[Bruckner]

A few weeks ago I replaced the front rotors and pads with OE pads and Zimmermans rotors, and performed the bed in procedure (5-6 moderate stops from 50 to 5mph). Shortly after install, I started getting loud squealing on very light brake application when coming to a stop.

 

I went on to cleaning the rotors with brake cleaner, to no avail.

 

When the squeal presents itself, I modulate the brake pedal to increase or decrease pressure, to try to kill the squeal, with about 50-50 success rate. But, if the squeal is allowed to continue until full stop, the resonance gets so bad that the speedometer will momentarily jump to 40mph and back within a second. I'm thinking the vibration through a caliper is so bad that the speed (ABS?) sensor is thrown off. Just a theory.

 

After a loud squeal on braking, I usually get an odd resonance through the steering wheel when accelerating again.

 

All of this is very strange to me. Any ideas?

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[Rap]

Assuming everything was installed correctly, have you tried different pads? The cobalt racing pads I used squealed but with no resonance thru the steering wheel. 

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[vliegwielolaf1234]

Did you install new brakepad vibration dampers ? 

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[tejon007]

Just a couple months ago I had a squeal from ceramic pads I installed on a Prius (used new rotors too). Final resolution was new pads from another manufacturer.


Here is the bed-in procedure I've used to good success over the years:


https://m.pmbperformance.com/bedin.html

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[Bruckner]

Did you install new brakepad vibration dampers ? 

 

No I did not, most likely problem. I'm thinking new OE Porsche pads should not be at fault here. I will start by taking the pads out, clean thoroughly the caliper and see what's in there. Truth be told, I never paid attention to vibration dampers, and only found out recently that the WSM states they must be changed every time pads are replaced.

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[J.Elenbaas]

I replaced my rotors and pads last year, also bought the vibration dampers with it (anti squeal pads).

However the Porsche pads i bought wouldn't fit together with the extra dampers.

 

On the brakepads there already is something attached that does the same job.

 

So i think it will be easy to see for you when you take the pads out, if the backside (steel part) has something extra attached to it you won't need the extra dampers.

If you only see the steel backplate you will need the dampers

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[Bruckner]

I replaced my rotors and pads last year, also bought the vibration dampers with it (anti squeal pads).

However the Porsche pads i bought wouldn't fit together with the extra dampers.

 

On the brakepads there already is something attached that does the same job.

 

So i think it will be easy to see for you when you take the pads out, if the backside (steel part) has something extra attached to it you won't need the extra dampers.

If you only see the steel backplate you will need the dampers

 

Thanks. Can you detail what exactly I should be looking for? There surely is a steel plate with the part number stamped on the backside, but not sure what this "something else" I'm looking for?

 

I had a look in there on the driver side and there were no dampers in any of the pistons. I did have a look at the old pads that I kept and found residue of anti squeal paste where the pistons contact the pads, but nothing attached to the backside plate.

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[Waylander]

Most modern pads now come with a anti squeal pad on the back of the pad, 

 

this normally looks like a raised section on the rear of the pad, about .5-1.0 mm thick, covering almost all of the back of the pad, if the pads have this then you try to add the Porsche dampers the pads become to thick to fit in the caliper

 

I have never use the Porsche dampers, I have no noise from the brakes, the genuine dampers will set you back quite a bit of money

 

the 36mm ones are $6.50 each x 4, 964.351.096.01

the 40mm ones are $7.00 each x 4, 964.351.096.02

 

the rear ones are twice as expensive for some strange reason

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[vliegwielolaf1234]

I always reuse them ,remove ,clean ,ad thin dubbel sided tape ,  reinstall , never had any problems .

I only have used oem brand pads .

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[J.Elenbaas]

 

Thanks. Can you detail what exactly I should be looking for? There surely is a steel plate with the part number stamped on the backside, but not sure what this "something else" I'm looking for?

 

I had a look in there on the driver side and there were no dampers in any of the pistons. I did have a look at the old pads that I kept and found residue of anti squeal paste where the pistons contact the pads, but nothing attached to the backside plate.

 

Read Waylanders explanation!!

But as i see in your question above you only found the steel plate with number stamped on the back on the brakepad, so no damping on it.

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[Bruckner]

Thanks. OE dampers are needed to use OE pads. The 951 and 968 owners I spoke to all run aftermarket modern pads, most of which come with anti squeal shims, hence why they consider OE dampers superfluous.

 

Leaning every day!

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[MCL968]

I always reuse them ,remove ,clean ,ad thin dubbel sided tape ,  reinstall , never had any problems .

I only have used oem brand pads .

Same here, I pulled out the original dampeners and just removed the dampening material since the pads already had it in their backing plates. Once the dampening material was removed, the adhesive remained, which made them adhere perfectly to the new pads. Two years and lots of miles later, still no squeaks.

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[Bruckner]

Well the mystery remains unsolved. I installed the porsche dampers, all 8 of them, and while the squealing is noticeably dampened, I now get a grinding noise at low speeds when lightly applying brakes, the sort of grind you get for a second or two when driving a car that's sat in damp weather for a few days with rusty rotors.


Brakes still feel strong and smooth at higher speeds, but city driving is very unpleasant.


I consulted with 2 mechanics who couldn't see anything wrong with the brakes, with visual inspection (wheels and pads off).


The car has 160,000 miles, could one of the calipers have a sticky piston when warmed up? I'm out of ideas so any help appreciated.

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[MCL968]

I had a similar problem years ago. One of the pads was not manufactured quite right and the pad material was touching the unmachined (rough) part of the rotor. New pads solved the problem.

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