Mechanics

NOISE WHILE HITTING THE BRAKE WHEN NEAR A STOP.

2004 Volkswagen Passat • 92,000 miles

Hi, guys,

I just got another problem after I installed the new upper control arms and CV axles for both sides. I just made a video in order to describe this symptom more clearly. the mechanic told me that is because of the brake pad are new. However, this never happened before I installed the new parts on it.( I already have the brake pad for a while). please help me figure this out.....I will be so appreciated.

this happened only when I "ALMOST STOP" and pressing the brake.my foot can feel something when put it on the brake pedal, its like I'm against something..

the only thing they did to my car is..I think we did the tire rotation, new cv axles, new upper control arms (bushings). I think thats all. I am just afraid that I am destroying something which I don't know.......if I leave the problem there.

please see the video and hear the noise. the noise comes when I hit the brake

http://www.youtube.com/watch?v=lHXo_t1tiog
Avatar
Changchingchi
October 7, 2012.



Do you feel vibration in the brake pedal? If yes, the it is you abs that is kicking in at lower speeds.

Check the front abs speeds sensors to see if they are sitting all the way in place. An air gap
that is bigger for one sensor than the other will cause different speed readings by the abs
module and activate the abs.

Thomas


Tiny
Exovcds
Oct 7, 2012.
Stupid spell check. "Then it is your abs that is kicking in".

I just re-read your post. You are feeling something in the pedal, so I would for sure check the front
abs sensor positions.

Thomas


Tiny
Exovcds
Oct 7, 2012.
If the gaps are OK. Check the teeth of the outer cv joints. Chipped, broken or cracked teeth will
cause signal issues that can cause abs activation.

Thomas


Tiny
Exovcds
Oct 7, 2012.
Also check for rust as that can cause noise problems.


Hmac300
Oct 7, 2012.
Can it be the problem from caliper?


Tiny
Changchingchi
Oct 8, 2012.
Not if what you feel in the pedal is a rapid pulse.

The noise I am hearing is the ABS pump & valves clicking. But I can't
be 100% sure unless I feel & hear it in person.

The fact that all this started AFTER you had the CV / drive shafts
replaced, leads me to think that there is an ABS issue (sensor or
tone wheel on the outer cv joint).

A loose caliper bolt can cause a 1 time knock during brake application
that can be repeated less rapidly.

Thomas


Tiny
Exovcds
Oct 8, 2012.
I will just ask them to check from what you said. From ABS pump & valves, the front abs sensor, to the teeth of the outer cv joints. Will updated it.


Tiny
Changchingchi
Oct 8, 2012.
Some reading before you take it in....

http://www.picoauto.com/tutorials/diagnosing-abs.html

Thomas


Tiny
Exovcds
Oct 8, 2012.
Hi, Thomas.

They are doing the reface the rear rotor and checking the abs sensor this time. But, something suddenly come to my mind, do you think it is possible because of wrong size of the CV axles? ( Can install but have space?) Furthermore, if it is because of the abs sensor, you think that can be better if we reboot the system?( Disconnect the battery?)
thanks for your helps. : )


Tiny
Changchingchi
Oct 8, 2012.
Depending on make / manufacturer of the shafts and as long as the
shop ordered the correct parts, I don't think that the "wrong"
shafts were installed. I would think that there would be a hard
fault at that point (ABS light ON & a stored fault code present in
the ABS Module) with an incorrect shaft installed.

Have them double check the parts to be sure.

A re-boot / disconnect probably won't fix anything.

On one of the other forums that I post on, someone changed his
cv shafts as well and had the same problem after. In his case
he noticed that one of the front sensors was not sitting all the
way in its seat. He lightly tapped it with a rubber hammer and
his low speed abs activation stopped.

Not sure why they are now focusing on your rear brakes. Like
you said, the problem was not present before the front cv shaft
change, so I would keep focus on the front.

Also, CV shafts can be changed without having to remove brake calipers
and pads. Ruling out any fault with those components.

Thomas


Tiny
Exovcds
Oct 8, 2012.
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