Caravan: Both front calipers seized????

Nate Nagel > wrote:
>I remember doing a brake job on my ex's old Valiant and then going out
>of town again. I came back to visit a while later and ended up driving
>her car somewhere and we came to a stop light. As we sat at the light,
>the pedal slowly sank to the floor. I asked her if she was going to
>get the master cylinder replaced and she gave me a blank look... I
>asked her how long the pedal had been going to the floor like that, and
>she said "oh, a couple weeks" (facepalm)

So, did you break up because she was an idiot or are you a widower
for similar reasons?
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

On 12/19/2010 3:04 PM, Nate Nagel wrote:
>
> True dat
>
> I remember doing a brake job on my ex's old Valiant and then going out
> of town again. I came back to visit a while later and ended up driving
> her car somewhere and we came to a stop light. As we sat at the light,
> the pedal slowly sank to the floor. I asked her if she was going to get
> the master cylinder replaced and she gave me a blank look... I asked her
> how long the pedal had been going to the floor like that, and she said
> "oh, a couple weeks" (facepalm)
>
> nate
>

Your ex must have been charmed. My MC failed on me twice without
warning. Luckily there was a tree nearby to assist me in bringing my
Caravan to a rapid stop. The other car that this happened to was a Chevy
Cavalier. I didn't have a tree handy but was able to use the hand brake
to handle the braking duties. They say that the rear brakes only
provides 30% of the total braking force in a car but take it from me -
I'll 30% braking than 100% breaking anyday.

Replacing a master cylinder is one of the nicer jobs you can do on a
car. You just buy the part and your don't have to get all dirty and
mostly it's just a couple of bolts and 4 lines and you don't even have
to jack the car up. Whee!

On 12/19/2010 01:42 PM, Paul in Houston TX wrote:
> jim beam wrote:
>> On 12/19/2010 12:44 PM, Paul in Houston TX wrote:
>>> jim beam wrote:
>>>> On 12/19/2010 11:21 AM, Paul in Houston TX wrote:
>>>>> jim beam wrote:
>>>>>> On 12/19/2010 12:50 AM, Paul in Houston TX wrote:
>>>>>>> jim beam wrote:
>>>>>>>> On 12/18/2010 05:49 PM, Paul in Houston TX wrote:
>>>>>>>>> Programbo wrote:
>>>
>>>>>
>>>>>>> 2. Something the shop did to the calipers or bushings.
>>>>>>
>>>>>> swap in crappy ones? that's not probable.
>>>>>
>>>>> Nope. Was not even thinking that.
>>>>
>>>> how does "something the shop did" come into it then?
>>>
>>> Although I think it unlikely, we don't know what the shop
>>> did. Did they allow the hub to pivot too far or dropping
>>> and pivoting thereby allowing #3 to happen?
>>
>> do you think it's likely or even possible for them to manage two
>> independent events that somehow caused this identically for both sides?
>
> Do you know for sure what is wrong with both front calipers?
> Is the problem the same for both?

you said, 'both front calipers "glowing red"'. so you tell me - is it
both?

and again, if it is both, what do you think is the likelihood of someone
managing to accidentally screw up both front calipers in the same way
and to the same extent?


>
>> in the mean time, have you done what i suggested and checked the pedal
>> free travel?
>
> Don't know, not my vehicle.

psychic vehicle diagnostics with chinese whispers thrown in - my
favorite combination.


> My next Guess is bad vac booster.

if it's vacuum, the brakes will be hard on right from engine start, not
'after about 20-30 minutes of city driving the brakes begin to
drag badly'.


>
>>>>>>> 3. Shop stretching the hose and rupturing them internally
>>>>>>> during the r&p replacement.


