ABS Braking not working


Old 12-31-02, 12:35 PM
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ABS Braking not working

The vechile is a 1990 Olds Cutlass SL, 3.1 engine, auto.

The problem is that the accumulator pump continues to run draining the battery.

I have changed the accumulator and this stopped the drain for about a month. Now its acting the same as before.

With the car running there sounds like a short brust from the horn but its not the horn. In fact the master cyclinder vibrates as if pressure is being built up than release throught the brake fluid reservoir.
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Old 12-31-02, 02:39 PM
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What does your service manual have to say?

ABS brakes are NOT something to fool around with without the proper tools, procedures and know how. Your life could depend on it.
Old 01-01-03, 06:13 AM
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Especially this system. It sounds like you have the system that keeps the system at very high pressures at all times (like at over a thousand psi). This is certainly nothing to fool around with. (You changed the accumulator? Cool!)

You don't have any fluid leaking externally? If not, you almost certainly have an internal leak somewhere. Somewhere between the accumulator and the reservoir (I imagine there's a check valve in there somewhere). If you are not losing fluid, then it's probably leaking the pressure right back into the reservoir.

**Ching ching!**

I have no experience working on this type of abs system, but my guess is it's time to replace the pump assembly, or if you are lucky a check valve might be replaceable.
Old 01-01-03, 08:26 AM
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Now that I've looked at this post again, I'm shying away from the check valve idea.

If it was a check valve then your pump would cycle on and off.

If it's continuously running, AND you are NOT losing any fluid, then I think the pump it's self just isn't working right.

**Big Ol' Ching!**

This system is just so dangerous you might want to break down and take it in to have it looked at. If there's some sort of pressure sensor (shich I'm sure there has to be) it might not be working properly. Imagine that. If the pressure sensor doesn't know the system is charged up and the pump keeps running and running....... Uhoh! Hopefully they designed some sort of bypass system so it wouldn't just explode if this ever happens.

This kind of abs system simply can't be ignored. It's not like you have the luxery of having a normal braking system with master cylinder and all. If this pump assembly fails then you just have no brakes at all. (Parking braks perhaps)

I'm sure glad they didn't use this system for very long.
Old 01-02-03, 08:10 AM
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Well, from the replies I am going to check two items.
The pressure switch and the relief value in the brake fluid reservoir.

Thanks for the help.

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