Advice Needed! Anyone have this happen??? (Pump not building pressure)

[MarkV]

So I need your Advice! Long story at the bottom, but the pump didn't pump on the reatta, it kept running. The car sits alot and I charged up the battery because we hadn'  driven it in a few weeks. Anyway worked on it, replaced the pressure switch and the accumulator with good used ones, still gave the same problem both brake lights pump running no pressure. Did this across two days Now a week later I jumped into the car and guess What? All works as it should. Needless to say I'm a bit perturbed. I bought a working used teves unit. Im wondering if I should just go ahead and replace mine anyway. I don't like something working than not working and then working magically again. However if the problem is fixed it's fixed. Im wondering if it took a while for the pressure switch or accumulator to click in? I know the accumulator has to fill maybe it needed more time than I have it? I have a new hydrac from spinning wheels on the way. I have done panic stops, everything seems fine.

 

"So I jumped into my wife's 88 reatta and the abs is not pressurizing no movement of fluid, nothing. The motor is continuously running. I swapped out the accumulator, pressure switch and the relay still the same still running no brakes pedal as hard as a rock all brake lights on. I'm thinking it is the pump motor maybe the brushes are worn? It also has a rubber hose under the accumulator compared to my 89 that has a steel line. "

 

[Barney Eaton]

Working thru the logic of the Teves system......

*  If the pump is running the pressure switch is sending 12v to the relay and on to the pump.

*  why no pressure.......some possibilities.....(1)either the pump is so bad it is not creating pressure (2) maybe no fluid is getting to the pump (3) the pressure relief valve is stuck open, so no pressure builds.

by disconnecting the hard line that runs from the pump housing to the booster, you could see if the pump is moving fluid.  To do this you would probably need to remove the accumulator...unscrew the booster end completely and

swing the hard line out to the front so you could attach a hose and run the hose into a water bottle.  The pump can create high pressure but the volume is fairly low, so do not be too concerned that you will fill the bottle in seconds.

This would give you a hint if fluid is coming out that line.....if it is, then put you finger over the end and you should not be able to stop it....unless the pressure relief valve is stuck.

 

The other comments would be.....it almost has to be one of the above, because (1) if the accumulator bladder was ruptured, pressure would build immediately and the pump and lights would shut off...but as soon as you touch the pedal the pump would start.

If the accumulator bladder is in tack but the precharge is low it could take a long time (60 seconds +) to charge the accumulator and the pressure pump to shut off the motor.....and the lights would go out.  If the high pressure shut of point on the pressure switch was bad the pump would continue to run, the lights would go out and you would have boost....but the pump running at very high pressure would probably burn up the motor.

[89RedDarkGrey]

What / how would the system act if air bound? Can the pump make enough air pressure to satisfy the switch? Does air pressurize earlier / easier than brake fluid?

 

I would remove the passenger rear banjo bolt at caliper (or bleeder screw), hold down brake pedal 1", and with key on- exchange 1 quart of fluid. Reinstall screw (or bolt) with pump running. Key off, pump pedal 25 times. 

 

Repeat above procedure.

 

After 25 pedal pushes- check & top off fluid. Key on, examine fluid drop amount.

[DAVES89]

I like Barney's response. All the testing should be at the pump as that is where the issue is...

[89RedDarkGrey]

5 hours ago, DAVES89 said:

I like Barney's response

 

Which one? He's kind of all over the map here.

 

5 hours ago, DAVES89 said:

All the testing should be at the pump as that is where the issue is...

 

I agree.

 

I was merely asking and speculating- what would be the symptoms and effects of the pump being air bound?

 

And then I explained what I would do to try to remedy the original problem.

 

It's hard to give advice on braking systems in an online Forum. People tend to tiptoe through the minefield, because of the nature of the topic. Incorrect or misinterpreted information about polishing tail lights won't cause bodily injury or death- so people usually steer clear of giving or receiving advice about brakes. I don't blame them at all.

 

[Barney Eaton]

Maybe I should have said more.......the problem is you never know what the owner has already done and what their level of mechanical ability happens to be.

Over time, if you have read my responses on brake problems, I try to suggest flushing the system.  Again we don't know any more about the vehicle than what the owner posts.

Many of our Reattas are running around with the brake fluid that was installed at Lansing......26+ year old fluid ...saturated with water, rust, and other contamination.  Get the old fluid out,

new DOT3 is inexpensive.

[MarkV]

Fluid flushed 2 years ago along with an nos accumulator and pressure sensor

[MarkV]

I drive the car about 30 miles yesterday and all was fine. Im going to flush the fluid and replace the accumulator with a hydrac one from spinning wheels. I also have to get the rotors turned which is another issue. The car sits alot unfortunately and we drive it once a month. It is possible air was in the system? Who knows. 

[Barney Eaton]

You could have air in the system BUT.....the Teves ABS is like 2 different systems hooked together and use the same fluid.

The BOOST part of the system gives you the POWER part of power brakes.....air rarely get trapped so that is seldom an issue in the boost part.

The BRAKE part is almost like any other brake system....if you get air in it stopping will be affected and you may have a funny pedal feel.

[89RedDarkGrey]

Maybe THIS PROCEDURE is what I was referring to?

[Digger914]

On ‎11‎/‎5‎/‎2017 at 1:34 PM, MarkV said:

So I need your Advice! Long story at the bottom, but the pump didn't pump on the reatta, it kept running. The car sits alot and I charged up the battery because we hadn'  driven it in a few weeks. Anyway worked on it, replaced the pressure switch and the accumulator with good used ones, still gave the same problem both brake lights pump running no pressure. Did this across two days Now a week later I jumped into the car and guess What? All works as it should. Needless to say I'm a bit perturbed. I bought a working used teves unit. Im wondering if I should just go ahead and replace mine anyway. I don't like something working than not working and then working magically again. However if the problem is fixed it's fixed. Im wondering if it took a while for the pressure switch or accumulator to click in? I know the accumulator has to fill maybe it needed more time than I have it? I have a new hydrac from spinning wheels on the way. I have done panic stops, everything seems fine.

 

From the color of your brake fluid, my best guess is you had enough moisture accumulation to freeze a valve half open. Didn't mention when I first spotted this picture with the dirty fluid because for this to happen you need to be in the right climate, the brakes need to sit unused long enough for the moisture to separate from the fluid and  you need  enough moisture in the fluid to plug a port or hold a valve open  when it freezes.  Don't know what part of the country you're in, but what you're describing here sounds like this could have happened,