My brother has a 2001 330T which occasionally has a partially seized front
brake caliper - the disc gets very hot. But on checking after fighting to
remove the pads, the piston moves as normal as does the caliper on the
slides. He's had BMWs for several years and does pretty well all his
maintenance so is quite familiar with the brakes. But this is his first
one with ABS. Could it be an ABS issue? Or any other likely causes? I sort
of agree with him that calipers don't seize like this and sort themselves.
*OK, who stopped payment on my reality check?
Dave Plowman firstname.lastname@example.org London SW
Maybe a bad flexible brake hose that's failed inside. The old E24/E28
did this a lot on the rear hoses for some reason.
Maybe when you remove the caliper to move the piston you're flexing the
hose and curing the problem.
Who needs a life when you've got Unix? :-)
Email: email@example.com, John G.Burns B.Eng, Bonny Scotland
If the ABS is actually activated due to a hard stop, then maybe it can cause
the fluid pressure to remain high on one corner of the car. Maybe. But if
the ABS is not actively being used -- very aggressive stops at the edge of
brake lock -- then the system is passive (unused) and it will not hold
pressure high in one place. Remember, the job of ABS is to release brake
pressure to a corner to prevent brake lock, then build that pressure again
instantly so that the wheel slows to the point of stopping, then release
again. Repeat as needed.
Given the fact that the duty of ABS is to release brake pressure, it does
nothing unless brake pressure needs to be released. If the car is driven in
a moderate manner and not on the edge of control, the ABS should never play
a role in anything.
The OP is complaining that the brakes do not release. ABS will not cause
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