THEM'S THE BRAKES

  • Tiny
  • doublesharp
  • 2004 Mazda MPV
  • 128,000 miles

Our 2004 MPV Van recently began applying its own brakes. After being driven for about 5 minutes it would begin to need more and more gas pedal to maintain speed. It did not take long to realize that the car was braking since lifting the right foot caused rapid deceleration and then a complete stop. It can pass, or ease up, after a while, and return again, but it is not safe to drive like this and it will surely ruin the pads/rotors. When testing the car to see if it is working properly before taking off I will place it in Drive and let off the brake pedal. If it moves without applying the accelerator it is not grabbing. I will even test again by moving it to Neutral and watching the speed as indicated. If there is not a drop it is still moving freely. The brakes/calipers will close with no pressure on the pedal. As an example I have tried to drive it to a mechanic and while on the freeway done the Neutral test and then resumed driving (never touching the brake pedal) and the brakes apply by themselves. I have had the local Firest*ne dealer look at it three times and Mazda dealer twice. In order the responses were: FS) --- there is no problem. Mazda) --- there is no problem. Mazda) --- front caliper sticking. (Both calipers replaced) FS) --- I don't see a problem but maybe your rear pads are sooo worn that the piston/pistons are far enough out that the cylinder lip is catching and not allowing them to retract or bad/damaged hose. (New rear calipers and pads were installed) FS) --- It is the ABS pump. (ABS fuse pulled to remove ABS module from the equation) Problem continues. Firestone was used for three reasons; the problem occured nearest to them, they were open and they were aware of the problem. Have not taken the next step as I don't relish the thought of spending $1,200 plus labor on another guess. The only parts not replaced seem to be the ABS pump, brake booster and the master cylinder. Any insight would be greatly appreciated as in this situation my screen name does not apply (unlike my brakes). Respectfully I thank you

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Saturday, May 19th, 2012 AT 12:17 AM

8 Replies

  • Tiny
  • ASEMaster6371
  • Expert
  • 25,556 posts

Did anyone check the pushrod in the booster for adjustment

Roy

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Saturday, May 19th, 2012 AT 12:21 AM
  • Tiny
  • doublesharp
  • Member

They have been lost under my wife's van for so long they don't seem to really want to talk about what they have and haven't done.
I did get them to say that they believe it is the ABS pump b/c they couldn't get the fluid to move/bleed until they diconnected the pump.
I've got no experience beyond rebuild of calipers and replacing pads and such.

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Saturday, May 19th, 2012 AT 12:39 AM
  • Tiny
  • doublesharp
  • Member

Okay.2carpros obviously isn't enough. Good thing this is free.

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Sunday, May 27th, 2012 AT 11:41 PM
  • Tiny
  • CJ MEDEVAC
  • Expert
  • 9,359 posts

I'VE BEEN FOLLOWING ALONG

THE BOOSTER'S PUSH ROD WAS SOMETHING I WAS THINKING TOO

'CEPT I WAS GONNA ASK IF THE BOOSTER HAD EVER BEEN REPLACED, KINDA LEADING INTO CORRECT ADJUSTMENT OF THE ROD

THAT'S SOMETHING THAT GETS OVERLOOKED WHEN SOMEONE IS IN A HURRY, PLAIN IGNORANT, OR "MR CELLPHONE" HAS THEIR ATTENTION WHILE THEY SHOULD BE 100% COMMITTED TO THE TASK AT HAND

DO KEEP US UPDATED. WE LIKE TO HEAR THE REST OF THE STORY TOO

THE MEDIC

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Monday, May 28th, 2012 AT 4:22 AM
  • Tiny
  • doublesharp
  • Member

Saturday I was able to convince a shop to put on a new master cylinder and it seems to be working.
I say "Seems" only because we haven't been able to drive it more than 20 minutes or so yet.
Before it wouldn't go that far so we are hopeful.
Several folks mentioned the pushrod in either the master cylinder or the booster being out of adjustment but I couldn't/can't find anyone who even seems to about an ability to adjust the rod, let alone, how to do it.
I have even shown them a pdf file with step on how to do so at the master cylinder and they just don't get it.
I refuse to name my state of residence on the grounds that Jeff Foxworthy may choose to make a new bit about my plight.

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Monday, May 28th, 2012 AT 6:57 AM
  • Tiny
  • CJ MEDEVAC
  • Expert
  • 9,359 posts

MANY TIMES A NEW VACUUM BOOSTER (MAYBE EVEN A REMAN) WILL HAVE THE INSTRUCTIONS FOR PROPER ADJUSTMENTS

THIS MAKES THINGS EZ FOR YOU. NO MORE PULLING YOUR HAIR OUT!

SIMPLY GO TO THE AUTO PARTS STORE, HAVE 'EM THROW ONE UP ON THE COUNTER MADE FOR YOUR RIG AND SEE IF THEY WILL COPY THE INFO FOR YOU. PROBLEM SOLVED!

GLAD TO HEAR YOU ARE MAKING SOME HEADWAY

KEEP US INFORMED

THE MEDIC

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Monday, May 28th, 2012 AT 4:49 PM
  • Tiny
  • doublesharp
  • Member

Saturday replaced Master Cylinder.
Yesterday drove it for almost an hour and no problems.
Looking good.

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Tuesday, May 29th, 2012 AT 12:33 PM
  • Tiny
  • CJ MEDEVAC
  • Expert
  • 9,359 posts

GIVE IT A WEEK---THEN RETURN WITH A GRIN!

I HOPE YOU ARE GOOD TO GO!

FORGET OLE JEFF--WE WERE PRACTICING HIS ROUTINE DOWN HERE IN S.C. LONG BEFORE HE GOT THE RECOGNITION

THE MEDIC

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Wednesday, May 30th, 2012 AT 1:50 AM

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