New Zimmerman rotors and pads squeal

Hello, I recently had all four rotors and pads replaced with Zimmerman products. The car is a 996.1 C2 6-spd year 2001 Besides the rotors and pads I also got new anti-vibration shims which were lubricated with Brembo b-quiet before going into the pistons. Bedding process was done as per the instructions. The new rotors and pads have now done about 2000km. At approximately 400km I started to notice a high pitched noise when gently stopping at low speed, from approximately 30km/h to 0km/h. A short squeak can also be heard when stopping at medium speed from about 90km/h to 80km/h. When I do a couple hard braking manoeuvres from about 100 km/h to 30km/h (without ABS interference) the brake noise seems to stop for about 20km. Then it gradually appears again until I have a lot of noise. Does anyone have experience with Zimmerman rotors/pads on these cars and has anyone had similar issues with noise? How did you solve them? Thank you for your help.

I'm going to say that you will never fix that. It is a product of the friction material. Sounds like a higher temperature compound. Works great when hot, but when cold (i.e. not at higher brake temps during aggressive braking), the compromise is squeal. BTDT on cars in the past, you can take everything apart as many times as you want and lube everything up, but they will still squeal at low brake pressures. The easiest way to solve this is to get some new pads. I like the AKEBONO EUR776 (front) and EUR738 (back), both for a 996.1. I have used these pads on so many cars that I have fixed and owned, they basically do not dust and perform like OEM pads. I have yet to put them on my 996 as I have never changed the brake pads during my ownership. They are at the bottom of the page here: https://www.rockauto.com/en/catalog/...brake+pad,1684 Or consider Pagid pads. Best of luck.

Try to rebed them do some very high speed stops SAFELY it’s worked for me in the past

It's not the rotors, it's the pads. The anti-squeal shims will help, but the pads are the problem. As NYPOWR4 said, try rebedding them. If all else fails, different pads would be the next choice. I run Hawks for the street and they are totally quiet and virtually dust free.

Thank you for your help. I was already leaning towards changing the brake pads. Besides the noise, the original Zimmermann ones produce a fair bit of dust so I am keen to try the ceramic compounds. Maybe I will go for Brembo ceramic pads since there doesn't seem to be a dealer for AKEBONO in Europe. Regarding the re-bedding, I already tried that a few times since the Zimmermann FAQ page suggests that a layer of something gets formed on the brake pads/rotors and can cause the squealing. Sadly it didn't work in my case, the squealing was back after a few dozen km. Will report back with results in a few months...

The brembo ceramic suck order the akebono from outside and get them they are fantastic

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You said you put in new shims, but are you really talking about the dampeners? That�s what solved my squealing after a lot of frustration and experimentation.

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The only time I didn't do dealer service on my old Audi Q5 I had a highly-rated German independent do the brakes. He used Zimmerman rotors and pads, and they would squeal like crazy. I brought it back to the shop a few times, and he removed and cleaned and lubed and whatevered them, but they would start squealing again. I eventually gave up and lived with it. I haven't had to replace 996 pads yet, but I suspect that @Paul Waterloo is correct that this won't go away -- at least based upon my Q5 experience.

Before spending any money...Most pad noise is related to the pads and discs not being bed-in properly. Please see the video below: You Tube

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He had bedded them in the way Zimmermann described, I read in his post... That the squealing is gone for a certain amount of time or number of brake actuations is testament to this procedure as a layer of pad material is deposited onto the disk, the brake force is now between pad and deposited pad material whereby no squeal is caused. Now here comes the explanation for what OP is experiencing: subsequent braking is too timid (but harder braking is just not practical) for this layer to be maintained. Instead the contrary happens: each subsequent braking actually removes a bit from the deposited pad material until it's all gone and the braking force is again between pad material and cast iron brake disk surface, resulting in brake squeal in this disk and pad combo as well as use. My advice is to change to another brand of pads. Personally I'd stay away from ceramic pads as I don't mind the dust but I do appreciate good initial bite and wider operating temperature range that organic pads offer over ceramic pads. Ate and Textar are good pad manufacturers to name. As these are standard pads for use on public roads they'll be squeal-free in such an environment. Do the Zimmermann pads have these 2 little metal cilinders attached to each pad? Those weights are on stock pads to reduce/eliminate brake squeal

I have Zimmermann rotors with Textar pads (and with those dampeners that are on barbancourts message). Didn't notice any squealing last summer/autumn but my driving was somewhat limited due to that BS scenario.