--
nomina rutrum rutrum

On 12/19/2010 01:39 PM, Paul in Houston TX wrote:
> Nate Nagel wrote:
>> On 12/19/2010 03:35 PM, jim beam wrote:
>>> On 12/19/2010 11:21 AM, Paul in Houston TX wrote:
>>>> jim beam wrote:
>>>>> On 12/19/2010 12:50 AM, Paul in Houston TX wrote:
>>>>>> jim beam wrote:
>>>>>>> On 12/18/2010 05:49 PM, Paul in Houston TX wrote:
>>>>>>>> Programbo wrote:
>>>>>>>>> Hello all. OK just to keep it short, my brother has a 1994 Dodge
>>>>>>>>> Caravan with the 3.0 engine and automatic transmission. This
>>>>>>>>> may or
>>>>>>>>> may not be relevant to what I am about to ask but at the
>>>>>>>>> beginning of
>>>>>>>>> last week he had the rack and pinion changed. Now he says when he
>>>>>>>>> drives after about 20-30 minutes of city driving the brakes
>>>>>>>>> begin to
>>>>>>>>> drag badly so that the van is hard to drive. He said last night it
>>>>>>>>> was
>>>>>>>>> so bad when he got home he saw both front calipers "glowing
>>>>>>>>> red". I
>>>>>>>>> just had time now to pull of the front wheels and had him pump the
>>>>>>>>> brakes and hold the pedal down and opened the bleeders and both
>>>>>>>>> had a
>>>>>>>>> strong fluid pressure so I know the master cylinder is working
>>>>>>>>> fine in
>>>>>>>>> that regard. My question is..Is it possible BOTH front calipers
>>>>>>>>> are
>>>>>>>>> going bad at the exact same time and if that's unlike what else
>>>>>>>>> could
>>>>>>>>> I look at as the cause? Thanks in advance
>>>>>>>>
>>>>>>>> Two bad calipers are possible.
>>>>>>>> Bad hoses that are frayed inside.
>>>>>>>
>>>>>>> how is that going to happen?
>>>>>>
>>>>>> 1. I was thinking that maybe they were almost freezing up already
>>>>>> but not noticed.
>>>>>
>>>>> maybe, but if the symptoms are as bad as you say, you should have
>>>>> noticed before the rack was changed.
>>>>
>>>> Maybe. Maybe not. People tend to look for things after work
>>>> has been done.
>>>
>>> you don't think you'd notice brake disks glowing red? i think i would.
>>> i'd notice the abysmal gas mileage too.
>>>
>>>
>>>>
>>>>>> 2. Something the shop did to the calipers or bushings.
>>>>>
>>>>> swap in crappy ones? that's not probable.
>>>>
>>>> Nope. Was not even thinking that.
>>>
>>> how does "something the shop did" come into it then?
>>>
>>>
>>>>
>>>>>> 3. Shop stretching the hose and rupturing them internally
>>>>>> during the r&p replacement.
>>>>>
>>>>> why do people so susceptible to this "ghost in the machine" argument?
>>>>> hoses are hollow rubber cylinders. any rupture goes external and you
>>>>> lose brake fluid. there's no internal componentry that can cause this
>>>>> effect. the only possibility is a twist in the hose causing a pinch.
>>>>> and that will be obvious if you take the wheels off and look.
>>>>
>>>> I have never seen this personally, but there is a lot on the web
>>>> about it.
>>>> Google search: brake hose internal collapse
>>>
>>> i see a lot of people bleating about it, but i've never seen anyone
>>> credibly explain how they think this "ghost in the machine", the thing
>>> they've never seen, is supposed to occur. if you think it's real, have
>>> you seen it? how do you think it's supposed to occur?
>>>
>>> my other favorite is this broadly accepted but erroneous superstition
>>> that pumping the brake pedal when bleeding fluid causes master cylinder
>>> seals to fail - totally ignorant of the fact that the fresh brake fluid
>>> they're using causes their previously over-swollen seals to shrink.
>>> i.o.w, rather than learn about the nature of seal materials, brake
>>> fluids, and how the two interact, they "believe" in the ghost of
>>> something they've never seen, never tested, and can't explain
>>> mechanistically.
>>
>> I've personally seen it happen, and know how it happens. It's because
>> the lip of the seal is dragging over a typically unused section of the
>> bore, and if the fluid hasn't been changed in a decade or more,
>> there's corrosion there, which is abrasive.
>>
>> nate
>
> I agree with you on this one Nate. I have personally ruined several
> m/c's this way.

you think you have, but you haven't. read my post again. you've
experience seal shrinkage due to the introduction of fresh fluid.

