Noisy Service Brakes

[winnetou]

I have a 2010 Winnebago Tour 40CD built on a Freightliner chassis with drum brakes all around.

I purchased the unit as new, from a Seattle area dealer, in October 2010, when it had 3,500 miles on it.

The coach now has 11,000 miles on it. For some time now I have been concerned with the noisy service brake operation, which I can best describe as follows.

When starting out cold, during the first few applications the brakes emit a low pitched, loud squealing sound (almost like those pesky dump trucks). This clears up after driving a mile or so, and / or after the brakes have been applied a few times (that being of little comfort to my neighbors, when I first roll out of our downhill driveway).

While the brakes are still relatively cool, they emit a soft, high-pitched sound, which occurs closer to stopping speed. This condition worsens as the brakes are subjected to fairly heavy usage at low speeds, such as was the case during a recent stop-and-go drive in heavy traffic, along the Pacific Coast Highway in the Los Angeles area.

In summary, very seldom do the brakes bring the coach to a stop in complete silence.

It is important to point out that I used to make my living driving passenger highway coaches, as well as tractor-trailers, and that I am accustomed to using the engine brake at all times, and whenever possible, plan my stops so as to only apply the service brakes at low speeds, mostly when the engine brake deactivates due to low speed.

Earlier on, I called Freightliner about this condition and was advised that because the coach is “new” the brakes need to be burnished. They would not authorize my local dealer to pull the wheels and inspect the brakes. In my opinion, at 3,500 miles, when I bought the coach, the brakes were no longer “new”, at least not for the purpose of burnishing them.

I would appreciate your thoughts, comments and suggestions on if and how the situation can possibly be remedied.

[dickandlois]

Winnetou,

From reading your post,sounds like you live in the Northwest area of the country. That being the case, the area has higher humidity then some areas of the country.

Things get rusty real fast when setting and my thoughts are.The drums are building up a layer of rust that takes a little time to wear off.

The Brake shoes will absorb moisture and they need to get heated up to dry out. Do not know if you have had the opportunity to look at the brakes when the wheels and brake drums are off, but they are big brake shoes.

Have you had the Chassis systems greased with a good quality grease? Many shops do not use a higher end grease and they are not created equally.

The S-Cams and brake shoe hardware may need some TLC. Like cleaning and lubrication.This does require the removal of the brake drums. A quality job is labor intensive if done properly.

When the S- Cams do not move freely the problem you described will be noticed.

The hardest thing on the brake systems and hardware is just setting for extended periods of time, so a good run with the coach an a location where you can apply the brakes to slow down from road speed using just the brakes keeps things dry and freed up. All the other drive train parts benefit for these runs also.

I live in a damp part of the country, so the coach gets a work out about every 3 months at expressway and stop go driving when a nice day comes around and the traffic is light.

I do need to get my front S-cams pulled,cleaned and lubed as the brakes are doing some of the same things you described.

When I apply the brakes hard I get a good thump,Yep ! I do need to clean the S-Cams and all the parts myself.

R.M.