Caravan: Both front calipers seized????

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

Reply to
Programbo
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Two bad calipers are possible. Bad hoses that are frayed inside. Bad master cylinder, won't release pressure. Don't know if it has abs, but that is another possibility.

Reply to
Paul in Houston TX

sounds like someone has adjusted the brake pedal free travel so the fluid pressure equalization circuit hole is blocked. probably happened while under the dash with the rack, they thought they'd "tighten things up". re-adjustment of the pedal travel back to standard spec should solve the problem.

Reply to
jim beam

how is that going to happen?

Reply to
jim beam

Programbo wrote in news:0a5ebb81-f345-43b4-a320- snipped-for-privacy@29g2000yqq.googlegroups.com:

Did the garage need to remove the master cylinder to replace the rack?

Reply to
Tegger

As a follow up..Is it possible the master cylinder is allowing fluid to freely pressure the pads into the rotors but not allowing it to flow back the other way and that eventually causes the problem I described?

Reply to
Programbo

It would have been more logical to check if the brakes were locking up or dragging. Have you checked for this? If you haven't, then you should.

Reply to
dsi1

kinda. but it's really the pressure equalizer valve being closed, so as the brake fluid warms up during use, it expands and starts to apply the brakes.

check out tegger's excellent write-up on master cylinder operation.

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i do not however agree with him on pedal adjustment just for replacing the master cylinder - the pedal should only be adjusted one time at factory, and then left alone. if there is wear, say the pedal bushing, the worn component needs to be replaced. there is NO adjustment required for replacing the master cylinder - new and old are dimensionally identical.

Reply to
jim beam

  1. I was thinking that maybe they were almost freezing up already but not noticed.
  2. Something the shop did to the calipers or bushings.
  3. Shop stretching the hose and rupturing them internally during the r&p replacement.
Reply to
Paul in Houston TX

Just thought of another thing: Vac Booster is not letting go due to: booster push rod out of adjustment bad atmospheric valve

Reply to
Paul in Houston TX

Programbo wrote in news:a7e4be99-51ad-495d-9273- snipped-for-privacy@g25g2000yqn.googlegroups.com:

Yes. That's why I asked the question I asked.

Reply to
Tegger

It's not part of the procedure. Everything is done under the vehicle except disconnecting the outer tie rod ends.

Reply to
aarcuda69062

After only 17 years?

Absolutely.

Reply to
aarcuda69062

As far as anyone reading your account knows, the rack and pinion was changed because stuck brake calipers were causing the whole front end to shudder. Some of the symptoms may have been alleviated but not the root cause.

-jim

Reply to
jim

maybe, but if the symptoms are as bad as you say, you should have noticed before the rack was changed.

swap in crappy ones? that's not probable.

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.

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.

Reply to
jim beam

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

Reply to
Nate Nagel

have you ever seen this? have you ever tested for it? and what do you think is the mechanism for its occurrence?

Reply to
jim beam

yes. yes. a flap of material coming loose around the area that was clamped.

nate

Reply to
Nate Nagel

There's a "whip" test for brake hoses. (SAE probably 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.

Reply to
cavedweller

  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.

Reply to
jim beam

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