--
nomina rutrum rutrum

On 12/19/2010 01:56 PM, jim wrote:
> jim beam wrote:
>
>>
>> i see a lot of people bleating about it, but i've never seen anyone
>> credibly explain how they think this "ghost in the machine", the thing
>> they've never seen, is supposed to occur. if you think it's real, have
>> you seen it? how do you think it's supposed to occur?
>
> The flexible hose is composed of layers. If there is a tear in the
> inner rubber lining which creates a flap and that may behave as a
> one-way valve (i. e. check valve).

how does this "flap" form jim? and how does it manage to orientate
itself to form a one-way valve in this direction and not some other?
bearing in mind of course that this "flap" will need to have a length
greater than the bore of the tube, /and/ get folded over within that
bore, even though it's too long to fit. [also bearing in mind that
there is no fluid flow to assist - brake fluid only "flows" when being
bled. the rest of the time, it's merely a static pressure transfer medium.]

and most of all, if the inner tube is somehow "torn", why does the hose
not then burst? because if the inner is torn, then there's no fiber
bracing for the outer, and it'll just burst right through.


> If the brakes are not releasing and
> cracking loose the hose connection away from the caliper does not
> release the brakes but cracking the connection on the caliper end of
> the hose does release the brakes that is pretty good evidence that the
> hose is at fault.

hoses crack and burst, or their connections burst. there is no other
"natural" failure mechanism.


>
>
>
>>
>> my other favorite is this broadly accepted but erroneous superstition
>> that pumping the brake pedal when bleeding fluid causes master cylinder
>> seals to fail - totally ignorant of the fact that the fresh brake fluid
>> they're using causes their previously over-swollen seals to shrink.
>> i.o.w, rather than learn about the nature of seal materials, brake
>> fluids, and how the two interact, they "believe" in the ghost of
>> something they've never seen, never tested, and can't explain
>> mechanistically.
>
> New brake fluid causes seals to shrink smaller than when they are new?
> Nice fantasy.

nope, look it up. among other places, you can read about it he
isbn 978-0-8376-1540-0.

besides, they're not shrinking smaller than new, they're shrinking
smaller than their "expanded but worn" size. that's a very important
distinction.


>
> The only damage to MC's that has failed due to the travel going too
> far that I have seen had torn seals and it was easy to see what down
> deep in the bore tore the seal. If you are going to pump the brakes
> there is no reason to do full strokes. Just grab hold of pedal and
> back and forth an inch or so is just as effective in building up
> pressure.

to not use full bore is very unsafe.

1. if you have to emergency brake, you will need to apply the brakes
much harder than normal. the cylinder and the seals MUST be able to
withstand this application.

2. if one of the circuits fails [burst hose - see above], again, the
pistons MUST be able to safely use the full length of the bore.

/if/ there is any problem, say corrosion where fluid has not been
changed for a very extended period or the fluid has become contaminated
by oil, then the seals will indeed get torn, but that is a problem you
want to know about in the shop, not on the road, so yet again, ALWAYS
bleed by pumping full bore.