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Yes, I meant these. The ones in the picture are for the front, the back calipers get four circular ones for each caliper. Sadly they didn�t solve the problem. Properly installed and everything. Thank you all for the suggestions. Surprisingly it�s difficult to get any kind of �street� ceramic pads in Europe. Brembo actually don�t supply those ceramic ones to European dealers. It seems that I will go with the Akebono as suggested by the majority and import them. Will report back on the results�

Could be that those Akebono pads are not homologated in Europe for public road use (no E marking on them that would signify ECE R90 is met) and therefore illegal for such use. Depending on where you live and drive in Europe the consequences of that in case of an accident can be dire. Just something to be aware of.

Wow fing big brother is annoying even in Europe

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Having lived in Germany for many years, they are much much worse than the USA. Those T�V inspections are no joke. They fail you for anything.

I did a full brake job not long ago and chose Zimmerman rotors and Akebono pads. Zero squeal. Paul and others are right, it�s the pads. It�s almost always the pads. BTW, my mechanic told me he has done hundreds of brake jobs and never performed a brake bed procedure.

I've read somewhere that ceramic pads have less stopping power when cold. I sometimes drive my car at low temperature, just above or around freezing, and wonder what is your experience?

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I had squeal on Brembo rotors and pads, then also had squeal on Zimmermann rotors and Pagid pads. Only thing that fixed my squeal was installing the dampeners that the PO had not installed. Could be that the Akebonos don�t squeal with or without dampeners. Not ruling that out as a possibility.

Ahh, good point. I did the dampers on my car as well. I agree, when it doubt, do the dampers. They aren�t cheap either.

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I recall them being relatively cheap. Roughly $50 for the entire front end. I think that�s where most people get the squealing. Maybe it is expensive but I�m just desensitized to $50 costs after owning a couple 911s. Seems like every repair is $200 minimum.

My brake parts ended up costing me $1200. I buy from PelicanParts, not the cheapest, but I love their quality and advice, tech articles, etc. Yeah, $50 doesn�t sound bad, but it�s $100 for all 4 corners for just a couple pieces of rubber.

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Cold and hot in brake context refers to the temperature of the disks and pads, not the ambient air. The 20 degrees difference in ambient temperature is negligible wrt brake performance. However, ceramic , low-dust pads have a lower coefficient of friction and need a higher brake pressure to deliver the same brake performance as standard pads and that is true for cold and warm brakes. Brake feel is affected too, those low-dust pads just donot offer the same initial bite as standard pads do.

I previously had new ATE and Brembo front discs and pads on this car which did not squeal. The reason I had to change them so fast was because the workshops wrongly diagnosed a shaking under braking issue to warped rotors but in fact it was the wheel hub that was slightly bent since I had purchased the car. That was fixed and solved and all four corners got new Zimmermann rotors and pads which are great with the exception of the squealing. Anyway... Due to several question marks about the ceramic pads (low temperature bite and certification) I am now considering the change to Brembo HP2's which are R90 certified and marketed as an upgrade to the standard Brembo pads. They are also marketed as "silent operation" so I am hopeful.

I know you're not asking but with having a squeal issue I would go for a standard brake pad instead of 'uprated'. The former put much more emphasis on squeal-free operation, the latter less so and instead focuses on keeping the coefficient of friction up to a higher disk/pad temperature, that you won't achieve (as often as braking from 50km/h to standstill) even on an unrestricted stretch of German autobahn, when someone on the middle lane decides to enter the left lane at 130km/h and forces you to brake hard.

My brembo�s squeeled. Replaced pads and good to go, no special procedure done.

Hello, I just wanted to give an update on this for anyone who might encounter the problem at a later date. To recap: the OEM Zimmermann rotors and pads for my 996.1 C2 were squeaking and giving an annoying high pitched sound at low speed stopping. I replaced the front and rear pads with standard Brembo OEM's (P65009 and P65008) and after bedding and driving for about 500 miles the noise is gone.