How to disconnect ABS on 88 to test for fault

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mitchcornacchia

How to disconnect ABS on 88 to test for fault

Post by mitchcornacchia »

I think after replacing all my brake components I still have a brake dragging issue I want to disable the ABS system how can this be achieved??
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dwcains
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Post by dwcains »

You can pull the fuse(s). You can also try an IR heat sensor gun to see if one rotor is hotter than its mate on the same end of the car. It's a nice tool to have, and they can be had for $25 or so on Amazon.
Dean
Lutz, FL

'85 635 CSi Euro #9402254
'87 Spider Veloce
'92 Spider Veloce
'08 350Z

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Chris Wright

Post by Chris Wright »

I don't think it would be likely that the ABS would cause dragging. The ABS never applies the brakes, it can only release the brake pressure when it detects a locked brake. Other wise the brake lines run straight through the ABS.
Have you checked the rubber brake hose between the chassis and caliper? They can collapse internally and cause problems.
mitchcornacchia

new everything

Post by mitchcornacchia »

Master Cylinder, brake bomb, hoses, rotors, pads, calipers.
mitchcornacchia

ABS releases brake pressure rightttttt....????

Post by mitchcornacchia »

There it is if the ABS isn't releasing brake pressure totally the brakes will drag right??? So... I should be able to disconnect the ABS and see what happens.
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hornhospital
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Post by hornhospital »

No, they will NOT drag. You are misinterpreting what the ABS does. The ABS only releases/pulses the system when the wheel speed sensors interpret that the tires are losing traction under braking. They have no means of applying or holding the brakes. If the ABS malfunctions it cannot hold the brakes in applied mode. Can't happen. Disconnecting the ABS will tell you nothing.
Ken Kanne
'84 633CSi "Sylvia"; '85 635CSi "Katja";'85 325e "Hazel Ann"; '95 M3 "Ashlyn"
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Brucey
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Post by Brucey »

as suggested above do check that the brake is actually dragging and that it isn't something else slowing the wheel somehow. Is it one brake or more than one?

I don't think the ABS can cause this fault....but the brake servo might, if it applies a residual force to the MC, or doesn't release fully for some reason.

cheers
~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
mitchcornacchia

thanks gentlemen got it!

Post by mitchcornacchia »

Thanks again I'll keep searching for the culprit!
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