>
>
> -jim
>
>
>
>>
>>>
>>>> before you do that though, press the brake pedal with your hand. if
>>>> the free play has been adjusted out, you've found your problem.
>>>>
>>>>
>>>>>>
>>>>>>> Bad master cylinder, won't release pressure.
>>>>>>> Don't know if it has abs, but that is another possibility.
>>>>>>>
>>>>>>
>>>>>>
>>>>
>>>>
>>
>> --
>> nomina rutrum rutrum


--
nomina rutrum rutrum

On 12/19/2010 12:54 PM, Nate Nagel wrote:
> On 12/19/2010 03:37 PM, jim beam wrote:
>> On 12/19/2010 12:33 PM, Nate Nagel wrote:
>>> On 12/19/2010 01:15 PM, jim beam wrote:
>>>> On 12/19/2010 12:50 AM, Paul in Houston TX wrote:
>>>>> jim beam wrote:
>>>>>> On 12/18/2010 05:49 PM, Paul in Houston TX wrote:
>>>>>>> Programbo wrote:
>>>>>>>> Hello all. OK just to keep it short, my brother has a 1994 Dodge
>>>>>>>> Caravan with the 3.0 engine and automatic transmission. This may or
>>>>>>>> may not be relevant to what I am about to ask but at the
>>>>>>>> beginning of
>>>>>>>> last week he had the rack and pinion changed. Now he says when he
>>>>>>>> drives after about 20-30 minutes of city driving the brakes
>>>>>>>> begin to
>>>>>>>> drag badly so that the van is hard to drive. He said last night it
>>>>>>>> was
>>>>>>>> so bad when he got home he saw both front calipers "glowing red". I
>>>>>>>> just had time now to pull of the front wheels and had him pump the
>>>>>>>> brakes and hold the pedal down and opened the bleeders and both
>>>>>>>> had a
>>>>>>>> strong fluid pressure so I know the master cylinder is working
>>>>>>>> fine in
>>>>>>>> that regard. My question is..Is it possible BOTH front calipers are
>>>>>>>> going bad at the exact same time and if that's unlike what else
>>>>>>>> could
>>>>>>>> I look at as the cause? Thanks in advance
>>>>>>>
>>>>>>> Two bad calipers are possible.
>>>>>>> Bad hoses that are frayed inside.
>>>>>>
>>>>>> how is that going to happen?
>>>>>
>>>>> 1. I was thinking that maybe they were almost freezing up already
>>>>> but not noticed.
>>>>
>>>> maybe, but if the symptoms are as bad as you say, you should have
>>>> noticed before the rack was changed.
>>>>
>>>>
>>>>> 2. Something the shop did to the calipers or bushings.
>>>>
>>>> swap in crappy ones? that's not probable.
>>>>
>>>>
>>>>> 3. Shop stretching the hose and rupturing them internally
>>>>> during the r&p replacement.
>>>>
>>>> why do people so susceptible to this "ghost in the machine" argument?
>>>> hoses are hollow rubber cylinders. any rupture goes external and you
>>>> lose brake fluid. there's no internal componentry that can cause this
>>>> effect. the only possibility is a twist in the hose causing a pinch.
>>>> and
>>>> that will be obvious if you take the wheels off and look.
>>>
>>> not so. if a shop clamps off brake hoses with vice-grips etc. it's
>>> entirely possible that they may be damaged internally but that that
>>> damage isn't visible externally.
>>>
>>> nate
>>>
>>
>> have you ever seen this? have you ever tested for it? and what do you
>> think is the mechanism for its occurrence?
>>
>
> yes. yes. a flap of material coming loose around the area that was clamped.

1. how does it form correctly oriented?

2. how does it form to be the correct length longer than the bore of the
tube?

3. how does it manage to fold onto itself given that it has to be longer
than the bore of the tube?

external clamping pressure can achieve none of these things - #3
particularly. there's no "flow" in the tube that can magically assist
in this function either.




