Brakes Lock and Won't Let Go, 94 Grand Voyager - Help before they get me killed.

On wet days the rear brakes will make a loud clunk sound and lock up the
first few times they are applied. When the brakes lock, of course I
instinctively release the pedal, but the brakes remain locked until the
van comes to a complete stop. Sometimes they release immediately upon
coming to a stop. Other times, they won't let go for upwards of 30
seconds. I bought the van used and was told that the ABS pump had been
out for years. The ABS fuse had also been pulled. However, the dealer
says the ABS system cannot be fully disabled (whatever that means).

Everything I have read says that the first time the brakes are applied,
the ABS system does a self test (which may be accompanied by a clunk
sound) and can disable itself if the test isn't nominal, thereafter
working as a conventional brake system. If the ABS system can disable
itself, why can it not be permanently disabled? If, in fact, it is
disabled, then why don't the brakes release? The dealer attributed it
to the "front springs and 'something' in the ABS system," whatever that
means.

I've seen the following causes of brakes locking on this and related
vehicles (including the Dodge Caravan)...

1) Sticky Calipers
2) Sticky Pistons
3) Sticky Master Cylinder
4) Some kind of restriction in the brake fluid lines
5) Sticky ABS relay

Anyone seen these symptoms before or have any ideas?

By the way, the occurence appears to have more to do with wet roads that
any moisture in the system, since it is independent of whether or not
the van was in the garage or left outside, but I could be wrong on this.
Maybe it's both.

Thanks.

On Fri, 02 Jul 2004 14:48:08 -0500, Jim Ashburn
> wrote:

>On wet days the rear brakes will make a loud clunk sound and lock up the
>first few times they are applied. When the brakes lock, of course I
>instinctively release the pedal, but the brakes remain locked until the
>van comes to a complete stop. Sometimes they release immediately upon
>coming to a stop. Other times, they won't let go for upwards of 30
>seconds. I bought the van used and was told that the ABS pump had been
>out for years. The ABS fuse had also been pulled. However, the dealer
>says the ABS system cannot be fully disabled (whatever that means).
>
>Everything I have read says that the first time the brakes are applied,
>the ABS system does a self test (which may be accompanied by a clunk
>sound) and can disable itself if the test isn't nominal, thereafter
>working as a conventional brake system. If the ABS system can disable
>itself, why can it not be permanently disabled? If, in fact, it is
>disabled, then why don't the brakes release? The dealer attributed it
>to the "front springs and 'something' in the ABS system," whatever that
>means.
>
>I've seen the following causes of brakes locking on this and related
>vehicles (including the Dodge Caravan)...
>
> 1) Sticky Calipers
> 2) Sticky Pistons
> 3) Sticky Master Cylinder
> 4) Some kind of restriction in the brake fluid lines
> 5) Sticky ABS relay
>
>Anyone seen these symptoms before or have any ideas?


I had a Ford that behaved almost identically. The problem was
brake lining material, dust, rust, etc. built up inside the rear
drums. Every time it got damp, the rear brakes would lock
uncontrollably until dried out.
Remove the drums and clean out all the dust. Blow off brake
components with compressed air, and maybe lubricate the contact points
between the shoes, backing plates, and cylinder rods. (Don't breathe
the dust. There's still asbestos in some brake lining material).
Replace the drums and adjust brakes as necessary.

On Fri, 02 Jul 2004 14:48:08 -0500, Jim Ashburn
> wrote:

>On wet days the rear brakes will make a loud clunk sound and lock up the
>first few times they are applied. When the brakes lock, of course I
>instinctively release the pedal, but the brakes remain locked until the
>van comes to a complete stop. Sometimes they release immediately upon
>coming to a stop. Other times, they won't let go for upwards of 30
>seconds. I bought the van used and was told that the ABS pump had been
>out for years. The ABS fuse had also been pulled. However, the dealer
>says the ABS system cannot be fully disabled (whatever that means).
>
>Everything I have read says that the first time the brakes are applied,
>the ABS system does a self test (which may be accompanied by a clunk
>sound) and can disable itself if the test isn't nominal, thereafter
>working as a conventional brake system. If the ABS system can disable
>itself, why can it not be permanently disabled? If, in fact, it is
>disabled, then why don't the brakes release? The dealer attributed it
>to the "front springs and 'something' in the ABS system," whatever that
>means.
>
>I've seen the following causes of brakes locking on this and related
>vehicles (including the Dodge Caravan)...
>
> 1) Sticky Calipers
> 2) Sticky Pistons
> 3) Sticky Master Cylinder
> 4) Some kind of restriction in the brake fluid lines
> 5) Sticky ABS relay
>
>Anyone seen these symptoms before or have any ideas?


I had a Ford that behaved almost identically. The problem was
brake lining material, dust, rust, etc. built up inside the rear
drums. Every time it got damp, the rear brakes would lock
uncontrollably until dried out.
Remove the drums and clean out all the dust. Blow off brake
components with compressed air, and maybe lubricate the contact points
between the shoes, backing plates, and cylinder rods. (Don't breathe
the dust. There's still asbestos in some brake lining material).
Replace the drums and adjust brakes as necessary.

Thanks, Fly.

I'll give it a shot.

By the way, does anyone have any experience bypassing an ABS modulator?
What will I need to fork the lines from the two master cyclinder to go
to each pair of wheels? I'm looking at this since my other lead is that
the check valves in the modulator may be inhibiting the release of brake
fluid pressure, even though the ABS system is disabled (i.e., the fuse
has been pulled).

Later.

In article >,
the fly > wrote:

> On Fri, 02 Jul 2004 14:48:08 -0500, Jim Ashburn
> > wrote:
>
> >On wet days the rear brakes will make a loud clunk sound and lock up the
> >first few times they are applied. When the brakes lock, of course I
> >instinctively release the pedal, but the brakes remain locked until the
> >van comes to a complete stop. Sometimes they release immediately upon
> >coming to a stop. Other times, they won't let go for upwards of 30
> >seconds. I bought the van used and was told that the ABS pump had been
> >out for years. The ABS fuse had also been pulled. However, the dealer
> >says the ABS system cannot be fully disabled (whatever that means).
> >
> >Everything I have read says that the first time the brakes are applied,
> >the ABS system does a self test (which may be accompanied by a clunk
> >sound) and can disable itself if the test isn't nominal, thereafter
> >working as a conventional brake system. If the ABS system can disable
> >itself, why can it not be permanently disabled? If, in fact, it is
> >disabled, then why don't the brakes release? The dealer attributed it
> >to the "front springs and 'something' in the ABS system," whatever that
> >means.
> >
> >I've seen the following causes of brakes locking on this and related
> >vehicles (including the Dodge Caravan)...
> >
> > 1) Sticky Calipers
> > 2) Sticky Pistons
> > 3) Sticky Master Cylinder
> > 4) Some kind of restriction in the brake fluid lines
> > 5) Sticky ABS relay
> >
> >Anyone seen these symptoms before or have any ideas?
>
>
> I had a Ford that behaved almost identically. The problem was
> brake lining material, dust, rust, etc. built up inside the rear
> drums. Every time it got damp, the rear brakes would lock
> uncontrollably until dried out.
> Remove the drums and clean out all the dust. Blow off brake
> components with compressed air, and maybe lubricate the contact points
> between the shoes, backing plates, and cylinder rods. (Don't breathe
> the dust. There's still asbestos in some brake lining material).
> Replace the drums and adjust brakes as necessary.

Thanks, Fly.

I'll give it a shot.

By the way, does anyone have any experience bypassing an ABS modulator?
What will I need to fork the lines from the two master cyclinder to go
to each pair of wheels? I'm looking at this since my other lead is that
the check valves in the modulator may be inhibiting the release of brake
fluid pressure, even though the ABS system is disabled (i.e., the fuse
has been pulled).

