S-Type R Brembo Brakes Squeal

Congratulations, You have learned lesson number 1 about Jag dealers -- they don't know what they are talking about.

I am not particularly familiar with the S-Type, but I am familiar with Jags and brakes and Brembos. I have 3 Jags and two of them run Brembo rotors and pads. I also have a friend with a 2001 XJR with the Brembo brake system and it does not squeal. Squealing of brakes is caused by a vibration of the pad against the rotor. It is a common occurrence.

Quality brake pads come with thin metal plates that are called shims that go between the pad and the piston in the caliper. In most cases, a sealant is used between the surface of the shim and the pad itself to absorb the vibration and eliminate the noise. Most after market auto parts stores carry this sealant. In my own particular case, I simply use silicone sealant like you would use it seal a bathroom sink -- but with higher heat properties. This eliminates the vibration to the point the squealing goes away.

When the service guy at the Jag dealership sprayed on the compound, he was simply doing it to make you go away. As you are aware, as soon as the compound dried and wore off -- the sequel returned. Squealing has been a common problem with common solutions for 40+ years -- since the widespread use of disk brakes. Most cars have disk brakes. Stand in a parking lot and listen to see how many cars squeal as they brake.

At some point, there must have been work done to the front brakes of your S-Type. Apparently, who ever did this work, forgot to replace the shims or forgot to use the anti-squeal compound on the shims/pads. If you have NOT had work done on the front brakes of this car, then the chances are -- you need to. Squealing is sometimes a method of letting the driver know the pads are getting low.

Now you know why I have 3 Jaguars and not one of them has ever darkened the service bay of the local dealership.

Webserve

You fail to mention that it is possible that *nothing* will absolutely and permanently eradicate squealing from disk brakes. It is an inherent property and, the better (higher performance) the brakes are, the *more likely it is* that they will squeal. Even doing *all* of the recommended things is no guarantee your brakes won't continue to squeal. This is not necessarily a sign of incompetence but of a lack of technology available to ensure the result. *If* there were a sure fix, all the high-end manufacturers would have been using it by now.

That said, for the lowest-cost fix, one can nearly always minimize the noise by modulating braking pressure. Either brake harder and more aggressively or softer and more gently because the noise is a product of not only the surfaces involved (affected by gunks and shims applied to the parts) but also of the clamping pressure and speed of the surfaces.

-- C.R. Krieger (Been there; done that)

Well reasoned but I don't think I agree. Have had a number of high performance vehicles, Jags, Jensens, Aston-Martins but have never had a brake squeal. Surely it's not inherent in the actual technology unless there's a fault?

Although disk brakes are all prone to developing squeal, individual driving habits can avoid squealing brakes. You are apparently one of the lucky ones. Frequently modulating your braking both firmly and softly can completely eliminate squeal in some cases. One very important factor is pad composition. Many high-end manufacturers will tend to use a softer pad for their street cars to help eliminate squeal. They also tend to use more part- and labor-intensive measures such as antisqueal shims and antisqueal 'gunks'. Therefore, the noise occurs less often.

-- C.R. Krieger (Been there; done that)