Brakes not working property

wingzeroac195

SCCoA Member
Guys, have a scary issue with the brakes on my 92 sc. about 2 weeks ago the brake light came on, i pressumed it was low on fluid since is been losing some for about a year, but when i filled some and went to work the light stay on and one time i tried to brake and it didnt do it, got scared. the the brake light went off and everything was fine. i had some fluid on the ground and i thought it was the arc pressure switch, so i remove it and plug it, that looks like is working but is still doing the same, i start the car, brake light on, start driving and brakes are good with the light on. suddenly no brakes and a humming noise, then brake pressure is back on and the light goes off after a minute. also when i brake the car pulls to the left. now it has new calipers and pads, gonna change the brake hose on thurs. but it has to be something else. yes i have the troublemaker brake system from the 89-92. i dont see no more leaks yet. fluid it up to level, so any ideas please.
 
Start here:

http://www.sccoia.org/articles/anti-lock-braking-system/

Just keep in mind that while that page discusses the general role the ignition switch plays in the operation of the ABS, it doesn't suggest that in some cases the ignition switch is the only thing that needs replacing.

Suspects list, not ranked:
- pump motor
- accumulator
- pressure switch
- ignition switch
- relay(s)
- loss of fluid resulting in air in the system

In your example of off/on pump, without the brakes being used, I'd wonder about the ignition switch first (ask me how I know).

Pulling to the left can mean worn suspension and/or hanging caliper and/or brake hose swollen inside where you can't see it.

I'd not drive the car until this is sorted. I'd do all the brake lines, then bleed the system, then test drive.

If it still pulls, continue inspecting the suspension.

If the brakes still act out, check/replace the ignition switch. If replacing the ignition switch doesn't cure the random fail, do the relay(s). If the relay's don't help, troubleshoot the pressure switch. If it's not the pressure switch, replace the accumulator. If it's not the accumulator, troubleshoot the pump. It it's not the pump, trade the car for a mule and shoot the mule.

Good luck.

Ken
 
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I'll go with that pretty much in that order.

One thing you can do to verify if its ignition switch, is to rock it fore/aft slightly when the dash lights come on. If the pump motor engages again and the lights turn off, then that definitely points to the switch. Next likely is, as noted, the relay.

you know what.. I'd say for the piece of mind, just go ahead and replace both the ignition switch and the relay. Both of these items are eventually going to wear out or break.

From there, it gets dicey.. if the pump is running a LOT, like everytime you press on the brakes, thats usually from a tired accumulator.. if its too often, then your pump motor will heat up and possibly trip its internal thermal switch. Only when it cools down will it start working again. So a new accumulator is a good idea as well.
 
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