ABS question and problem

[Guest]

There's a guy willing to rebuild the ABS components for around $750 (see earlier posts on previous pages/archive). If you can afford it, I would repair the ABS as that system, when functioning, is a good thing to have.<P>There have been others (including a mechanic I went to) who recommended eliminating the system altogether. Of course, this involves more than ripping out components as the car has multiple sensors and computers that expect to have signals coming in from that quarter.<BR>

[Gary Frank]

1990 Red convertible with 65k miles<BR>Question: <BR>1. How long shold it take for the pump to make the pressure switch after the car has been off for a day or so.<BR>2. When you are sitting still with motor at an idel and you press the brake pedal hard to the floor,it bottoms out and the ABS warning lith comes on and goes off.<BR>3. My brakes are not hard at all, but car stops okay. Late last night with no traffic at a speed of 70 mph I tested the braking and ABS capabilities of the car and found the following.<BR>4. Is there an easy way to check the performance of the accumulator and pump. I will check the manul and if you know of a specific page or section please inform me.<BR>A. The brake pedal went all the way to the floor, bottomed out (needed more brakeing)<BR>B.The front tires sqeeled, could not tell if the locked up.<BR>C. This was not fun but I tried it agin and had the same results. I live in the country and enjoy the back roads, (yes we have DEER)may never have to use my brakes in this manner but it seems they are losing their strenght.<BR>I have only put 6K miles on the car and have never had a brake problem excpet it seems like it takes to long for the air pump to turn out the ABS light and the pedal has never been hard.<BR>Note: my 1990 Riviera does not have the ABS option and the brakes work great, would it be possible to use this system and remove the complete ABS.

[Guest]

To answer your first question: It takes about 25 seconds (give or take a few) for the brake sensor lights to go out when I first start my '90. The first owner never put the car in gear until all indicators went out, and I do the same, so that is why I know how long it takes. I don't know if that makes a difference with anything, but I figure my life is not so rushed that I can't wait for it.

[Guest]

With the disclaimer that I'm surely not a professional at this, it sounds like the accumulator. At idle, you press the pedal. Without a good accumulator, the system pressure drops, the pedal goes to the floor and the ABS light comes on. The pressure switch senses this, turns on the pump and re-pressurizes the system. (listen under the hood when you first start your car for the relay click and the pump's operating noise). The ABS light then goes out. As far as a test of the accumulator, all I have heard of is a shop test for pressure drop. Be VERY careful if you decide to unscrew the accumulator sphere and replace it yourself (though it's not complicated). With the key out of the ignition, you have to pump the brake pedal 25 times or so to remove all residual system pressure before removing the accumulator. My accumulator says it is charged to 2500 psi or so.

[Guest]

I you have the manual, read the entire anti-lock section carefully. You will find they consider the pedal going to the floor while sitting still to be "normal". You may have a bad accumulator, as the light should not come on, even when this "to the floor" is taking place. I have found, from my own testing, that you must really jump on the brakes hard to make the anti-lock activate. This is on smooth dry roads. If you were brought up (like I was) to apply the brakes smoothly and progressively, the brakes on the Reatta seem to respond poorly to this treatment. For normal, planned braking, this works okay, but if you are in the process of braking and decide to stop even more quickly, the brakes do not really seem to increase in stopping power, the brake pedal simply depresses further. If you are doing your own testing, really slap the brakes on hard, do not get into them slowly. If the system is operating properly, the brake pedal should go very hard and actually rise toward you. You may feel a pulsation in the pedal. The car will stop VERY quickly. You will probably get "chirping" from your tires. No brake or antilock lights should come on. <P>------------------<BR>Hal, btk@vbe.com

[Guest wally888]

Take car to Buick dealer.Tell them to remove accumulator,install adaptor(has a GM part #) and test accumulator. The manual covers this fully and it is very difficult to be sure if you have a bad accumulator w/o this test.I and many others have been ripped off by being told we have bad accum.'s, being charged big bucks then having to find the real trouble.<BR> A new accum. can be bought for $85 + shipping and is very easy to replace but settle on a price before test as they will probably want $60 to test!$160 or so would be good price for test and,if needed,replacement.<BR> Bet above is shocking to some!!!