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Teves ABS Pump never stops


Aztec62

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Hello,

 

now that I have the rear axle back in the car, I was able to bleed the brakes.

I did that just like explained in the service manual.

I have used DOT 3 fluid (hard to get over here).

Manual bleeding the front brakes, the rear brakes were done with the help of the Teves ABS pump.

Worked great and all air is out of the system.

 

Only trouble is the ABS pump never stops.

I let it run for two or three minutes, no stop. I think it would run for ever.

 

I understand that even with a bad accumulator, the pump should stop when the accumulator is completely filled with brake fluid and pressure is OK.

I can see how the brake fluid level drops when the accumulator gets charged and how it rises when the system is dpressurized by pumping the brake pedal.

 

I did some tests for the ABS pressure switch.

The switch pin`s continuity when accumulator is pressurized is correct.

Depressurized there is no continuity between terminals B and D, rest of the tests were OK.

According to the wiring diagram, the continuity between pin`s B and D when depressurized will turn the "Brake" warning light on, that is all.

I think the pressure switch is OK as far as turning the pump on/off to keep accumulator pressure at a certain level is concerned.

 

What else could it be?

A weak pump?

Still the pressure switch?

Or bad accumulator?

 

I have searched the forum but was unable to find an answer to my problem.

 

I do not have any BCM codes, the ABS system displays codes related to the wheel sensors only.

 

Any help is very welcome

 

edit:

Been thinking about it some more and I have come to the conclusion it could be a defective ABS pump motor relay.

Will check.

 

 

Have fun,

Henning

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If there is brake fluid on the connector side of the pressure switch the switch is no good.

When I had an issue with my pump/motor it was the motor not running. After I swapped in a different pump/motor [with an untested pressure switch and accumulator] the repacement pump/motor wouldn't run. I swapped in a known good switch and it ran like it should [the untested accumulator was good]. the original motor was all worn out with bad brushes etc.

I have not dealt with your situation as yet, but from what I have read from others experience, that if the bladder of the accumulator is no good the pump cannot build pressure and will run because there is no pressure for the switch to read to turn off the motor.

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The pump should create enough pressure for the switch to shut it down when the set limit is reached, regardless

of the accumulator.

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I would unplug the pressure switch after the pump has been running long enough to build pressure. If the pump continues to run with the pressure switch unplugged the relay is almost certain to be the problem.

 

Did you purge the air as described in this tutorial before bleeding the brakes? How To Purge Air From The Brake Pump

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Ronnie,

the pump motor stops when I unplug the pressure switch, so the relay is good.

No brake fluid on the connector side of the pressure switch.

I did purge the air as described.

 

I will try to get a new pressure switch, but they are rather expensive.

Anyone have a known good example?

 

The Teves Mk.II Anti Lock Brake System is made in Germany and has seen use in a large variety of cars.

Alfa Romeo, Ford, Jaguar (XJ40), Volkswagen and probably many more manufacturers used them for cars sold in Europe around 1990.

Used Teves Mk.II are available from such cars, but they are not exactly the same as the one used in the Reatta.

New parts are not available here.

Fixing a malfunctioning Teves Mk.II is just as difficult in Germany than it iis in the USA.

 

 

Henning

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I have two new switches and 7-8 known good used ones. Let me know if you want one as well as how to ship to Germany.My email is;

lemke1044@aol.com

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Dave,

I have made some more tests today and I am now leaning towards a weak pump as reason for the pump not stopping.

The pump was running all the time when I got the car, so nobody knows how much time the pump ran without stopping.

The pump should not run more than two minuets constantly, then it should cool down for ten minutes.

I am pretty certain the pum has been overstressed.

 

Let me get a Teves Mk.II unit I can pick up here from another car. I might be able to use the pump for my Reatta Teves Mk.II unit.

 

Thanks for your support, I might be coming back to you.

 

Henning

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I also have three pump/motors and I will leave a switch on it for you. The accumulator ball that would be on it would be no good.

So to be clear one pump/motor with a working switch. No ball.

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I ran into the same problem only I checked on a reman unit because a used unit could wind up acting the same. The price I got was $960.00 dollars. I refuse to pay that so what I did was I got hold of a powerbrake system out of a 1991 Chevy S-10 with the proportioning valve attached and installed it in place of the Tevis System, I have to tell you I like the way it performs much better then the old system did when it was in good working condition.

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Could you give us the details on what you had to do to install the S-10 power brakes. Does the proportioning valve for it just use three brake lines like the Reatta has or did you have to do something with the brake lines to make it work?

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  • 4 weeks later...

I think I have discoverd the reason why the ABS pump of my 1990 Reatta never stops:

When I replaced the old pump with an identical pump from another Teves Mk.II,  I removed the flexible hose which connects the pump body with the fluid reservoir.

I expected the fluid reservoir would drain, but that did not happen.

Further investigation revealed that there is a filter in the reservoir just above the outlet for the pump.

 

Anybody ever tried to replace that filter or ran into a clogged filter?

 

Despite my findings,  I put all back together again.

I topped up the reservoir with DOT 3 fluid.

I tried to purge the pump of any trapped air according to Ronnies instructions.

Small wonder it was impossible. Because the pump got no fluid, nothing happened.

I have separated the pump motor from the pump again and found both motor and pump turnig freely

 

By the way, I have two accumulator balls here, one is from a 1991 Germany-build Ford Scorpio, the other is from my Reatta.

On both it does not say "Made in Germany".

 

Henning

Bremen, Germany

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Henning, it's unclear to me if the filter was your problem or just a pump full of air. What fixed it? Thanks for the tip on the filter in the reservoir! I didn't know that.

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Henning, it's unclear to me if the filter was your problem or just a pump full of air. What fixed it? Thanks for the tip on the filter in the reservoir! I didn't know that.

 

Ronnie,

It is not fixed. No fluid is going from the full reservoir to the pump.

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That's odd. Could there be a vent hole in the cap that's blocked? Have you tried blowing back through the line that goes to the pump toward the reservoir? Perhaps that would determine if the filter is blocked.

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went to my garage today to dig deeper into the problem.

I have taken the liberty to remove the brake fluid reservoir from my spare Teves unit and cut it open where the filter should be. The Teves unit is from a German Ford Scorpio Mk.I. It is almost identical to the Reatta unit.

 

Three findings:

- Yes, there is a filter inside!

- Yes, it is not replacable!

- Yes, it can get blocked. It was on my car.

 

I have attached a longer hose to the reservoir of my Reatta Teves unit and by blowing into the hose I was able to unblock the filter. Fluid now flows freely to the pump. Before there were only drops coming.

The pump still builds no pressure, no fluid flowing when I try to purge the air out of the pump with Ronnies method.

But that is another story at this moment. My Teves units tries everything not to work ?

 

Here are a few pics:

 

20170816_163206.jpg

 

20170816_163323.thumb.jpg.69ddc948fd8584e39cffabd0396f2423.jpg

 

20170816_163216.thumb.jpg.221b8730f795f085f581e981ab51a059.jpg

 

20170816_163609.thumb.jpg.4a23f512b83d3c3ce35696da1ad61782.jpg

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Since you have two Teves units you might want to modify a reservoir cap so you can attach a hose to it and apply a very small amount of pressure in the reservoir to help push the fluid out the line going to the pump. Blowing into the hose with your mouth might be all that is needed. That extra force might help purge air from the pump to prime it with fluid.

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Thanks Ronnie!

I will try it.

 

Tried.

Does not help.

Pump still delivers no pressure.

Will try other pump tomorrow. 

 

Henning

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