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Discussion Starter #1
I have a 2011 Jetta and trying to figure out why my rear brakes after stopping for some time makes a shhhh noise when pressing the brakes. It's like a static radio sound and it comes from the rear. I changed the brake pads twice and the same result, the rotors look fine, and brake lines are stainless steel less than a year old. Any suggestions?

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Did you replace the shims, and or use Brake-Quiet on the back of the pads on the piston, and fingers of the Caliper for the Front pad?
Did you have the rotors turned? It sounds as if the pads are "chattering" The Brake-Quiet, tends to stop that...
And new pads on old rotors have to wear in to the grooves and ridges, and that may also be the noise that you are hearing, should ease up in a few hundred miles.
What it looks like and not where I buy it....
https://www.zoro.com/crc-high-temp-film-water-resistant-4-oz-5016/i/G3018057/?gclid=Cj0KCQjwtpDMBRC4ARIsADhz5O4Cp86-YMFUb8Slpbsmum21CF4UNnMm6z7kkz7MaTy65Pe-MEU4EkwaAkzBEALw_wcB&gclsrc=aw.ds

I use it every pad change.
 

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Discussion Starter #3
Did you replace the shims, and or use Brake-Quiet on the back of the pads on the piston, and fingers of the Caliper for the Front pad?
Did you have the rotors turned? It sounds as if the pads are "chattering" The Brake-Quiet, tends to stop that...
And new pads on old rotors have to wear in to the grooves and ridges, and that may also be the noise that you are hearing, should ease up in a few hundred miles.
What it looks like and not where I buy it....
https://www.zoro.com/crc-high-temp-film-water-resistant-4-oz-5016/i/G3018057/?gclid=Cj0KCQjwtpDMBRC4ARIsADhz5O4Cp86-YMFUb8Slpbsmum21CF4UNnMm6z7kkz7MaTy65Pe-MEU4EkwaAkzBEALw_wcB&gclsrc=aw.ds

I use it every pad change.
This has been happening even with the old pads. It was happening after everything was new, not old with new. I changed the pads 3 times and it still happens, brake quiet grease was used all times and shims were replaced each time.

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The stuff I linked isn't a Grease, it is a paste that hardens but remains flexible.
If it was happening with the old pads, then I would suspect a bad MC or issues with the ABS and Bleeding the system.
As when you let off the brakes the pistons should retract a wee bit, and it may be that you have issues with the ABS or MC that isn't allowing the piston to retract.
 

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Discussion Starter #5
The stuff I linked isn't a Grease, it is a paste that hardens but remains flexible.
If it was happening with the old pads, then I would suspect a bad MC or issues with the ABS and Bleeding the system.
As when you let off the brakes the pistons should retract a wee bit, and it may be that you have issues with the ABS or MC that isn't allowing the piston to retract.
I meant the paste but the word didn't come to mind. My fronts are fine with no noise, it's just the rear and the entire system was bled before they went in. The noise only happens when I press the brake pedal not depressing.
 

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Discussion Starter #6
Finished replacing the rotors while covered under warranty, lubed everything up with brake grease in the rears, inspected to make sure nothing was wrong. Guess what. The same dam noise. I guess it's time to look at the front now that I have all the tools to do the job myself.
 

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You always have drag with disc brakes, but you should not hear it. Are the pads
too close to the top of the rotor, or is the rotor dished? If the rotor is dished
you may be able to hear those edges drag on new pads. If they are NEW rotors
and NEW pads, well, that is odd indeed, unless the pad is slightly over the outer
edge of the rotor, or hitting the hub of the rotor...

I have changed pads on cars for over 30 years, and never heard brake pads
dragging. If the rotor has rust spots from sitting all weekend, I hear that for
a little while then it goes away.

Common brake noises and causes aren't even included in your description,
they go as far as scraping, but that means debris caught between the pad
and the rotor.

Pistons do not really retract when you let off the brake. Pressure is released,
then the pad wears till the drag is acceptable. Rear ones cannot retract
because the plunger twists as it comes out, and you need a tool to twist
it back in. This is how I see it, if wrong, oh well... I don't see them retract
at all.

BMW has has gone as far as to put two holes in the top of their pads, one at each end, and a metal
piece, like part of a coat hanger, spans across into the holes on both pads, so when you let up, the
metal thing pushes the pads apart as far as they will go. There is not enough push to effect the plungers.

Brake shims can cause more drag than not:
What was a eye opener for me was working on a friend's car. His front tires were nearly friction free
when turning, but mine were much tighter. Ends up he didn't have brake shims installed, but I did AND
I also had CRC brake silence compound. I ditched the shims, cleaned off the CRC goo, and now mine
too are nearly friction free.
Sorry, but I never use shims either... Of the pads come with shims, I don't install
them.

You can never eliminate drag with disc brakes, just make it as light as possible.
Many newer calipers do have any kind of return mechanisms.

The pads ride in metal channels in the caliper, and rust will also prevent
any kind of returning for the pad. One cure for this issue is to grind about
.020 inch from one end, or .010 off both ends of the supporting backplane
of the brake pad. I have SEEN shops do this to deal with the rust where
the pads slide in.

Also, The caliper will rust under the copper pad clips (if there), which also binds up the pads.
The pad clips may be smooth, the the rust under them pushes them out, and the pads don't
slide freely. Grinding will still work.

I put anti-seize on the pad backplane ends, back of the pad, and in the grooves. I clean
the grooves with a wire brush first... Oh, and as I said, no shims, no brake quiet anything...

Other than the rears being twist in, I can push the plungers in with my bare hands,
thumb on each side, and press, HARD. If I can't, then I decide I may need new calipers.
Sometimes it hurts, but I can push them in, if they're not the twist in type. I was amazed
at how easy my charger plungers pushed in, front and rear... The fronts on my Jettas
I was able to push them in myself. Had to buy the tool for the rears...
 
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