had written that after the new accumulator was installed I got 3-4 pumps before the pump started. I just went out and tested my car again and I now get 2-3 pumps before the red light comes on. I have noticed the pedal travel is a little longer now than It was when I first got my car... probably due to wear on the brake pads.

It's possible that the performance of a new accumulator is going to vary from car to car, even with a brand new accumulator installed, due to a number of factors.

  1. The brand, how long ago it was made, and the amount of nitrogen charge it initially had, could make a difference in how a new accumulator performs.
  2. The pressure switch cutoff point could be slightly different from one switch to another thereby varying the amount of reserve pressure stored in the accumulator.
  3. The amount of air trapped in the system could effect how much fluid has to move from the accumulator to compress the air before the system is filled with fluid.
  4. The distance the pistons have to move before engaging the rotors would make a difference, especially if the adjusters in the rear pistons are stuck and not working.

There are a lot of folks here who know the TEVES system better than I do. Maybe they will chime in and set the record straight.

Edited by Ronnie (see edit history)
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Guest Richard D

Red light off-24 seconds, yellow light off 25 seconds, pump stop 30 seconds (after 24 hours of not running) 3-4 pumps before pump starts, Amazon accumulater about 5 months ago.

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Stanley....... you are wise to order a new accumulator. If you install it, do the test again and you may find like Marck, that the pump is still turning on at 2-3 pumps.

Without some instrumented way of testing the components, we are just changing parts.

Example....your accumulator might be good, but the pressure switch might be turning off the pump before the system gets to 2400 psi. this will reduce the number of pumps you see.

Maybe this winter I will build a test station with pressure gage and a more accurate way of measuring the amount of fluid stored in the accumulator. I could then evaluate accumulators and pressure switches.

There is also the possibility that as the pumps get older (and wear) it takes them longer to build pressure. This is another good reason to flush out the old dirty brake fluid, it will wear the pump faster.

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Yesterday I helped (I did all the work) a local install an accumulator. He ordered if from Amazon.

With his old accumulator, the pump would turn on with the second pump of the brake pedal.

With the new one, it turns on with the 3 pump.

I am somewhat dissappointed with these NEW accumulators. I had hoped that we would get 4-5 pumps but since there is little history from really good new accumulators, we may never know what to expect.

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Barney 2-3 pumps is what I get out of my accumulator that was installed in 2007. It came from gmpartsdirect.com.

Do you think the instructions you wrote, Accumulator Test*-*ReattaOwner.com, should be revised to say: "A good accumulator might give you 3-4 pumps before the pump starts." instead of: "A good accumulator might give you 5-8 pumps before the pump starts."?

Also what do you think a would be the normal "amount of time" for test 2-5? I have been asked this question and I would like to make it clear in the test.

"5. Turn the key ON and wait until the brake pump stops (the amount of time it takes for the pump to stop is also a clue, very short or very long run time is bad)."

Thanks you for providing the test. I think it helps a lot of people who just want to know if they need a new accumulator but don't know how to read the results of the entire brake test found elsewhere on the net.

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Guest Mc_Reatta

This evidence from the newly installed accumulators seems to give more credence to the belief that the new accumulators that you can buy are really new old stock (NOS) manufactured years ago and stored in inventory ever since.

Since rubber products and items containing compressed gases are subject to deterioration over time, it would be expected that they will not function as well as they would when they were freshly made. This seems to be born out by the performance (or lack thereof) that people are seeing when replacing their old accumulators.

Funny how as the available stock goes down we pay higher prices for one, and we will only be rewarded by a marginal increase in performance over the one it replaces, and it won't last very long either.

Has anyone tried one from the company that is marketing a new brake system that Barney uncovered a while back that had new accumulators available.

ABS Power Brake Inc Orange CA 714-771-6549

It might be time to make the switch if they will fit and function better then these NOS ones do since the price difference is getting to be a wash.

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