Later.

In article >,
the fly > wrote:

> On Fri, 02 Jul 2004 14:48:08 -0500, Jim Ashburn
> > wrote:
>
> >On wet days the rear brakes will make a loud clunk sound and lock up the
> >first few times they are applied. When the brakes lock, of course I
> >instinctively release the pedal, but the brakes remain locked until the
> >van comes to a complete stop. Sometimes they release immediately upon
> >coming to a stop. Other times, they won't let go for upwards of 30
> >seconds. I bought the van used and was told that the ABS pump had been
> >out for years. The ABS fuse had also been pulled. However, the dealer
> >says the ABS system cannot be fully disabled (whatever that means).
> >
> >Everything I have read says that the first time the brakes are applied,
> >the ABS system does a self test (which may be accompanied by a clunk
> >sound) and can disable itself if the test isn't nominal, thereafter
> >working as a conventional brake system. If the ABS system can disable
> >itself, why can it not be permanently disabled? If, in fact, it is
> >disabled, then why don't the brakes release? The dealer attributed it
> >to the "front springs and 'something' in the ABS system," whatever that
> >means.
> >
> >I've seen the following causes of brakes locking on this and related
> >vehicles (including the Dodge Caravan)...
> >
> > 1) Sticky Calipers
> > 2) Sticky Pistons
> > 3) Sticky Master Cylinder
> > 4) Some kind of restriction in the brake fluid lines
> > 5) Sticky ABS relay
> >
> >Anyone seen these symptoms before or have any ideas?
>
>
> I had a Ford that behaved almost identically. The problem was
> brake lining material, dust, rust, etc. built up inside the rear
> drums. Every time it got damp, the rear brakes would lock
> uncontrollably until dried out.
> Remove the drums and clean out all the dust. Blow off brake
> components with compressed air, and maybe lubricate the contact points
> between the shoes, backing plates, and cylinder rods. (Don't breathe
> the dust. There's still asbestos in some brake lining material).
> Replace the drums and adjust brakes as necessary.

Jim,

Take this van to the dealer. That ABS system has a lifetime warranty.
My dealer replaced the ABS pump and some other thing (accumulator
maybe) to my 93 Grand Caravan with over 200K miles. This was a
thousand dollar repair job that kept this van from going to the scrap
yard.

Jim,

Take this van to the dealer. That ABS system has a lifetime warranty.
My dealer replaced the ABS pump and some other thing (accumulator
maybe) to my 93 Grand Caravan with over 200K miles. This was a
thousand dollar repair job that kept this van from going to the scrap
yard.

Lifetime Warranty? Sign me up! LOL Good one! Lifewtme Warranty!
"93GrandCaravan" > wrote in message
om...
> Jim,
>
> Take this van to the dealer. That ABS system has a lifetime warranty.
> My dealer replaced the ABS pump and some other thing (accumulator
> maybe) to my 93 Grand Caravan with over 200K miles. This was a
> thousand dollar repair job that kept this van from going to the scrap
> yard.

Lifetime Warranty? Sign me up! LOL Good one! Lifewtme Warranty!
"93GrandCaravan" > wrote in message
om...
> Jim,
>
> Take this van to the dealer. That ABS system has a lifetime warranty.
> My dealer replaced the ABS pump and some other thing (accumulator
> maybe) to my 93 Grand Caravan with over 200K miles. This was a
> thousand dollar repair job that kept this van from going to the scrap
> yard.

"93GrandCaravan" > wrote in message
om...
> Jim,
>
> Take this van to the dealer. That ABS system has a lifetime warranty.
> My dealer replaced the ABS pump and some other thing (accumulator
> maybe) to my 93 Grand Caravan with over 200K miles. This was a
> thousand dollar repair job that kept this van from going to the scrap
> yard.

Umm...no..it does not....
Sorry.
SOME, IIRC, had a recall..but no freaking lifetime warranty..