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brake failure


harry yarnell

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Today I had the dreaded brake/antilock lights come one while driving today. What to do, what to do. Do I pull over and restart, hoping the relay will unstick? Call a rollback? Take my chances? I did the later. Figuring I had 5 or so good stops left before the pressure went to zero and the pedal got rock hard. Kept an eagle eye out for forward traffic, used the shifter to downshift, checked the parking brake, and nursed it. Each application of the brake I thought would be my last, but each brake was there, as if nothing was wrong.. I made it home with probably 15 applications of the brake; no problems.

Back to the garage, and the the pumps running! And doesn't shut off. And it's HOT. Before I look in the manual, what do you guys think? Pressure switch stuck?

This is on a '90. The brake dash lights on a '90 are difficult to see in the daylight. I can see how folks would miss these warnings.

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Guest spongebob

rats..........................

the teves brake system..mine is leaking fluid...ive replaced the o-ring(psi sensor) and but a sealent on the threads, but im still getting a leak...should i just park over a rag??

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At least you gave more information than most.

Both lights on and the pump motor is running........

My thoughts....

* If it were a relay stuck on, I don't think the lights would be on.

* A bad pressure switch could send a signal to the controller that the pressure was low (when it is not) and also keep the pump running.

* A bad accumulator might cause the conditions, but you would think it would just cycle on/off rapidly.

* It could also be a bad connection at the pressure switch or relay.

* Not sure what condition the fluid level sensor gives... I may go to the garage and unplug mine just to see.

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Yes, could be a pressure switch that is not shutting off the pump but could also be a pump that isn't building up the pressure high enough to trip the pressure switch off.

A pressure gauge test will tell all.

Better drive the Toyota until the brakes are fixed.

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I checked my 1990 by unplugging the fluid level connector and the "BRAKE" light went out but the ABS light stayed on. However there are 4 pins and one set is for the BRAKE light to ground, so unplugging it would eliminate the BRAKE light.

Run Wally's tests......

If the pump is not building pressure, you can get a good idea by.....turning on the ignition and let the pump run 30 seconds or until it shuts off.

Turn off the ignition and pump the pedal..counting the pumps. The book says that the accumulator stores enough pressure for 25 stops. If you can get 10 before the pedal gets hard, the pump is working.

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Guest wally888

Harry, If the pump relay is bad/ contacts stay open sometimes/stay closed sometimes.................(you could switch Main and Pump) then if Pump Relay is intermittant you will get intermittant yellow light but pump will run normally if Main Relay is O.K.

I'd 1st just install new relays.

Let us know what #'s you are able to locate/buy?

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The pressure switch does not turn off the motor....it turns off the relay that turns off the motor. If the relay is stuck, the pressure switch will not turn it off and the motor will continue to run.

Start by switching the relays and unplug, and replug the connectors at the pressure switch, and fluid level sensor.

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  • 1 month later...

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