By Christina Thomas

Time and again, the advantages of wet brakes have been proven, and fortunately most modern tractors are equipped with them.  However, complaints about brake chatter found on agricultural and off-highway equipment continue to tarnish the benefits of such stopping devices. Naturally, many farmers are concerned by the braking noise and vibration. Therefore, to help you stop the annoying din and bumpy ride, sought answers from The Lubrizol Corporation’s tractor hydraulic fluid experts.

Q: First, what are the differences between wet and dry brakes?
A: Wet brakes are encased in the tractor’s axle housing for two reasons:

  1. It enables the brakes to be bathed in oil, which cools them under heavy loads.
  2. It protects the brakes from harsh conditions such as dust, mud, water and moisture.

Dry brakes, on the other hand, are not encased in the tractor’s axle housing, and therefore, the brakes operate dry (without oil) and are exposed to harsh conditions (dust, mud, water and moisture).

While there are a few OEMs that produce tractors with a dry brake system, the majority of farm machinery is equipped with wet brakes.

Q: What is brake chatter on a farm tractor? 
A: Farmers experience brake chatter when they hear loud squeaky noises from the braking system (when braking). Producers may also feel vibration of the tractor. 
Q: Why does brake chatter only occur in wet brake systems? 
A: The chatter is a function of the oil/metal surface interaction, and the oil having an impact on the frictional characteristics of the braking surface. Since dry brakes are not immersed in oil, the brake chatter phenomenon does not occur.
Q: What causes brake chatter in wet brake systems?
A: The brake chatter phenomenon can be caused by several factors, including:

  • High amount of fluid degradation
  • Large contamination of water in the fluids
  • Lack of sufficient lubrication of the brake couplings
  • Degradation of the brake friction material from high loads with extensive applications of heavy braking
Q: What are the dangers of brake chatter?
A: Heavy brake chatter can be very unpleasant (annoying) for the farmer and possibly damage the tractor if allowed to continue over a long period of time.
Q: What can be done to not only correct brake chatter but also prevent it? 
A: Since the type of fluid used in a wet brake system has a large effect on the amount of brake chatter experienced, a farmer hearing brake noise and feeling vibration should change the tractor hydraulic fluid immediately.
Q: What type of tractor hydraulic fluid should be used to prevent brake chatter? 
A: A farmer should be sure to select a high performing tractor hydraulic fluid that provides excellent wet brake performance. 
Q: With more low-quality tractor hydraulic fluids popping up on retail shelves every day, how can a farmer choose the proper fluid?
A: Let’s view a checklist of product features to look for. As a rule of thumb, most oil companies and original equipment manufacturers selling high performing fluids will spell out these attributes right on the label.

  • The product should be chemically engineered specifically for farm tractors and other off-highway equipment and should list OEM specifications.
  • The fluid should be multi-purpose, enabling lubrication of a tractor’s transmission, final drives, clutches, wet brakes and hydraulic systems.
  • The lubricant should prevent brake chatter or provide excellent wet brake performance.
  • The product should offer excellent oxidation resistance.
  • The fluid should have excellent wear protection or “anti-wear” for clutches, gears and hydraulic pumps.
  • The lubricant should have high water tolerance, which is the ability to protect parts from erosion and corrosion when contaminated with water.
  • The product should be suitable for year-round use, including cold temperatures.

In order to help you select fluids you can trust we launched the Authenticated mark. Fluids endorsed by this mark meet and often exceed OEM credentials, providing you optimal protection against wear, rust, oxidation, brake chatter, extreme temperatures and, ultimately, premature equipment failure. Find out more now!


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