There's no other way to describe it. When the brakes get warmed up there is a groaning sound when they're applied. Could the previous owner have put in non OEM pads? I had a similar problem when replacing the front pads on my girlfriend's BMW 733i, when I changed them with non OEM pads there was a groaning sound. Is there a difference in density of these pads that can cause this? Must they be matched carefully with the brake system in question? Thanks in advance for your advice.
Thom

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1987 300E
1967 Jaguar E-type Series I, 2+2

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Regards,

Albert
aldedmon@yahoo.com

Thanks, but could you expand on this a little?

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1987 300E
1967 Jaguar E-type Series I, 2+2

The problem occurs when the wheels/axles/brakes etc are at operating temp. If you drive it home and immediately jack up the car on the offending side, and then rotate the hub(with or with the wheel) and inspect the area from whence cometh the noise, you should be able to tell precisely what is the matter. Could be a grinding wheel bearing or perhaps a worn pad grinding to the disc

__________________
Regards,

Albert
aldedmon@yahoo.com

My money is on a dry wheel bearing(s). As one poster suggested, pull both wheels and look at the pads and rotor surface. If these look ok, pull the bearings.

But if it were a front bearing wouldn't I hear a howling sound while at high speed? This only happens when the brakes are applied. Thanks.
Thom

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1987 300E
1967 Jaguar E-type Series I, 2+2

Brake noise is caused by vibration somewhere in the components that produce an audible noise. The first thing you should do is a basic visual inspection to verify that the pads are serviceble with even wear. If you are experiencing a "groan" sound with brake application, my first suspicion would be a completely worn down friction material with the pad backing plate bearing against the rotor.

Squeak and squeal noises can be difficult to run down, but sometimes hard brake usage, such as running down a canyon or mountain hard with lots of braking into the corners can cure noise problems, at least temporarily.

Noise is also a function of pad material, and low noise pads such as kevlar or ceramic are often quieter, but not as effective as semi-metallic compounds.

Failing wheel bearings usually make a continuous growling sound that is independent of power or brake application, so if this noise only occurs when the brakes are applied, it's very unlikely that it is wheel bearing related.

The OEM pads on my '88 190E 2.6 worked very well, but they dusted and squealed terribly and were tough on the rotors. I elected to install a set of Repco Deluxe (not Metalmasters) pads at 15K miles based on some advice from other owners, but knew they would be less effective. The car now has 72K miles, and there is plenty of life left in the pads. In recent years the pads seemed to become less effective - probably due to a lot of in-town driving, so I decided to do an "Italian tuneup". On a recent trip to Northern CA I drove the car hard over back roads (State Routes 33, 198 and 25), which required constant braking approaching corners. As a result of the hard use the glaze on the pads was broken and the pads became much more effective, so I am now, again, happy with the brake performance

Duke

OK, when I removed the front brake calipers I found that the pads were quite worn yet not to the point here it was a grave situation. I checked the rotors and found they were in very good shape, put in the new OEM pads and re-assembled everything. The groaning sound was gone however, a very small groan could be heard if the ANTILOCK light came on. Before I replaced the pads the groan was quite loud if the ANTILOCK light was on. Now it was barely audible and in addition, it hardly ever comes on anymore. A Mercedes mechanic I spoke to recently told me to replace the horn ring and brushes to remedy that problem. I found that very interesting.
Thom

__________________
1987 300E
1967 Jaguar E-type Series I, 2+2