>
> nate
>
>


--
nomina rutrum rutrum

On 12/19/2010 12:59 PM, cavedweller wrote:
> On Dec 19, 3:37�pm, jim > wrote:
>> On 12/19/2010 12:33 PM, Nate Nagel wrote:
>>
>>
>>
>>> On 12/19/2010 01:15 PM, jim beam wrote:
>>>> On 12/19/2010 12:50 AM, Paul in Houston TX wrote:
>>>>> jim beam wrote:
>>>>>> On 12/18/2010 05:49 PM, Paul in Houston TX wrote:
>>>>>>> Programbo wrote:
>>>>>>>> Hello all. OK just to keep it short, my brother has a 1994 Dodge
>>>>>>>> Caravan with the 3.0 engine and automatic transmission. This may or
>>>>>>>> may not be relevant to what I am about to ask but at the beginning of
>>>>>>>> last week he had the rack and pinion changed. Now he says when he
>>>>>>>> drives after about 20-30 minutes of city driving the brakes begin to
>>>>>>>> drag badly so that the van is hard to drive. He said last night it
>>>>>>>> was
>>>>>>>> so bad when he got home he saw both front calipers "glowing red". I
>>>>>>>> just had time now to pull of the front wheels and had him pump the
>>>>>>>> brakes and hold the pedal down and opened the bleeders and both had a
>>>>>>>> strong fluid pressure so I know the master cylinder is working
>>>>>>>> fine in
>>>>>>>> that regard. My question is..Is it possible BOTH front calipers are
>>>>>>>> going bad at the exact same time and if that's unlike what else could
>>>>>>>> I look at as the cause? Thanks in advance
>>
>>>>>>> Two bad calipers are possible.
>>>>>>> Bad hoses that are frayed inside.
>>
>>>>>> how is that going to happen?
>>
>>>>> 1. I was thinking that maybe they were almost freezing up already
>>>>> but not noticed.
>>
>>>> maybe, but if the symptoms are as bad as you say, you should have
>>>> noticed before the rack was changed.
>>
>>>>> 2. Something the shop did to the calipers or bushings.
>>
>>>> swap in crappy ones? that's not probable.
>>
>>>>> 3. Shop stretching the hose and rupturing them internally
>>>>> during the r&p replacement.
>>
>>>> why do people so susceptible to this "ghost in the machine" argument?
>>>> hoses are hollow rubber cylinders. any rupture goes external and you
>>>> lose brake fluid. there's no internal componentry that can cause this
>>>> effect. the only possibility is a twist in the hose causing a pinch. and
>>>> that will be obvious if you take the wheels off and look.
>>
>>> not so. if a shop clamps off brake hoses with vice-grips etc. it's
>>> entirely possible that they may be damaged internally but that that
>>> damage isn't visible externally.
>>
>>> nate
>>
>> have you ever seen this? �have you ever tested for it? �and what do you
>> think is the mechanism for its occurrence?
>
> There's a "whip" test for brake hoses. (SAE probably

"probably"?

and any "whip" would be for kinking.


> has it covered)
> Entirely possible for one of the braid layers to degrade and project
> into the internal passage at the completion of the test.

if it does, the hose will burst from inside to outside, not outside to
inside. the latter is the only way you could possibly get a "flap".
and that can't happen from clamping since the pressure from the two
opposing walls prevents both contacting parts from doing so.


>


--
nomina rutrum rutrum

jim beam wrote:
> On 12/19/2010 01:39 PM, Paul in Houston TX wrote:
>> Nate Nagel wrote:
>>> On 12/19/2010 03:35 PM, jim beam wrote:
>>>> On 12/19/2010 11:21 AM, Paul in Houston TX wrote:
>>>>> jim beam wrote:
>>>>>> On 12/19/2010 12:50 AM, Paul in Houston TX wrote:
>>>>>>> jim beam wrote:
>>>>>>>> On 12/18/2010 05:49 PM, Paul in Houston TX wrote:
>>>>>>>>> Programbo wrote:

>>>
>>> I've personally seen it happen, and know how it happens. It's because
>>> the lip of the seal is dragging over a typically unused section of the
>>> bore, and if the fluid hasn't been changed in a decade or more,
>>> there's corrosion there, which is abrasive.
>>>
>>> nate
>>
>> I agree with you on this one Nate. I have personally ruined several
>> m/c's this way.
>
> you think you have, but you haven't. read my post again. you've
> experience seal shrinkage due to the introduction of fresh fluid.
>
Interesting. What could be the mechanism?

On Dec 20, 1:48*am, jim beam > wrote:
> On 12/19/2010 12:59 PM, cavedweller wrote:
>
>
>
> > On Dec 19, 3:37 pm, jim > *wrote:
> >> On 12/19/2010 12:33 PM, Nate Nagel wrote:
>
> >>> On 12/19/2010 01:15 PM, jim beam wrote:
> >>>> On 12/19/2010 12:50 AM, Paul in Houston TX wrote:
> >>>>> jim beam wrote:
> >>>>>> On 12/18/2010 05:49 PM, Paul in Houston TX wrote:
> >>>>>>> Programbo wrote:
> >>>>>>>> Hello all. OK just to keep it short, my brother has a 1994 Dodge
> >>>>>>>> Caravan with the 3.0 engine and automatic transmission. This may or
> >>>>>>>> may not be relevant to what I am about to ask but at the beginning of
> >>>>>>>> last week he had the rack and pinion changed. Now he says when he
> >>>>>>>> drives after about 20-30 minutes of city driving the brakes begin to
> >>>>>>>> drag badly so that the van is hard to drive. He said last night it
> >>>>>>>> was
> >>>>>>>> so bad when he got home he saw both front calipers "glowing red".. I
> >>>>>>>> just had time now to pull of the front wheels and had him pump the
> >>>>>>>> brakes and hold the pedal down and opened the bleeders and both had a
> >>>>>>>> strong fluid pressure so I know the master cylinder is working
> >>>>>>>> fine in
> >>>>>>>> that regard. My question is..Is it possible BOTH front calipers are
> >>>>>>>> going bad at the exact same time and if that's unlike what else could
> >>>>>>>> I look at as the cause? Thanks in advance
>
> >>>>>>> Two bad calipers are possible.
> >>>>>>> Bad hoses that are frayed inside.
>
> >>>>>> how is that going to happen?
>
> >>>>> 1. I was thinking that maybe they were almost freezing up already
> >>>>> but not noticed.
>
> >>>> maybe, but if the symptoms are as bad as you say, you should have
> >>>> noticed before the rack was changed.
>
> >>>>> 2. Something the shop did to the calipers or bushings.
>
> >>>> swap in crappy ones? that's not probable.
>
> >>>>> 3. Shop stretching the hose and rupturing them internally
> >>>>> during the r&p replacement.
>
> >>>> why do people so susceptible to this "ghost in the machine" argument?
> >>>> hoses are hollow rubber cylinders. any rupture goes external and you
> >>>> lose brake fluid. there's no internal componentry that can cause this
> >>>> effect. the only possibility is a twist in the hose causing a pinch. and
> >>>> that will be obvious if you take the wheels off and look.
>
> >>> not so. if a shop clamps off brake hoses with vice-grips etc. it's
> >>> entirely possible that they may be damaged internally but that that
> >>> damage isn't visible externally.
>
> >>> nate
>
> >> have you ever seen this? have you ever tested for it? and what do you
> >> think is the mechanism for its occurrence?
>
> > There's a "whip" test for brake hoses. *(SAE probably
>
> "probably"?
>
> and any "whip" would be for kinking.
>
> > has it covered)
> > Entirely possible for one of the braid layers to degrade and project
> > into the internal passage at the completion of the test.
>
> if it does, the hose will burst from inside to outside, not outside to
> inside. *the latter is the only way you could possibly get a "flap".
> and that can't happen from clamping since the pressure from the two
> opposing walls prevents both contacting parts from doing so.
>
>
>
> --
> nomina rutrum rutrum



Whatever you say, dude.

aarcuda69062 > wrote in news:nonelson-
:

> In article >,
> Tegger > wrote:
>

>>
>> Did the garage need to remove the master cylinder to replace the rack?
>
> It's not part of the procedure. Everything is done under the vehicle
> except disconnecting the outer tie rod ends.



Wasn't sure, but I thought it was a fair question considering the
coincidentally-sudden onset of the problem.


--
Tegger